Download Potentially Harmful Activity (X)

Structural habitat provided by rockweed and kelp within the PBGB LOMA
Potentially Harmful Activity (X)
Potentially Harmful Stressor (X)
Fishing
Other
harvest
Seabed
alteration
Coastal
alteration
Disturbance
Bottom trawl
Scallop dredges
Clam dredges
Midwater trawl
Gillnets (bottom)
Gillnets (pelagic)
Longline
Seine (pelagic)
Recreational cod fishery
Crab pots
Lobster pots
Whelk pots
Other (specify)
Otter trapping
Seal hunt
Seabird hunt
Seaweed harvest
Anchor drops/drags
Ore spill
Fish offal dumping
Finfish aquaculture
Dredge spoil dumping
Dredging
Mining/Oil & gas drilling
Cables
Freshwater diversion
Subtidal construction
Intertidal/coastal
construction
Marine
pollution
Climate
Change
X
X
X
X
X
X
Harmful
species
X
X
Other (specify)
Vessel traffic
Ship strikes
Ecotourism
Marine construction
Seismic surveys
Navy sonar
Other (specify)
Oil pollution
Industrial effluent
Fishplant effluent
Sewage
Historic military waste
Long range transport of nutrients
Acid rain
Persistent Organic Pollutants
(Eutrophication
)
Ghost nets
Litter
Other contaminants (specify)
Ice distribution
Temperature change
Sea-level rise
Ocean acidification
Current shifts
Increased storm events
Increased UV light
Oxygen depletion
Changes in freshwater runoff
Other (specify)
Green crab
Membranipora
Golden Star Tunicate
Violet Tunicate
Vase Tunicate
Codium fragile
Clubbed Tunicate
Didemnum
Harmful Algal Blooms
Disease organisms (human waste)
Disease organisms (aquaculture)
Other (specify)
X
X
X
X
X
X
X
X
X
X
Other
1
Background Information
Rockweed is a very general term for several species of Fucus and Ascophyllum, while Kelp
refers to Laminaria species. Kelp and rockweed are the dominant large structural seaweeds
in the LOMA, with rockweeds dominating the intertidal zone and kelps dominating the
subtidal zone in areas with appropriate hard, stable substrate (Chapman, A. R. O., 1987). In
the northern areas of the LOMA, ice scour removes much of the intertidal seaweed annually,
but in southern areas and deeper water, large forests of these perennial macrophytes provide
food, shelter and attachment sites for a wide range of marine organisms (Chapman, A. R. O.,
1987; Fisheries and Oceans Canada, 2008a; Fisheries and Oceans Canada, 2008b; Fisheries
and Oceans Canada, 2008c; Fisheries and Oceans Canada, 2008d).
Rockweed beds leave a cool, wet, protective blanket of vegetation when the tide goes out,
which prevents the intertidal animals from drying out. Many species of fish, seabirds and
invertebrates also depend on these rockweed "forests" for food and for refuge from hungry
predators. Few animals eat the healthy, adult rockweed plants. However, many
invertebrates, such as urchins, periwinkles and amphipods, feed on the young plants,
fragments that continually break off, as well as on the mucous, bacteria and epiphytes
(smaller attached plants) found on the rockweed fronds. These vegetarians (herbivores) are
themselves much sought after by fish, seabirds and other carnivores that forage among the
fronds. At least 30 species of fish, 15 species of birds and scores of different invertebrates
use the rockweed beds at some point in their life cycle. The beds seem to be a critical
nursery area for many species of fish, including several commercially important ones such as
pollock, herring and flounder. For instance, in early May, young pollock, only a few
centimetres in length, move shoreward to forage in the seaweed "forest" as the tide rises, and
retreat seaward as it falls. They eat the abundant small animals hiding amongst the
rockweeds and grow rapidly. Seabirds also forage in the rockweed (Percy, J. A., 1996).
Similarly, kelp forests provide important food resources for invertebrate grazers, primarily
sea urchins, and are also producers of suspended food for many filter-feeding organisms.
Marine vegetation such as kelp and rockweed increase the complexity of a habitat, providing
high quality refuge and feeding habitats, which are important features of high quality nursery
habitats (Borg, A., Phil, L., & Wennhage, H., 1997). They provide habitat for a wide range
of juvenile fish, shellfish and other invertebrate species, and foraging areas for adult fish
(Fisheries and Oceans Canada, 2008a; Fisheries and Oceans Canada, 2008b; Fisheries and
Oceans Canada, 2008d)
Even after they are torn loose from their rocky beds by the storms of autumn and winter,
these seaweeds continue to be valuable in the marine environment. The still living,
photosynthesizing fronds accumulate in large floating rafts that drift with the currents. This
jumble of vegetation teems with small marine animals seeking food and refuge, including
larval lobsters and fish. These in turn attract seabirds such as phalaropes and terns, as well as
larger fish. After drifting for weeks or months, the rafts wash ashore and pile up in long
windrows at the high tide mark. Sandflies, beach fleas, bacteria and fungi thrive in the dying
vegetable matter. They slowly decompose this natural compost heap into a brownish sludge,
rich in fertilizing nutrients. The decaying mass may be refloated by subsequent high tides,
drifting elsewhere to strand and rot, again and again until it finally disappears. The small
particles formed during decomposition are an important food for bottom dwelling animals.
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The soluble material is a potent fertilizer that stimulates the production of phytoplankton and
other marine plants. Recent studies also suggest that some of the colloidal organic
compounds produced may be eaten by adult and larval scallops (Percy, J. A., 1996).
As marine plants form a part of the fish habitat, Section 31 of the Fisheries Act (1977)
provides protection against any harmful alteration/description or destruction of the habitat.
Scoping
Seaweed harvest:
Seaweeds such as rockweed and kelp provide a source of food for many common benthic
organisms such as sea urchins and snails, and provide structural habitat for a wide range of
benthic organisms. Seaweed harvest may cause major disturbance and destruction of benthic
communities. Seaweed was traditionally harvested in rural communities throughout coastal
Newfoundland for use as a fertilizer on local gardens, and although this practice continues
today, gardens are less common, and seaweed fertilizers have often been replaced or
supplemented with commercial products. Some limited, small scale commercial harvests of
seaweeds, such as kelp and Irish moss, have been conducted within coastal areas, but since
the activity is not widespread within the LOMA, and both rockweed and kelp are common
throughout coastal areas of the LOMA, seaweed harvest is not considered to be a significant
stressor. Screened out.
Anchor drops/drags:
Anchor damage may cause significant disturbance and destruction of sensitive benthic
habitats. Rockweed and kelp are relatively hardy and widespread within coastal areas of the
LOMA, forming extensive beds of individuals attached firmly to hard substrates that are
fairly resistant to damage. Recovery from extensive seasonal damage from ice scour and
grazing by sea urchins occurs annually throughout the LOMA and therefore the relatively
minor damage expected to result from anchor drags are unlikely to cause serious damage to
the population as a whole. Screened out.
Fish offal dumping:
The dumping of large quantities of fish offal in the subtidal zone can smother hard rocky
substrate where kelp thrive, and can lead to increase nutrients concentrations causing kelp to
be overgrown with epiphytic algae (Dr. Robert Hooper, Director, Bonne Bay Marine Station,
Memorial University of Newfoundland, Norris Point, NL, A0K 3VO, “pers. comm.").There
are approximately 85 active fish plants operating in the LOMA, and 31 approved ocean
dumping sites for fish offal, although ocean dumping is now highly regulated and much of
this offal is now diverted to alternate uses such as feed, fertilizer and other valued products.
Since this threat is declining, and restricted to a relatively small number of sites, and both
rockweed and kelp are common throughout coastal areas of the LOMA, offal dumping is not
considered be a significant stressor. Screened out.
Finfish aquaculture:
Caged finfish aquaculture operations in marine waters of the LOMA raise high densities of
fish in cages that allow the free exchange with the surrounding marine environment. Finfish
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aquaculture is a major contributor of nutrient loading to coastal waters of the LOMA, which
may stimulate growth of macroalgae if concentrations are low, but these potential impacts are
covered under eutrophication. Environment Canada guidelines recommend that cages should
be located where water circulation will allow adequate dispersion and maintain high levels of
dissolved oxygen, and “shallow areas and areas with aquatic vegetation should be avoided”
(Environment Canada, 2001). Section 35.2 of the Fisheries Act protects fish habitat from
harmful alteration, disruption and destruction and therefore Fisheries Act reviews conducted
in relation the Environmental Assessment of new projects would also strive to mitigate any
harmful impacts by ensuring that cages are not sited directly over macrophyte beds or other
sensitive habitat. Indirect effects of nutrient loading from aquaculture may be beneficial to
macrophyte beds unless nutrient loading is excessive, but such impacts would be considered
under eutrophication. Currently, salmonoid aquaculture is largely confined to the Bay
d’Espoir area, and although the industry is expected to grow substantially over the next ten
years, along with farming of cod and possibly other finfish species, impacts on macroalgae is
not expected to be significant. Screened out.
Dredge spoil dumping:
Dredge spoil dumping can result in the direct destruction of benthic communities including
kelp beds through smothering, and harmful alteration and disturbance resulting from
suspended sediments and inputs of contaminants. Environment Canada now closely
regulates ocean dumping, and dredge material must be monitored for contaminants and meet
rigorous standards before ocean dumping is permitted. The practice is now uncommon in the
LOMA and is therefore not expected to have a significant impact on macrophyte
communities within the LOMA. Screened out.
Dredging:
Sediments accumulate in harbours as a result of river flow, shoreline erosion, storm-water
runoff, and direct discharge of suspended solids (sewage, fish plant waste, etc). Eighty
harbours within the LOMA are dredged on a regular basis to facilitate continued navigation
or allow access to larger ships but only a portion of this number will require dredging in a
given year. Dredging is also conducted in association with specific development projects
such as expansion of marinas or other coastal works. Dredging can destroy macrophyte beds
directly through physical removal of plants and or their substrates, and increase the amount
of suspended sediment, leading to decreased water clarity and light penetration. Dredging
can also alter currents and sedimentation patterns leading to erosion and increased
sedimentation of adjacent macrophyte beds, or cover rocky substrates preventing attachment
of rockweed and kelp. Dredging is a relatively common activity in coastal areas occupied by
kelp and rockweed therefore it may be a significant stressor to the CP. Screened in.
Subtidal construction:
The construction of causeways, wharves and other marine structures may lead to the harmful
alteration, disruption or destruction (HADD) of macrophyte beds, with potentially permanent
loss of habitat in the footprint of the structure and temporary disruption or destruction in the
surrounding area during the construction phase as a result of dredging, infilling,
sedimentation, etc. The total footprint of these projects is small relative to the area occupied
by rockweed and kelp, which is widespread on rocky intertidal and subtidal habitats
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throughout the LOMA. Dredging is likely the most harmful activity which may occur in
association with these construction projects, and is considered separately. Other impacts from
causeway and wharf construction are not considered a major stressor to rockweed and kelp
within the LOMA as these structures may actually provide new habitat for these species to
colonize. Screened out.
Intertidal construction:
The construction of seawalls, and other coastal structures may lead to the harmful alteration,
disruption or destruction (HADD) of intertidal rockweed beds, with potentially permanent
loss of habitat in the footprint of the structure if it extends into the intertidal zone, and
temporary disruption or destruction of rockweed and kelp in the surrounding area during the
construction phase as a result of dredging, infilling, sedimentation, etc. The total footprint of
these projects is small relative to the area occupied by rockweed, which is widespread on
rocky intertidal habitats throughout the LOMA. Dredging is likely the most harmful activity
which may occur in association with these construction projects, and is considered
separately. Other impacts from seawalls and construction of other coastal structures are not
considered a major threat to rockweed and kelp within the LOMA as these structures may
actually provide new habitat for these species to colonize. Screened out.
Oil pollution:
Many intertidal and subtidal areas of the LOMA where rockweed and kelp occur, including
Placentia Bay, Conception Bay and the south coast, are exposed to a significant level of
tanker traffic on route to local ports and ports in the Gulf of St. Lawrence. This exposure
increases the risk of oil pollution from in-port (transfer) spills, tanker accidents at sea, and
oily ballast discharge. Other sources of oil pollution which may affect coastal habitats
include fuel oil spills from marine vessels of all sizes, and land runoff (refueling spills,
storage tank leaks, fuel combustion emissions, etc.). Chronic oil pollution is a significant
problem in coastal areas of the LOMA, particularly in active harbours and ports (Fisheries
and Oceans Canada, 2002) and the risk of a large oil spill is a serious concern in areas with
high tanker traffic. Oil pollution can cause direct harm to macrophyte beds by physically
coating the plants, blocking sunlight and preventing photosynthesis. Calm, sheltered
shorelines, marshes and river estuaries are among the most sensitive areas to oil, providing
quiet zones where oils can accumulate and bind to suspended particles forming dense tar
mats (The International Tanker Owners Pollution Federation Limited, 2002). Low oxygen
levels typical of these habitats limit the biodegradation of oil and result in extremely slow
degradation with toxic components persisting for as much as ten years or more, depending on
the amount and type of oil spilled. Because rockweed and kelp thrive in high energy habitats
with bedrock and boulder substrates, they are not considered to be highly vulnerable to the
short or long term impacts of oil pollution. A large oil spill in a coastal area of the LOMA,
and the associated clean-up operation would almost certainly result in harm to localized beds
of rockweed and kelp, but since the CP is widespread, large spills warranting clean up would
be infrequent and affect only a small portion of the coastal area of the LOMA, oil pollution is
not considered to be a key stressor. Screened out.
5
Fishplant effluent:
Some kelp species thrive near fish plant outfalls due to extra nitrogen unless the temperature
or nitrogen levels are very high (Dr. Robert Hooper, Director, Bonne Bay Marine Station,
Memorial University of Newfoundland, Norris Point, NL, A0K 3VO, “pers. comm.”). There
are approximately 85 active fish plants discharging effluent into coastal waters of the LOMA,
largely untreated. Effluent discharge can change water temperature, salinity, or chemical
characteristics, thereby disrupting biochemical processes such as growth and reproduction.
These processes are cued to a narrow range of water quality characteristics (Fisheries and
Oceans Canada, 2008a; Fisheries and Oceans Canada, 2008c). Since fishplant effluent is
discharged in large quantities throughout many coastal areas of the LOMA where kelp and
rockweed grow, it may be a significant stressor. Screened in.
Sewage:
Some kelp species thrive near sewage outfalls and fish plants due to extra nitrogen, unless the
temperature or nitrogen levels are very high (Dr. Robert Hooper, Director, Bonne Bay
Marine Station, Memorial University of Newfoundland, Norris Point, NL, A0K 3VO, pers.
comm.). Human sewage discharge into the LOMA is significant and largely untreated, with
sewage from close to 100 communities with a combined population of around 295,000
people currently discharging into the coastal zone. Effluent discharge can change water
temperature, salinity, or chemical characteristics, thereby disrupting biochemical processes
such as growth and reproduction. These processes are cued to a narrow range of water quality
characteristics (Fisheries and Oceans Canada, 2008a; Fisheries and Oceans Canada, 2008c).
Since sewage effluent is discharged in large quantities throughout many coastal areas of the
LOMA where kelp and rockweed grow, it may be a significant stressor and has been
screened in for further assessment. Screened in.
Eutrophication:
An over-supply of nutrients in aquatic ecosystems, known as eutrophication, may stimulate
excessive and undesirable algal growth (blooms), particularly in sheltered, low flushing
coastal waters. In severe cases, the surface scum will be dense and persistent enough to
block light from reaching macrophyte beds beneath the sea surface, leading to mortality.
Eutrophication also leads to decreased oxygen levels in the water column, seriously
compromising the nursery habitat provided by kelp and rockweed. Within the LOMA, major
contributors of organic wastes into the coastal waters are fish plant waste, sewage, finfish
aquaculture and sawmill wastes. Although eutrophication develops in localized coastal areas
throughout the LOMA, it is not widespread. DFO water quality surveys conducted in
Placentia Bay in nine relatively sheltered areas (Lawn, St. Lawrence, Burin, Marystown,
Baine Harbour, Arnold’s Cove, Ship Harbour, Fox Harbour and Northeast Arm Placentia)
found no significant reduction of water quality (pH, turbidity, dissolved oxygen, salinity or
redox) near sewage outfalls compared to reference sites (Fisheries and Oceans Canada,
2005). Since kelp and rockweed thrive in high energy habitats where nutrients are rapidly
diluted and eutrophication is less likely to occur, and there is no evidence that large coastal
areas of the LOMA are affected by eutrophication, it is not considered a key stressor.
Screened out.
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Ice distribution:
Ice scour is a major natural phenomenon which annually removes kelp and rockweed beds,
particularly in the northern areas of the LOMA. Climate change is likely to reduce this
stressor, and consequently limit the impact to kelp and rockweed within the LOMA over
time. No significant impact is expected over the next ten years. Screened out.
Temperature change:
Climate change models predict a general increase in water temperatures, particularly in
shallow coastal areas of the LOMA. Kelp and rockweed thrive in slightly warmer regions
such as the Maritime provinces and New England. Warmer water temperature may be
detrimental for this CP, as warm temperature is critical for the growth of Membranipora with
maximum growth occurring when water temperatures reach 15oC, usually in August in most
areas, and growth continuing until December (Dr. Robert Hooper, Director, Bonne Bay
Marine Station, Memorial University of Newfoundland, Norris Point, NL, A0K 3VO, pers.
comm.;(Dr.Robert Hooper, 2009; Saunders & Metaxas, 2009). This invasive colonial
bryozoan of European origin grows on kelp and other marine plants, secreting a protective
limestone covering which forms a tough, white lace-like crust over the flexible, rubbery
surface of the kelp blade. Kelp blades that are heavily encrusted with Membranipora
become brittle and more susceptible to breakage during storm surge. Due to the warmer
temperatures, kelp on the west and south coasts have suffered major impacts as a result of
this Membranipora, with kelp basically going from a perennial to annual, while on the cooler
northeast coast, Membranipora is present but the level of harm to kelp is much lower.
Climate change could potentially intensify the growth of this harmful species. In 2006, as a
result of a warm winter and early spring, recruitment pulses began in June, while in 2007,
following a colder winter and spring, only one recruitment pulse was evident in August.
Because even a minor increase in temperature, and greater inter-annual variation leading to
frequent warm summers, may intensify the devastating impacts of Membranipora on kelp
and to a lesser extent rockweed, temperature change has been screened in for further
assessment in relation to this CP (Dr. Robert Hooper, Director, Bonne Bay Marine Station,
Memorial University of Newfoundland, Norris Point, NL, A0K 3VO, “pers. comm.”;
Saunders, M. I. & Metaxas, A., 2009). Screened in.
Increased storm events:
Recent scientific evidence suggests a link between the destructive power (or intensity) of
hurricanes and higher ocean temperatures, driven in large part by global warming (Webster et
al., 2005). Two factors that contribute to more intense tropical cyclones, ocean heat content
and water vapour, have both increased over the past several decades. The world’s oceans
have absorbed about 20 times more heat than the atmosphere over the past half-century,
leading to higher temperatures not only in surface waters (e.g., depths of less than 100 feet)
but also down to substantial depths, with the most severe warming occurring in the first
1,500 feet below the surface (Coral Reef Targeted Research Program, 2007; Planet Ark,
2007). As this warming occurs, the oceans expand and raise sea level. This expansion,
combined with the inflow of water from melting land ice, has raised global sea level more
than one inch over the last decade (Coral Reef Targeted Research Program, 2007). In
addition, observations of atmospheric humidity over the oceans show that water vapour
content has increased four percent since 1970. Because warm air holds more water vapour
7
than cold air, these findings correlate with an increase in air temperature (Coral Reef
Targeted Research Program, 2007). Kelp and rockweed thrive in high energy environments,
but increased storm events could increase the harmful effects of Membranipora which has
since spread to all coastal areas of the LOMA. This invasive colonial bryozoan of European
origin grows on kelp and other marine plants, secreting a protective limestone covering
which forms a tough, white lace-like crust over the flexible, rubbery surface of the kelp
blade. Kelp blades that are heavily encrusted with Membranipora become brittle and more
susceptible to breakage during storm surge (Dr. Robert Hooper, Director, Bonne Bay Marine
Station, Memorial University of Newfoundland, Norris Point, NL, A0K 3VO, pers. comm.” ;
Saunders & Metaxas, 2009). Even a minor increase in storm events may intensify the
devastating impacts of Membranipora on kelp and to a lesser extent rockweed, but these
impacts will be considered under Membranipora. Screened out.
Green crab (Carcinus maenas):
The European green crab is an aggressive and hardy species that preys on benthic organisms
including clams, mussels, scallops, and juvenile fish. They prefer sheltered sandy habitats,
burrowing into the sand, but are also found hidden in seaweed such as rockweed and kelp,
particularly in beds occupying lower energy environments. Green crab was first detected in
North Harbour, Placentia Bay in 2007, and has since been found in several sites in Placentia
Bay as well as two sites on the west coast. The population has reached high densities in
North Harbour and has had a devastating effect on species biodiversity: clam, scallop and
mussels beds in North Harbour have been completely destroyed, the native rock crab is
virtually absent, and other benthic organisms are no longer evident (McKenzie, C. H. Baines
T. and Park L. E., 2008). Although green crab do not harm rockweed and kelp or the
structural habitat they provide, the lack of biodiversity resulting from green crab infestation
may mean that the CP provides habitat for green crab rather than the usual diversity of
species, particularly in beds occupying lower energy environments. This may actually
increase the value of adjacent kelp and rockweed beds in high energy environments which
tend to be avoided by green crab and may provide a haven for displaced native species.
Thus, green crab is not considered a key stressor to kelp and rockweed, and has been
screened out, but the effects of green crab in sheltered habitats and Membranipora (see
below) in exposed habitats may result in a drastic combined impact on structural habitat and
biodiversity in coastal areas of the LOMA. Screened out.
Membranipora membranacea (Lacey bryozoan):
Membranipora was first detected by MUN Scientist Bob Hooper in Bonne Bay in 2002, and
has since spread to all coastal areas of the LOMA. This invasive colonial bryozoan of
European origin grows on kelp and other marine plants, secreting a protective limestone
covering which forms a tough, white lace-like crust over the flexible, rubbery surface of the
kelp blade. Kelp blades that are heavily encrusted with Membranipora become brittle and
more susceptible to breakage during storm surge. In high energy areas, encrusted blades are
far more prone to break off. In some areas, this has lead to the removal of entire kelp beds.
Membranipora is expected to have a significant impact on the structural habitat provided by
kelp and to a lesser degree rockweed, with implications for biodiversity and recruitment of
juvenile fish and shellfish, such as lobster, which utilize kelp beds as nursery habitat
(Fisheries and Oceans Canada, 2008b). Sea urchins thrive on Membranipora infested kelp,
8
but it puts a bad taste on the gonads, which negatively affects their commercial value (Dr.
Robert Hooper, Director, Bonne Bay Marine Station, Memorial University of Newfoundland,
Norris Point, NL, A0K 3VO, “pers. comm.”). Screened in.
Codium fragile (Oyster thief):
This invasive macroalgae grows rapidly on any hard surface including rocks, boulders,
cobble, wharves, boat hulls and wild or cultured shellfish in the intertidal and subtidal marine
or brackish waters. It is known to impair the growth of shellfish, and is known as the “oyster
thief” – when it attaches to shellfish it is buoyant enough to move them from their beds, and
so is known to steal cultured oysters. It has been found to foul fishing nets and outgrow and
exclude native kelps from bare substrates, often invading areas where Membranipora
infestation has removed the kelp beds. In heavily infested areas, large amounts of this
seaweed have been known to wash up and rot on beaches, making them unusable for
recreation. This can be spread by ocean currents, boats, fishing gear and shellfish transfer
(Green, D., McKenzie, C., & Mouland, D., 2008). To date, the oyster thief has not been
detected within the LOMA, but since Membranipora has heavily infested kelp beds within
the LOMA, there is serious concern that the oyster thief will follow in its wake, since the
occurrence of Membranipora in Nova Scotia has corresponded to the invasion of the subtidal
by Codium fragile. In areas where kelp beds have been reduced or removed by
Membranipora, Codium has established itself, preventing kelp from returning. Thus, by
working together, Membranipora and Codium have brought about what may be long-lasting
change in the subtidal ecosystem that could have negative effects on biodiversity and
commercial resource use, and there is concern that this may be repeated in Newfoundland.
Codium is therefore identified as a key stressor to kelp, and to a lesser degree rockweed.
Screened in.
Key Activities/Stressors:
 Dredging
 Fishplant effluent
 Sewage
 Temperature Change
 Membranipora
 Codium fragile
9
Reference List
1. Borg, A., Phil, L., & Wennhage, H. (1997). Habitat Choice by Juvenile Cod
(Gadus morhua L.) on Sandy Soft Bottoms with Different Vegetation Types.
Helgoland Marine Research, 51, 197-212.
2. Chapman, A. R. O. (1987). A case study for the wild harvest and culture of
Laminaria longicruris in Eastern Canada (Rep. No. FAO Fisheries Technical
Report 281). Rome: Food and Agriculture Organization of the United Nations.
3. Coral Reef Targeted Research Program (2007). Global Warming is Destroying
Coral Reefs. Science Daily [Announcement posted on the World Wide Web].
From the World Wide Web:
http://www.sciencedaily.com/releases/2007/12/07121352600.htm
4. Environment Canada. Environmental Assessment of Marine Finfish
Aquaculture Projects: Guidelines for Consideration of Environment Canada
Expertise. 1-22. 2001. 45 Alderney Drive, Dartmouth, NS, Environment
Canada, Atlantic Region.
Ref Type: Pamphlet
5. Fisheries and Oceans Canada. Harbour Sediment Database (Unpublished). Park,
L. 2002. Ref Type: Unpublished Work
6. Fisheries and Oceans Canada. Water Quality Surveys in Placentia Bay,
Newfoundland and Labrador (Unpublished). Park, L. 2005. Ref Type:
Unpublished Work
7. Fisheries and Oceans Canada. Cabbage Kelp, Species Profile Series, No. 15.
2008a. Ref Type: Pamphlet
8. Fisheries and Oceans Canada. Finger Kelp, Coastal Zone Species Profile Series,
No 14. 2008b. Ref Type: Pamphlet
9. Fisheries and Oceans Canada. Knotted Wrack, Coastal Zone Species Profile
Series, No.16. 2008c. Ref Type: Pamphlet
10. Fisheries and Oceans Canada. Winged Kelp, Species Profile Series, No 13.
2008d. Ref Type: Pamphlet
11. Green, D., McKenzie, C., & Mouland, D. A Guide to Aquatic Invasive Species.
2008. St. John's, Newfoundland.
Ref Type: Pamphlet
12. McKenzie, C. H. B. T. a. P. L. E. Aquatic Invasive Species,
Newfoundland and Labrador Region 2007/08 Survey Report. 2008. NAFC,
Fisheries and Oceans Canada. Ref Type: Video Recording
10
13. Percy, J. A. The Seaweed Forest: Rockweed Harvesting in the Bay of Fundy.
Fundy Issues #4. 1996. Annapolis Royal, NS, The Clean Annapolis River
Project and Bay of Fundy Ecosystem Project. Ref Type: Pamphlet
14. Planet Ark (2007). Seas could Rise Twice as High as Predicted. Planet Ark,
World Environment News [Announcement posted on the World Wide Web]. 1224-2007, from the World Wide Web:
www.planetark.com/avantgo/dailynewsstory.cfm?new_46052
15. Saunders, M. I. & Metaxas, A. (2009). Effects of Temperature, Size, and Food
on the Growth of Membranipora membranacea in Laboratory and Field Studies.
Mar.Biol., D)I 10.1007/s00227-009-1254-6.
16. The International Tanker Owners Pollution Federation Limited (2002). Fate of
Marine Oil Spills. Technical Information Paper [Announcement posted on the
World Wide Web]. From the World Wide Web:
www.dfg.ca.gov/ospr/response/rtk/misc/oilspill_guidance/itopf_fate_of_marine_oil_spills.pdf
17. Webster, P. J., Holland, G. J., Curry, J. A., & Chang, H. A. (2005). Changes in
Tropical Cyclone Number, Duration, and Intensity in a Warming Environment.
Science, 309, 1844-1846.
11
Structural habitat provided by rockweed and kelp within the PBGB LOMA
Dredging
Magnitude of Interaction
Areal extent:
 Kelp and rockweed are the dominant seaweeds in the subtidal and intertidal habitats
where appropriate hard substrates are available. They form perennial beds, and spread
through the release of motile spores that swim until they find suitable habitat within
which to settle. Ice scour and sea urchin grazing cause a natural cycle in the locations of
seaweed beds, and therefore it is difficult to map the changing distribution of these
species, but all appropriate hard intertidal (rockweed) and subtidal (kelp) substrates can
be considered kelp and rockweed habitat. They readily colonize available habitats, and
may rapidly colonize freshly dredged harbours if hard substrate is made available.
 Dredging is a common activity, as regular harbour maintenance and also associated with
coastal construction projects. Eighty harbours within the LOMA are dredged on a regular
basis (Figure 1) but only a portion of this number will require dredging in a given year.
Figure 1. Regular harbour dredging sites (red dots along coast) within the LOMA (Fisheries
and Oceans Canada, 2005).


Other projects may occur at any site along the coast, but are most frequently associated
with an existing community.
Dredging is considered a chronic stressor that is likely to occur every year, but is not
restricted to a specific area, and therefore we have estimated the areal extent as low to
medium.
Score 4
1
Contact:
 If dredging occurs in an area occupied by kelp or rockweed, contact will be unavoidable
Score 10
Duration:
 Kelp and rockweed are perennial and occupy an area throughout the year, and at the same
time they actively colonize new sites every year.
 Dredging occurs regularly every year within the LOMA, and may occur at any time, but
is not continuous. Intermittent activities are given a moderate score (30-70%) depending
on the frequency and duration of each event. Dredging is a fairly common activity,
especially in warmer months (May-October).
Score 6
Intensity:
 We do not have global data on dredging, but given our small harbours, and limited
industrial activities, we are unlikely to be high on a global scale. Given our highly coastal
population and high dependency on the ocean, high number of boats per capita etc, we
are estimated to have a moderate frequency.
Score 6
Magnitude of Interaction: (4x10x6x6)/1000 = 1.4
Sensitivity
Sensitivity of the CP to acute impacts:
 Dredging can destroy kelp and rockweed beds directly through physical removal of
plants, and can also alter currents and sedimentation patterns leading to increased
sedimentation which may harmfully impact adjacent kelp or rockweed beds.
 Kelp and rockweed are highly sensitive to light attenuation and changes in turbidity
resulting from increased suspended sediments. Furthermore, large amounts of sediment
may cover rocky substrates and prevent attachment of seaweeds.
 Acute sensitivity is considered to be high.
Score 8
Sensitivity of the CP to chronic impacts:
 Kelp and rockweed are perennial, and relatively resilient. If the upper portion of the
plant is damaged or removed, the plants can grow back from the lower portion of the
plant as long as enough remains.
 Further, the plants spread through the release of motile spores that swim until they find
suitable habitat within which to settle, and they readily colonize any available habitat.
Kelp and rockweed have adapted to cope with natural destruction by ice scour and sea
urchin grazing, and can recover fairly rapidly from damage resulting from dredging.
2


Dredging can also provide new hard substrates for attachment, and so can provide new
habitat for kelp and rockweed.
Chronic sensitivity is considered to be low.
Score 3
Sensitivity of ecosystem to harmful impacts to the CP:
 Macroalgae and sea grasses are the major primary producers in coastal areas, forming the
base of the marine food chain. Kelp and rockweed are the dominant large structural
seaweeds in the LOMA, with rockweeds dominating the intertidal zone and kelps
dominating the subtidal zone in areas with appropriate hard stable substrate.
 Rockweed beds leave a cool, wet, protective blanket of vegetation when the tide goes out,
which prevents the intertidal animals from drying out. Many invertebrates, such as
urchins, periwinkles and amphipods, feed on the young plants, fragments that continually
break off, as well as on the mucous, bacteria and epiphytes (smaller attached plants)
found on the rockweed fronds.
 These vegetarians (herbivores) are themselves much sought after by fish, seabirds and
other hungry carnivores that forage among the fronds. At least 30 species of fish, 15
species of birds and scores of different invertebrates use the rockweed beds at some point
in their life cycle.
 The beds seem to be a critical nursery area for many species of fish, including several
commercially important ones such as pollock, herring and flounder. For instance, in
early May, young pollock, only a few centimetres in length, move shoreward to forage in
the seaweed "forest" as the tide rises, and retreat seaward as it falls. They eat the
abundant small animals hiding amongst the rockweeds and grow rapidly. Seabirds also
forage in the rockweed (Percy, J. A., 1996).
 Similarly, kelp forests provide important food resources for invertebrate grazers,
primarily sea urchins, and are also producers of suspended food for many filter-feeding
organisms, and provide habitat for a wide range of juvenile fish, shellfish and other
invertebrate species, and foraging areas for adult fish (Fisheries and Oceans Canada,
2008a; Fisheries and Oceans Canada, 2008b; Fisheries and Oceans Canada, 2008c).
 Marine vegetation such as kelp and rockweed increase the complexity of a habitat,
providing high quality refuge and feeding habitats, which are important features of high
quality nursery habitats (Borg, A., Phil, L., & Wennhage, H., 1997).
 In the northern areas of the LOMA, ice scour removes much of the intertidal seaweed
annually, but in southern areas and deeper water, large forests of these perennial
macrophytes provide food, shelter, spawning and nursery habitat and attachment sites for
a wide range of marine organisms.
 Even after they are torn loose from their rocky beds by the storms of autumn and winter,
these seaweeds continue to be valuable in the marine environment. The still living,
photosynthesizing fronds accumulate in large floating rafts that drift with the currents.
This jumble of vegetation teems with small marine animals seeking food and refuge,
including larval lobsters and fish. These in turn attract seabirds such as phalaropes and
terns, as well as larger fish (Percy, J. A., 1996).
 After drifting for weeks or months, the rafts wash ashore and pile up in long windrows at
the high tide mark. Sandflies, beach fleas, bacteria and fungi thrive in the dying
3



The small particles formed during decomposition are an important food for bottom
dwelling animals. The soluble material is a potent fertilizer that stimulates the production
of phytoplankton and other marine plants. Recent studies also suggest that some of the
colloidal organic compounds produced may be eaten by adult and larval scallops (Percy,
J. A., 1996).
Kelp and rockweed form complex ecosystems which provide important food, shelter and
refuge from predators for a wide range of marine species. (Score 9)
Kelp is listed as a structural species for the LOMA. (add 1 point)
Score 10
Sensitivity: (8+3+10)/3 = 7
Risk of Harm: 7 x 1.4 = 9.8
4
Certainty Checklist
Answer yes or no to all of the following questions. Record the number of NO’s to the 9
questions, and record certainty according to the scale provided below:
1
No’s = High certainty
2- 3 No’s = Medium certainty
>4
No’s = Low certainty
Y/N
N Is the score supported by a large body of information?
Y Is the score supported by general expert agreement?
Y Is the interaction well understood, without major information gaps/sources of error?
Y Is the current level of understanding based on empirical data rather than models,
anecdotal information or probable scenarios?
N Is the score supported by data which is specific to the region, (EBSA, LOMA, NW
Atlantic?
N Is the score supported by recent data or research (the last 10 years or less)?
N Is the score supported by long-term data sets (ten years or more) from multiple surveys
(5 years or more)?
Y Do you have a reasonable level of comfort in the scoring/conclusions?
N Do you have a high level of confidence in the scoring/conclusions?
Certainty Score: Low
For interactions with Low certainty, underline the main factor(s) contributing to the
uncertainty
Lack of comprehensive data
Lack of expert agreement
Predictions based of future scenarios which are difficult to predict
Other (provide explanation)
Suggest possible research to address uncertainty:
Better local data local data needs to be compiled on the cumulative impacts of dredging on
fish habitats.
5
Reference List
1. Borg, A., Phil, L., & Wennhage, H. (1997). Habitat Choice by Juvenile Cod
(Gadus morhua L.) on Sandy Soft Bottoms with Different Vegetation Types.
Helgoland Marine Research, 51, 197-212.
2. Fisheries and Oceans Canada. Marine Environmental Quality Atlas. 2005.
Ref Type: Unpublished Work
3. Fisheries and Oceans Canada. Cabbage Kelp, Species Profile Series, No. 15.
2008a. Ref Type: Pamphlet
4. Fisheries and Oceans Canada. Finger Kelp, Coastal Zone Species Profile Series,
No 14. 2008b. Ref Type: Pamphlet
5. Fisheries and Oceans Canada. Winged Kelp, Species Profile Series, No 13.
2008c. Ref Type: Pamphlet
6. Percy, J. A. The Seaweed Forest: Rockweed Harvesting in the Bay of Fundy.
Fundy Issues #4. 1996. Annapolis Royal, NS, The Clean Annapolis River
Project and Bay of Fundy Ecosystem Project.
Ref Type: Pamphlet
6
Structural habitat provided by rockweed and kelp within the PBGB LOMA
Fish plant effluent
Magnitude of Interaction
Areal extent:
 Kelp and rockweed are the dominant seaweeds in the subtidal and intertidal habitats
where appropriate hard substrates are available. Ice scour and sea urchin grazing cause a
natural cycle in the locations of seaweed beds, and therefore it is difficult to map the
changing distribution of these species, but all appropriate hard intertidal (rockweed) and
subtidal (kelp) substrates can be considered kelp and rockweed habitat. They readily
colonize available habitats, and may recolonize freshly dredged harbours if hard substrate
is made available.
 Fish plant effluent is discharged, largely untreated, from approximately 85 active fish
plants throughout the LOMA (Figure 1).
Figure 1. Fish plants (green symbols) operating within the LOMA (Fisheries and Oceans
Canada, 2005).

Since it is difficult to map the CP, we have based the score on the likelihood of overlap,
which is moderate.
Score 5
Contact:
 Kelp and rockweed beds utilize the entire water column in shallow areas, with the
holdfast anchoring them to the substrate, and the stipe and blades of the kelp or thallus of
the rockweed floating in the water column extending up to the water surface.
 Fish plant effluent generally forms a plume which dissipates through the water column,
and in low energy environments may accumulate on the bottom, smothering bottom
substrates. Oils may float to the surface.
 Contact is therefore 100%.
Score 10
1
Duration:
 Kelp and rockweed are perennial and occupy an area throughout the year, and at the same
time they actively colonized new sites every year.
 Fish plant effluent is also discharged continuously throughout the year. Most plants
operate year-round; other plants operate seasonally or based on fish supply.
 For continuous stressors, a score between 75-100% is selected, depending on the
persistence of the effluent in the environment.
 Fish plant effluent contains particles of fish, including fish oils, and blood, as well as
harmful chemical cleaners and disinfectants. Temperature and salinity changes associated
with high volumes of freshwater can also harmfully alter marine ecosystems. The
majority of these components are readily broken down and assimilated into the
environment, as long as they are not released in such large quantities that they overload
the assimilative capacity of the ecosystem.
 Since most components of fish plant effluent are not persistent we have selected a score
at the low end of the ‘continuous stressor’ range.
Score 7.5
Intensity:
 Fishing activity within the LOMA is considered high on a global scale (75-100%) and
has historically been a pillar of the regional economy.
 Although we do not have a global map of fish plants, much of the fish harvested in the
region is also processed here, with over 85 fish plants operating within the LOMA, and
we have therefore selected a score within the high range.
 Within the Atlantic Provinces, Newfoundland has the second highest number of fish
plants of any province, but the lowest per km of coastline, therefore we have selected a
score at the lower end of the high scale.
Score 7.5
Magnitude of Interaction: (5x10x7.5x7.5)/1000 = 2.8
Sensitivity
Sensitivity of the CP to acute impacts:
 Kelp and rockweed have a high nitrogen requirement and may benefit from inputs of
organic material, as long they are not excessive. Excessive nutrients can lead to algae
blooms in the water column, and excessive epiphyte growth on blades/thali, blocking out
light required for photosynthesis (Dr. Robert Hooper, Director, Bonne Bay Marine
Station, Memorial University of Newfoundland, Norris Point, NL, A0K 3VO, “pers.
comm.”).
 Other potentially harmful impacts included changes in water temperature, salinity, or
chemical characteristics, which could disrupt biochemical processes such as growth and
reproduction (Fisheries and Oceans Canada, 2008c; Fisheries and Oceans Canada,
2008d).
2


Since DFO water quality surveys conducted in Placentia Bay in nine relatively sheltered
areas (Lawn, St. Lawrence, Burin, Marystown, Baine Harbour, Arnold’s Cove, Ship
Harbour, Fox Harbour, and Northeast Arm Placentia) found no significant reduction of
water quality (pH, temperature, turbidity, dissolved oxygen, salinity or redox) near fish
plant outfalls compared to reference sites (Park, L., 2005), acute impacts from fish plant
discharge are likely low, except in localized areas where inputs are excessive.
Acute impacts are therefore considered to be low.
Score 2
Sensitivity of the CP to chronic impacts:
 Kelp and rockweed are widespread, perennial, and relatively resilient to damage, with
new growth developing either from the base of existing plants or by settlement of motile
reproductive cells (Fisheries and Oceans Canada, 2008b; Fisheries and Oceans Canada,
2008c). Rockweed is more dependent on regrowth of old plants (Fisheries and Oceans
Canada, 2008c). Localized changes in temperature and salinity near outfalls may lead to
impaired growth or reproductive failure, but since the effects of fish plant effluent are
localized, recruitment is not expected to be reduced significantly from this stressor.
 Chronic impacts are therefore considered to be low.
Score 1
Sensitivity of ecosystem to harmful impacts to the CP:
 Macroalgae and sea grasses are the major primary producers in coastal areas, forming the
base of the marine food chain. Kelp and rockweed are the dominant large structural
seaweeds in the LOMA, with rockweeds dominating the intertidal zone and kelps
dominating the subtidal zone in areas with appropriate hard stable substrate.
 Rockweed beds leave a cool, wet, protective blanket of vegetation when the tide goes out,
which prevents the intertidal animals from drying out. Many invertebrates, such as
urchins, periwinkles and amphipods, feed on the young plants, fragments that continually
break off, as well as on the mucous, bacteria and epiphytes (smaller attached plants)
found on the rockweed fronds.
 These vegetarians (herbivores) are themselves much sought after by fish, seabirds and
other hungry carnivores that forage among the fronds. At least 30 species of fish, 15
species of birds and scores of different invertebrates use the rockweed beds at some point
in their life cycle.
 The beds seem to be a critical nursery area for many species of fish, including several
commercially important ones such as pollock, herring and flounder. For instance, in
early May, young pollock, only a few centimeters in length, move shoreward to forage in
the seaweed "forest" as the tide rises, and retreat seaward as it falls. They eat the
abundant small animals hiding amongst the rockweeds and grow rapidly. Seabirds also
forage in the rockweed (Fisheries and Oceans Canada, 2008b; Percy, J. A., 1996).
 Similarly, kelp forests provide important food resources for invertebrate grazers,
primarily sea urchins, and are also producers of suspended food for many filter-feeding
organisms, and provide habitat for a wide range of juvenile fish, shellfish and other
3







Marine vegetation, such as kelp and rockweed, increase the complexity of a habitat,
providing high quality refuge and feeding habitats, which are important features of high
quality nursery habitats (Borg, A., Phil, L., & Wennhage, H., 1997).
In the northern areas of the LOMA, ice scour removes much of the intertidal seaweed
annually, but in southern areas and deeper water, large forests of these perennial
macrophytes provide food, shelter, spawning and nursery habitat and attachment sites for
a wide range of marine organisms.
Even after they are torn loose from their rocky beds by the storms of autumn and winter,
these seaweeds continue to be valuable in the marine environment. The still living,
photosynthesizing fronds accumulate in large floating rafts that drift with the currents.
This jumble of vegetation teems with small marine animals seeking food and refuge,
including larval lobsters and fish. These in turn attract seabirds such as phalaropes and
terns, as well as larger fish (Percy, J. A., 1996).
After drifting for weeks or months, the rafts wash ashore and pile up in long windrows at
the high tide mark. Sandflies, beach fleas, bacteria and fungi thrive in the dying
vegetable matter. They slowly decompose this natural compost heap into a brownish
sludge, rich in fertilizing nutrients. The decaying mass may be re-floated by subsequent
high tides, drifting elsewhere to strand and rot, again and again until it finally disappears
(Percy, J. A., 1996).
The small particles formed during decomposition are an important food for bottom
dwelling animals. The soluble material is a potent fertilizer that stimulates the production
of phytoplankton and other marine plants. Recent studies also suggest that some of the
colloidal organic compounds produced may be eaten by adult and larval scallops (Percy,
J. A., 1996).
Kelp and rockweed form complex ecosystems which provide important food, shelter and
refuge from predators for a wide range of marine species. (Score 9)
Kelp is listed as a structural species for the LOMA (add 1 point).
Score 10
Sensitivity: (2+1+10)/3 = 4.3
Risk of Harm: 2.8 x 4.3 = 12
4
Certainty Checklist
Answer yes or no to all of the following questions. Record the number of NO’s to the 9
questions, and record certainty according to the scale provided below:
1
No’s = High certainty
2- 3 No’s = Medium certainty
No’s = Low certainty
>4
Y/N
Y Is the score supported by a large body of information?
Y Is the score supported by general expert agreement?
N Is the interaction well understood, without major information gaps/sources of error?
Y Is the current level of understanding based on empirical data rather than models,
anecdotal information or probable scenarios?
Y Is the score supported by data which is specific to the region, (EBSA, LOMA, NW
Atlantic?
Y Is the score supported by recent data or research (the last 10 years or less)?
N Is the score supported by long-term data sets (ten years or more) from multiple surveys
(5 years or more)?
Y Do you have a reasonable level of comfort in the scoring/conclusions?
N Do you have a high level of confidence in the scoring/conclusions?
Certainty Score: Medium
For interactions with Low certainty, underline the main factor(s) contributing to the
uncertainty
Lack of comprehensive data
Lack of expert agreement
Predictions based of future scenarios which are difficult to predict
Other (provide explanation)
Suggest possible research to address uncertainty:
5
Reference List
1. Borg, A., Phil, L., & Wennhage, H. (1997). Habitat Choice by Juvenile Cod
(Gadus morhua L.) on Sandy Soft Bottoms with Different Vegetation Types.
Helgoland Marine Research, 51, 197-212.
2. Fisheries and Oceans Canada. Marine Environmental Quality Atlas. 2005.
Ref Type: Unpublished Work
3. Fisheries and Oceans Canada. Cabbage Kelp, Species Profile Series, No. 15.
2008a. Ref Type: Pamphlet
4. Fisheries and Oceans Canada. Finger Kelp, Coastal Zone Species Profile
Series, No 14. 2008b. Ref Type: Pamphlet
5. Fisheries and Oceans Canada. Knotted Wrack, Coastal Zone Species Profile
Series, No.16. 2008c. Ref Type: Pamphlet
6. Fisheries and Oceans Canada. Winged Kelp, Species Profile Series, No 13.
2008d. Ref Type: Pamphlet
7. Park, L. DFO water quality surveys conducted in Placentia Bay. 2005.
8. Percy, J. A. The Seaweed Forest: Rockweed Harvesting in the Bay of Fundy.
Fundy Issues #4. 1996. Annapolis Royal, NS, The Clean Annapolis River
Project and Bay of Fundy Ecosystem Project.
Ref Type: Pamphlet
6
Structural habitat provided by rockweed and kelp within the PBGB LOMA
Sewage
Magnitude of Interaction
Areal extent:
 Kelp and rockweed are the dominant seaweeds in the subtidal and intertidal habitats
where appropriate hard substrates are available. They form perennial beds, and spread
through the release of motile spores that swim until they find suitable habitat within
which to settle. Ice scour and sea urchin grazing cause a natural cycle in the locations of
seaweed beds, and therefore it is difficult to map the changing distribution of these
species, but all appropriate hard intertidal (rockweed) and subtidal (kelp) substrates can
be considered kelp and rockweed habitat.
 Sewage effluent is discharged, largely untreated, from coastal communities throughout
the LOMA (Fig. 1 below).
Figure 1. Sewage outfalls (coloured dots with red indicating highest discharge and yellow
lowest) discharging into coastal waters of the LOMA (Fisheries and Oceans Canada, 2005)


Outfalls are generally (but not always) sited in areas of relatively high flushing to ensure
that solids are dispersed, and these are frequently areas with hard substrate which are
preferred by kelp and rockweed.
Based on this information the overlap is estimated to be moderate.
Score 6
Contact:
 Kelp and rockweed beds utilize the entire water column, with the holdfast anchoring
them to the substrate, and the stipe and blades of the kelp or thallus of the rockweed
floating in the water column extending up to the water surface.
 Sewage effluent generally forms a plume which dissipates through the water column, and
in low energy environments may accumulate on the bottom, smothering bottom
substrates. Oils and other light components may float to the surface.
 Contact is therefore 100%.
Score 10
1
Duration:
 Kelp and rockweed are perennial and occupy an area throughout the year, and at the same
time they actively colonized new sites every year.
 Sewage effluent is also discharged continuously throughout the year for a score of 75100% depending on the persistence of the effluent in the environment.
 Sewage contains a wide variety of potentially harmful components including high levels
of nutrients, pathogens, debris such as toilet paper, plastic containers, condoms, tampons,
rags, and over 200 chemicals that are dumped into sewers by households, businesses, and
industries (Holmes, M. & Wristen, K., 1999). Natural hormones, commonly used drugs
such as birth control pills, antibiotics and pain killers and food ingredients such as
caffeine can reach significant concentrations in sewage effluent. Common products such
as shampoos, cleaners, bleach, drain cleaners and deodorants can contain metals,
endocrine disruptors and other acidic, caustic or toxic ingredients that pose a health risk
to aquatic organisms. Toxic household products such as solvents, paints, bleach,
pesticides, dyes, and oils are often disposed of through the sewer system, or enter the
sewer system through storm water collection systems. Temperature and salinity changes
associated with high volumes of freshwater can also harmfully alter marine ecosystems.
The majority of these components are readily broken down and assimilated into the
environment, as long as they are not released in such large quantities that they overload
the assimilative capacity of the ecosystem.
 Since most components of sewage are not persistent we have selected a score at the low
end of the range.
Score 7.5
Intensity:
 Sewage discharge is a function of the population density and the level of sewage
treatment/marine discharge. Human sewage is discharged into the LOMA from close to
100 communities with a combined population of around 295,000 people, largely
untreated.
 Although this seems significant, the population density within the LOMA is relatively
low by global standards, and since all major centers are expected to have implemented an
acceptable level of sewage treatment in the near future, we have selected a score in the
low range (0-25%).
Score 2
Magnitude of Interaction: (6x10x7.5x2)/1000 = 0.9
Sensitivity
Sensitivity of the CP to acute impacts:
 Kelp and rockweed have a high nitrogen requirement and may benefit from inputs of
organic material, as long they are not excessive. Excessive nutrients can lead to algae
blooms in the water column, and excessive epiphyte growth on blades/thali, blocking out
light required for photosynthesis.
2


Other potentially harmful impacts include changes in water temperature, salinity, or
chemical characteristics, which could disrupt biochemical processes such as growth and
reproduction. These processes are cued to a narrow range of water quality characteristics
(Fisheries and Oceans Canada, 2008b; Fisheries and Oceans Canada, 2008c). Since
sewage effluent is discharged in large quantities throughout many coastal areas of the
LOMA where kelp and rockweed grow, this could be a significant threat.
Since DFO water quality surveys conducted in Placentia Bay in nine relatively sheltered
areas (Lawn, St. Lawrence, Burin, Marystown, Baine Harbour, Arnold’s Cove, Ship
Harbour, Fox Harbour, and Northeast Arm Placentia) found no significant reduction of
water quality (pH, temperature, turbidity, dissolved oxygen, salinity or redox) near
sewage outfalls compared to reference sites (unpublished data, Oceans, 2005), acute
impacts from sewage discharge are likely low, except in localized areas where inputs are
excessive.
Score 2
Sensitivity of the CP chronic impacts:
 Kelp and rockweed are widespread, perennial, and relatively resilient to damage.
Changes in temperature and salinity may lead to impaired growth or reproductive failure,
but since the effects of sewage are localized, recruitment is not expected to be reduced
significantly from this stressor.
 Given the high energy environment common in coastal areas of the LOMA where the CP
thrives, lasting negative impacts are likely low, and the increased organic matter resulting
from sewage discharge may actually be beneficial in some areas.
Score 0
Sensitivity of ecosystem to harmful impacts to the CP:
 Macroalgae and sea grasses are the major primary producers in coastal areas, forming the
base of the marine food chain. Kelp and rockweed are the dominant large structural
seaweeds in the LOMA, with rockweeds dominating the intertidal zone and kelps
dominating the subtidal zone in areas with appropriate hard stable substrate.
 Rockweed beds leave a cool, wet, protective blanket of vegetation when the tide goes out,
which prevents the intertidal animals from drying out. Many invertebrates, such as
urchins, periwinkles and amphipods, feed on the young plants, fragments that continually
break off, as well as on the mucous, and bacteria and epiphytes (smaller attached plants)
found on the rockweed fronds.
 These vegetarians (herbivores) are themselves much sought after by fish, seabirds and
other carnivores that forage among the fronds. At least 30 species of fish, 15 species of
birds and scores of different invertebrates use the rockweed beds at some point in their
life cycle.
 The beds seem to be a critical nursery area for many species of fish, including several
commercially important ones such as pollock, herring and flounder. For instance, in
early May, young pollock, only a few centimetres in length, move shoreward to forage in
the seaweed "forest" as the tide rises, and retreat seaward as it falls. They eat the
3








Similarly, kelp forests provide important food resources for invertebrate grazers,
primarily sea urchins, and are also producers of suspended food for many filter-feeding
organisms, and provide habitat for a wide range of juvenile fish, shellfish and other
invertebrate species, and foraging areas for adult fish (Fisheries and Oceans Canada,
2008a; Fisheries and Oceans Canada, 2008b; Fisheries and Oceans Canada, 2008d)
Marine vegetation, such as kelp and rockweed, increase the complexity of a habitat,
providing high quality refuge and feeding habitats, which are important features of high
quality nursery habitats (Borg, A., Phil, L., & Wennhage, H., 1997).
In the northern areas of the LOMA, ice scour removes much of the intertidal seaweed
annually, but in southern areas and deeper water, large forests of these perennial
macrophytes provide food, shelter, spawning and nursery habitat and attachment sites for
a wide range of marine organisms.
Even after they are torn loose from their rocky beds by the storms of autumn and winter,
these seaweeds continue to be valuable in the marine environment. The still living,
photosynthesizing fronds accumulate in large floating rafts that drift with the currents.
This jumble of vegetation teems with small marine animals seeking food and refuge,
including larval lobsters and fish. These in turn attract seabirds such as phalaropes and
terns, as well as larger fish (Percy, J. A., 1996).
After drifting for weeks or months, the rafts wash ashore and pile up in long windrows at
the high tide mark. Sandflies, beach fleas, bacteria and fungi thrive in the dying vegetable
matter. They slowly decompose this natural compost heap into a brownish sludge, rich in
fertilizing nutrients. The decaying mass may be re-floated by subsequent high tides,
drifting elsewhere to strand and rot, again and again until it finally disappears (Percy, J.
A., 1996).
The small particles formed during decomposition are an important food for bottom
dwelling animals. The soluble material is a potent fertilizer that stimulates the production
of phytoplankton and other marine plants. Recent studies also suggest that some of the
colloidal organic compounds produced may be eaten by adult and larval scallops (Percy,
J. A., 1996).
Kelp and rockweed form complex ecosystems which provide important food, shelter and
refuge from predators for a wide range of marine species. (Score 9)
Kelp is listed as a structural species for the LOMA. (add 1 point)
Score 10
Sensitivity: (2+0+10)/3 = 4
Risk of Harm: 4x 0.9 = 3.6
4
Certainty Checklist
Answer yes or no to all of the following questions. Record the number of NO’s to the 9
questions, and record certainty according to the scale provided below:
1
No’s = High certainty
2- 3 No’s = Medium certainty
No’s = Low certainty
>4
Y/N
Y Is the score supported by a large body of information?
Y Is the score supported by general expert agreement?
N Is the interaction well understood, without major information gaps/sources of error?
Y Is the current level of understanding based on empirical data rather than models,
anecdotal information or probable scenarios?
Y Is the score supported by data which is specific to the region, (EBSA, LOMA, NW
Atlantic?
Y Is the score supported by recent data or research (the last 10 years or less)?
N Is the score supported by long-term data sets (ten years or more) from multiple surveys
(5 years or more)?
Y Do you have a reasonable level of comfort in the scoring/conclusions?
N Do you have a high level of confidence in the scoring/conclusions?
Certainty Score: Medium
For interactions with Low certainty, underline the main factor(s) contributing to the
uncertainty
Lack of comprehensive data
Lack of expert agreement
Predictions based of future scenarios which are difficult to predict
Other (provide explanation)
Suggest possible research to address uncertainty:
5
Reference List
1. Borg, A., Phil, L., & Wennhage, H. (1997). Habitat Choice by Juvenile Cod
(Gadus morhua L.) on Sandy Soft Bottoms with Different Vegetation Types.
Helgoland Marine Research, 51, 197-212.
2. Fisheries and Oceans Canada. Marine Environmental Quality Atlas. 2005.
3. Fisheries and Oceans Canada. Cabbage Kelp,Species Profile Series, No. 15.
2008a. Ref Type: Pamphlet
4. Fisheries and Oceans Canada. Finger Kelp, Coastal Zone Species Profile
Series, No 14. 2008b. Ref Type: Pamphlet
5. Fisheries and Oceans Canada. Knotted Wrack, Coastal Zone Species Profile
Series, No.16. 2008c. Ref Type: Pamphlet
6. Fisheries and Oceans Canada. Winged Kelp, Species Profile Series, No 13.
2008d. Ref Type: Pamphlet
7. Holmes, M. & Wristen, K. (1999). The National Sewage Report Card
(Number 2) Rating the Treatment Methods and Discharges of 21 Canadian
Cities United Fisherman and Allied Workers' Union, Local 24 and Georgia
Strait Alliance.
8. Percy, J. A. The Seaweed Forest: Rockweed Harvesting in the Bay of Fundy.
Fundy Issues #4. 1996. Annapolis Royal, NS, The Clean Annapolis River
Project and Bay of Fundy Ecosystem Project.
Ref Type: Pamphlet
6
Structural habitat provided by rockweed and kelp within the PBGB LOMA
Temperature change
Magnitude of Interaction
Areal extent:
 Kelp and rockweed are the dominant seaweeds in the subtidal and intertidal habitats
where appropriate hard substrates are available. They form perennial beds, and spread
through the release of motile spores that swim until they find suitable habitat within
which to settle. Ice scour and sea urchin grazing cause a natural cycle in the locations of
seaweed beds, and therefore it is difficult to map the changing distribution of these
species, but all appropriate hard, intertidal (rockweed) and subtidal (kelp) substrates with
moderate or high exposure can be considered kelp and rockweed habitat (Fisheries and
Oceans Canada, 2008a).
 Temperature change is a stressor which affects the entire globe, therefore areal extent is
considered to be 100%.
Score 10
Contact:
 The CP attaches to hard intertidal (rockweed) and subtidal (kelp) substrates and extend
up to the water surface. Rockweed is often exposed to the air at low tide, while kelp
fronds may lie on the sea surface.
 A global increase in air and sea temperature is predicted as a result of increased
atmospheric concentrations of greenhouse gases, with polar regions most affected (IPCC,
2007). Winter temperatures in Northern Canada are expected to rise by 40% more than
global averages. Within the PBGB LOMA, over the short term, this trend is less clear as
increasing Arctic temperatures and associated ice melt may result in increased advection
of cold fresh water by the Labrador Current. Such changes are difficult to predict, but
may include localized cooling and greater inter-annual variability (UNEP & UNFCCC,
2002), although a general increase in temperature and reduction in salinity is expected
throughout the water column (Frank, K. T, Perry, R. I., & Drinkwater, K. F., 1990).
 Surface waters (upper 30 metres) are heating up more rapidly than deeper waters, but
temperature changes have also been detected at substantial depths (UNEP & UNFCCC,
2002). On the Grand Banks, the area of bottom covered by sub-zero water has decreased
from >50% during the first half of the 1990s to near 15% during the past 3 years
(Fisheries and Oceans Canada, 2007).
 Since the entire water column will be affected by temperature change, with the highest
change in coastal areas where the CP grows, contact is considered to be 100%.
Score 10
Duration:
 Temperature is a constant, escalating stressor, so duration is considered to be 100%.
Score 10
1
Intensity:
 Halpern et al. (2008) have developed maps showing the global intensity of several
climate change stressors including changes in sea surface temperature (Halpern, B. S. et
al., 2008). These maps can be used to provide guidance in scoring the intensity of a
stressor in relation to maximum (Fisheries and Ocean Canada, 2007) intensity in a global
context, in accordance with the scale provided below. The figure below shows the
potential for ecological change in response to sea surface temperature based on the
frequency of temperature anomalies from 2000 to 2005, compared to 1985-1990,
normalized by the standard deviation:
Map colour
Red
Orange
Yellow
Light Blue
Dark Blue
Intensity
80-100%
60-80%
40-60%
20-40%
0-20%
Figure 1. Potential for ecological change in response to sea surface temperature, adapted
from (Halpern, B. S. et al., 2008).

Based on this information, the LOMA falls into the medium (yellow) range (40-60%) on
a global scale. We have selected the top score in this range due to the progressive nature
of the stressor (60%).
Score 6
Magnitude of Interaction: (10x10x10x6)/ 1000 = 6
Sensitivity
Sensitivity of the CP to acute impacts:
 Climate change models predict a general increase in water temperatures, particularly in
shallow coastal areas of the LOMA. A global increase in air and sea temperature is
predicted as a result of increased atmospheric concentrations of greenhouse gases, with
Polar Regions most affected (IPCC, 2007). Based on IPCC models, following the
precautionary principle, we will assume a maximum average increase in water
temperature of 0.3 - 0.4oC over the next ten years. Of greater concern is the predicted
increased in inter-annual variability (UNEP & UNFCCC, 2002), which could bring
record highs and lows and less predictability.
 Kelp and rockweed thrive in sub-arctic and temperature oceans, and are very sensitive to
temperature. These seaweeds grow most rapidly in the winter to spring, and growth slows
in the summer if water temperatures rise above 15oC-20oC, depending on the species.
Mass die-offs may occur as a result of high water temperature, with temperatures greater
2



than 15oC sufficient to cause death to some common species within the LOMA (Fisheries
and Oceans Canada, 2008a; Fisheries and Oceans Canada, 2008b; Fisheries and Oceans
Canada, 2008c).
Plants that are stressed by high temperature are less resilient, and less likely to recover
from other sources of harm including ice scour, sea urchin grazing and aquatic invasive
species. Summer water temperatures reach 20oC in coastal areas, and this is enough to
impair growth or even cause die-off of kelp, so any increase in average summer
temperature or unusually warm periods can cause widespread mortality of kelp and
rockweed.
Furthermore, water temperature is critical for the growth of Membranipora with
maximum growth occurring when water temperatures reach 15oC, usually in August in
most areas, with impact on the kelp peaking in November, and growth continuing until
December. Due to the warmer temperatures, kelp on the west and south coasts have
suffered major impacts as a result of this Membranipora, with kelp basically going from
a perennial to annual, while on the cooler northeast coast, Membranipora is present but
the level of harm to kelp is much lower. Climate change could potentially intensify the
growth of this harmful species. In 2006, as a result of a warm winter and early spring,
recruitment pulses began in June, while in 2007, following a colder winter and spring,
only one recruitment pulse was evident in August. Even a minor increase in temperature,
and greater inter-annual variation leading to frequent warm summers, may intensify the
devastating impacts of Membranipora on kelp and rockweed (Dr. Robert Hooper,
Director, Bonne Bay Marine Station, Memorial University of Newfoundland, Norris
Point, NL, A0K 3VO, pers. comm.).
Although the temperature change anticipated within the LOMA over the next ten years is
minimal (Drinkwater, K. F., 2005; Frank, Kenneth T., Perry, R. I., & Drinkwater, K. F.,
1990; IPCC, 2007), since kelp beds are already experiencing stress during warmer years
in some areas of the LOMA, acute sensitivity is considered moderate.
Score 5
Sensitivity of the CP to chronic impacts:
 Since climate change is a progressive stressor, temperature rise is likely to result in a
gradual change in the macroalgae assemblages.
 Some kelp and rockweed species are more sensitive than others and may prevail over
more sensitive species, but significant negative changes to the structural habitat provided
by the CP can be anticipated over the next century.
Score 8
Sensitivity of ecosystem to harmful impacts to the CP:
 Macroalgae and sea grasses are the major primary producers in coastal areas, forming the
base of the marine food chain. Kelp and rockweed are the dominant large structural
seaweeds in the LOMA, with rockweeds dominating the intertidal zone and kelps
dominating the subtidal zone in areas with appropriate hard stable substrate.
3









Rockweed beds leave a cool, wet, protective blanket of vegetation when the tide goes out,
which prevents the intertidal animals from drying out. Many invertebrates, such as
urchins, periwinkles and amphipods, feed on the young plants, fragments that continually
break off, as well as on the mucous, bacteria and epiphytes (smaller attached plants)
found on the rockweed fronds.
These vegetarians (herbivores) are themselves much sought after by fish, seabirds and
other carnivores that forage among the fronds. At least 30 species of fish, 15 species of
birds and scores of different invertebrates use the rockweed beds at some point in their
life cycle.
The beds seem to be a critical nursery area for many species of fish, including several
commercially important ones such as pollock, herring and flounder. For instance, in early
May, young pollock, only a few centimetres in length, move shoreward to forage in the
seaweed "forest" as the tide rises, and retreat seaward as it falls. They eat the abundant
small animals hiding amongst the rockweeds and grow rapidly. Seabirds also forage in
the rockweed (Percy, J. A., 1996).
Similarly, kelp forests provide important food resources for invertebrate grazers,
primarily sea urchins, and are also producers of suspended food for many filter-feeding
organisms, and provide habitat for a wide range of juvenile fish, shellfish and other
invertebrate species, and foraging areas for adult fish (Fisheries and Oceans Canada,
2008a; Fisheries and Oceans Canada, 2008b; Fisheries and Oceans Canada, 2008c)
Marine vegetation such as kelp and rockweed increase the complexity of a habitat,
providing high quality refuge and feeding habitats, which are important features of high
quality nursery habitats (Borg, A., Phil, L., & Wennhage, H., 1997).
In the northern areas of the LOMA, ice scour removes much of the intertidal seaweed
annually, but in southern areas and deeper water, large forests of these perennial
macrophytes provide food, shelter, spawning and nursery habitat and attachment sites for
a wide range of marine organisms.
Even after they are torn loose from their rocky beds by the storms of autumn and winter,
these seaweeds continue to be valuable in the marine environment. The still living,
photosynthesizing fronds accumulate in large floating rafts that drift with the currents.
This jumble of vegetation teems with small marine animals seeking food and refuge,
including larval lobsters and fish. These in turn attract seabirds such as phalaropes and
terns, as well as larger fish (Percy, J. A., 1996).
After drifting for weeks or months, the rafts wash ashore and pile up in long windrows at
the high tide mark. Sandflies, beach fleas, bacteria and fungi thrive in the dying
vegetable matter. They slowly decompose this natural compost heap into a brownish
sludge, rich in fertilizing nutrients. The decaying mass may be re-floated by subsequent
high tides, drifting elsewhere to strand and rot, again and again until it finally disappears
(Percy, J. A., 1996).
The small particles formed during decomposition are an important food for bottom
dwelling animals. The soluble material is a potent fertilizer that stimulates the production
of phytoplankton and other marine plants. Recent studies also suggest that some of the
colloidal organic compounds produced may be eaten by adult and larval scallops (Percy,
J. A., 1996).
4


Kelp and rockweed form complex ecosystems which provide important food, shelter and
refuge from predators for a wide range of marine species. (Score 9)
Kelp is listed as a structural species for the LOMA. (add 1 point)
Score 10
Sensitivity: (5+8+10)/3 = 7.7
Risk of Harm: 6 x 7.7 = 46.2
5
Certainty Checklist
Answer yes or no to all of the following questions. Record the number of NO’s to the 9
questions, and record certainty according to the scale provided below:
1
No’s = High certainty
2- 3 No’s = Medium certainty
>4
No’s = Low certainty
Y/N
N Is the score supported by a large body of information?
Y Is the score supported by general expert agreement?
Y Is the interaction well understood, without major information gaps/sources of error?
Y Is the current level of understanding based on empirical data rather than models,
anecdotal information or probable scenarios?
Y Is the score supported by data which is specific to the region, (EBSA, LOMA, NW
Atlantic?
Y Is the score supported by recent data or research (the last 10 years or less)?
Y Is the score supported by long-term data sets (ten years or more) from multiple surveys
(5 years or more)?
Y Do you have a reasonable level of comfort in the scoring/conclusions?
N Do you have a high level of confidence in the scoring/conclusions?
Certainty Score: Medium
For interactions with Low certainty, underline the main factor(s) contributing to the
uncertainty
Lack of comprehensive data
Lack of expert agreement
Predictions based of future scenarios which are difficult to predict
Other (provide explanation)
Suggest possible research to address uncertainty:
6
Reference List
1. Borg, A., Phil, L., & Wennhage, H. (1997). Habitat Choice by Juvenile Cod
(Gadus morhua L.) on Sandy Soft Bottoms with Different Vegetation Types.
Helgoland Marine Research, 51, 197-212.
2. Drinkwater, K. F. (2005). The response of Atlantic cod (Gadus morhua) to
future climate change. ICES Journal of Marine Science, 62, 1327-1337.
3. Fisheries and Ocean Canada (2007). Conservation Harvesting Plan (CHP),
Atlantic-wide for Mobile Gear Vessels 65-100', February 8, 2007 (unpublished)
Fisheries and Oceans Canada, Newfoundland & Labrador Region.
4. Fisheries and Oceans Canada (2007). 2006 State of the Ocean: Physical
Oceanographic Conditions in the Newfoundland and Labrador Region (Rep.
No. 2007/025). Canadian Science Advisory Secretariat Science Advisory
Report.
5. Fisheries and Oceans Canada. Cabbage Kelp,Species Profile Series, No. 15.
2008a. Ref Type: Pamphlet
6. Fisheries and Oceans Canada. Finger Kelp, Coastal Zone Species Profile Series,
No 14. 2008b. Ref Type: Pamphlet
7. Fisheries and Oceans Canada. Winged Kelp, Species Profile Series, No 13.
2008c. Ref Type: Pamphlet
8. Frank, K. T., Perry, R. I., & Drinkwater, K. F. (1990). Predicted Response of
Northwest Atlantic Invertebrate and Fish Stocks to CO 2 -Induced Climate
Change. Transactions of the American Fisheries Society, 119, 353-365.
9. Frank, K. T., Perry, R. I., & Drinkwater, K. F. (1990). Predicted Response of
Northwest Atlantic Invertebrate and Fish Stocks to CO2-Induced Climate
Change. Transactions of the American Fisheries Society, 119, 353-365.
10. Halpern, B. S., Walbridge, S., Selkoe, K. A., Kappel, C. V., Micheli, F.,
D'Agrosa, C., Bruno, J. F., Casey, K. S., Ebert, C., Fox, H. E., Fujita, R.,
Heinemann, D., Lenihan, H. S., Madin, E. M. P., Perry, M. T., Selig, E. R.,
Spalding, M., Steneck, R., & Watson, R. (2008). A Global Map of Human
Impact on Marine Ecosystems. Science, 319, 948-952.
11. IPCC (2007). A report of Working Group I of the Intergovernmental Panel on
Climate Change: Summary for Policymakers Cambridge, United Kingdom and
New York, NY, USA: Cambridge University Press.
7
12. Percy, J. A. The Seaweed Forest: Rockweed Harvesting in the Bay of Fundy.
Fundy Issues #4. 1996. Annapolis Royal, NS, The Clean Annapolis River
Project and Bay of Fundy Ecosystem Project. Ref Type: Pamphlet
13. UNEP & UNFCCC (2002). Climate Change Information Kit UNEP and
UNFCCC.
8
Structural habitat provided by rockweed and kelp within the PBGB LOMA
Membranipora (Lacey bryozoan)
Magnitude of Interaction
Areal extent:
 Kelp and rockweed are the dominant seaweeds in the subtidal and intertidal habitats
where appropriate hard substrates are available. They form perennial beds, and spread
through the release of motile spores that swim until they find suitable habitat within
which to settle. Ice scour and sea urchin grazing cause a natural cycle in the locations of
seaweed beds, and therefore it is difficult to map the changing distribution of these
species, but all appropriate hard intertidal (rockweed) and subtidal (kelp) substrates with
moderate to high exposure can be considered kelp and rockweed habitat (Fisheries and
Oceans Canada, 2008a; Fisheries and Oceans Canada, 2008c).
 Membranipora was first detected by MUN Scientist Bob Hooper in Bonne Bay in 2002,
and over the last 7 years has spread to all coastal areas of the LOMA (see Figure 1).
Figure 1. Distribution Map showing site where M. membranacea has been documented in
Newfoundland Waters (2006-2008) (McKenzie, C. H., Baines, T., Clarke, K., & Pennell, C.,
2009).

Since this invasive species grows on the CP, and has been found on every coastal area of
the LOMA where surveys have been conducted, areal extent is considered to be 100%.
1
Score 10
Contact:
 Kelp and rockweed appear to be the preferred substrates for Membranipora, therefore
contact is 100%.
Score 10
Duration:
 Kelp and rockweed species are perennial and occupy an area throughout the year. These
algae are highly sensitive to temperature. Growth is inhibited by temperatures above 1520oC depending on the species, and growth is most rapid in winter and spring (Fisheries
and Oceans Canada, 2008a; Fisheries and Oceans Canada, 2008c). The winged kelp is the
most sensitive, and water temperatures above 15oC often cause mass die-offs (Fisheries
and Oceans Canada, 2008d).
 Water temperature is critical for the growth of Membranipora with maximum growth at
water temperatures reaching 15oC, usually in August in most areas, with growth
continuing until December.
 Because both species are present year-round we have given duration a score of 100%, but
their contrasting growth periods will have implications for sensitivity elements.
Score 10
Intensity:
 Invasive species have transformed marine habitats around the world (Molnar, J. L. et al.,
2008). Global incidents of harmful alien species invasions have been mapped by Molnar
et al (2008) and are shown in Fig.2.
Figure 2. Number of Harmful Alien Species by Coastal Ecosystem (Molnar, J. L. et al.,
2008)
2



On a global scale, the LOMA has a moderate intensity of invasive species.
Membranipora is of European origin, but has spread to coastal marine ecosystems
throughout the world.
We have selected a high score within the moderate range since Membranipora is
widespread throughout the LOMA.
Score 7.5
Magnitude of Interaction: (10x10x10x7.5)/1000 = 7.5
Sensitivity
Sensitivity of the CP to acute impacts:
 Membranipora is an invasive colonial bryozoan which grows on kelp, rockweed,
eelgrass, and other marine plants, secreting a protective limestone covering which forms
a tough, white lace-like crust over the flexible, rubbery surface of the plant. The growth
on the kelp makes the normally flexible blades rigid resulting in the breaking of the blade
at the stipe or base, with no new growth occurring until the next year. In high energy
areas, or during storm surges, encrusted blades are far more prone to break off, and in
some areas this has lead to the removal of entire kelp beds.
 Membranipora is expected to have a significant impact on the structural habitat provided
by kelp and to a lesser degree rockweed, with implications for biodiversity and
recruitment of juvenile fish and shellfish, such as lobster, which utilize kelp beds as
nursery habitat.
 Water temperature is critical for the growth of Membranipora with maximum growth at
water temperatures reaching 15oC, usually in August in most areas, with growth peaking
in November, and continuing until December. As result, kelp on the west and south coast
have suffered major impacts as a result of this AIS, with kelp basically going from a
perennial to annual. On the Northeast coast Membranipora is present but the level of
harm to kelp is much lower.
 Mature kelp beds are being killed on the north coast of Newfoundland, while young and
mature kelp are affected on the south coast of the island.
 Membranipora is expected to have a significant impact on primary productivity,
biodiversity and recruitment of juvenile fish and shellfish, such as lobster, which utilize
kelp beds as nursery habitat.
 Sea urchins thrive on Membranipora infested kelp, but it puts a bad taste on the gonads,
which negatively affects their commercial value.
 Since major impacts are confined to the southern half of the LOMA, we have selected a
high score in the medium range.
Score 7
Sensitivity of the CP to chronic impacts:
 Mature kelp beds are being killed on the north coast of Newfoundland, while young and
mature kelp are affected on the south coast of the island.
 The impact on the kelp peaks in November, and the plants seem to be able to re-grow
during the winter, and so are able to recover. Kelp on the south coast has suffered major
3




Climate change could potentially intensify the growth of this harmful species. In 2006, as
a result of a warm winter and early spring, recruitment pulses began in June, while in
2007, following a colder winter and spring, only one recruitment pulse was evident in
August.
Recent scientific evidence suggests a link between the destructive power (or intensity) of
hurricanes and higher ocean temperatures associated with global climate change (Elsner,
J. B., Kossin, J. P., & Jagger, T. H., 2008). Kelp and rockweed thrive in high energy
environments, but severe storm events also increase the harmful effects of
Membranipora.
There is serious concern that another AIS will follow in its wake since the occurrence of
Membranipora in Nova Scotia has corresponded to the invasion of the subtidal by
Codium fragile (oyster thief). In areas where the kelp bed has been reduced or removed
by Membranipora, Codium has established itself, preventing kelp from returning (Green,
D., McKenzie, C., & Mouland, D., 2008).
Since impacts of Membranipora are likely to spread further north as a result of climate
change, and may work synergistically with Codium to prevent recovery of the CP,
chronic impacts are consider to be high.
Score 9
Sensitivity of ecosystem to harmful impacts to CP:
 Macroalgae and sea grasses are the major primary producers in coastal areas, forming the
base of the marine food chain. Kelp and rockweed are the dominant large structural
seaweeds in the LOMA, with rockweeds dominating the intertidal zone and kelps
dominating the subtidal zone in areas with appropriate hard stable substrate.
 Rockweed beds leave a cool, wet, protective blanket of vegetation when the tide goes out,
which prevents the intertidal animals from drying out. Many invertebrates, such as
urchins, periwinkles and amphipods, feed on the young plants, fragments that continually
break off, as well as on the mucous, bacteria and epiphytes (smaller attached plants)
found on the rockweed fronds.
 These vegetarians (herbivores) are themselves much sought after by fish, seabirds and
other carnivores that forage among the fronds. At least 30 species of fish, 15 species of
birds and scores of different invertebrates use the rockweed beds at some point in their
life cycle.
 The beds seem to be a critical nursery area for many species of fish, including several
commercially important ones such as pollock, herring and flounder. For instance, in early
May, young pollock, only a few centimetres in length, move shoreward to forage in the
seaweed "forest" as the tide rises, and retreat seaward as it falls. They eat the abundant
small animals hiding amongst the rockweeds and grow rapidly. Seabirds also forage in
the rockweed (Percy, J. A., 1996).
 Similarly, kelp forests provide important food resources for invertebrate grazers,
primarily sea urchins, and are also producers of suspended food for many filter-feeding
organisms, and provide habitat for a wide range of juvenile fish, shellfish and other
4







Marine vegetation, such as kelp and rockweed, increase the complexity of a habitat,
providing high quality refuge and feeding habitats, which are important features of high
quality nursery habitats (Borg, A., Phil, L., & Wennhage, H., 1997).
In the northern areas of the LOMA ice scour removes much of the intertidal seaweed
annually, but in southern areas and deeper water, large forests of these perennial
macrophytes provide food, shelter, spawning and nursery habitat, and attachment sites for
a wide range of marine organisms.
Even after they are torn loose from their rocky beds by the storms of autumn and winter,
these seaweeds continue to be valuable in the marine environment. The still living,
photosynthesizing fronds accumulate in large floating rafts that drift with the currents.
This jumble of vegetation teems with small marine animals seeking food and refuge,
including larval lobsters and fish. These in turn attract seabirds such as phalaropes and
terns, as well as larger fish (Percy, J. A., 1996).
After drifting for weeks or months, the rafts wash ashore and pile up in long windrows at
the high tide mark. Sandflies, beach fleas, bacteria and fungi thrive in the dying
vegetable matter. They slowly decompose this natural compost heap into a brownish
sludge, rich in fertilizing nutrients. The decaying mass may be re-floated by subsequent
high tides, drifting elsewhere to strand and rot, again and again until it finally disappears
(Percy, J. A., 1996).
The small particles formed during decomposition are an important food for bottom
dwelling animals. The soluble material is a potent fertilizer that stimulates the production
of phytoplankton and other marine plants. Recent studies also suggest that some of the
colloidal organic compounds produced may be eaten by adult and larval scallops (Percy,
J. A., 1996).
Kelp and rockweed form complex ecosystems which provide important food, shelter and
refuge from predators for a wide range of marine species. (Score 9)
Kelp is listed as a structural species for the LOMA. (add 1 point)
Score 10
Sensitivity: (7+9+10)/3 = 8.7
Risk of Harm: 7.5 x 8.7 = 65.3
5
Certainty Checklist
Answer yes or no to all of the following questions. Record the number of NO’s to the 9
questions, and record certainty according to the scale provided below:
1
No’s = High certainty
2- 3 No’s = Medium certainty
No’s = Low certainty
>4
Y/N
Y Is the score supported by a large body of information?
Y Is the score supported by general expert agreement?
N Is the interaction well understood, without major information gaps/sources of error?
Y Is the current level of understanding based on empirical data rather than models,
anecdotal information or probable scenarios?
Y Is the score supported by data which is specific to the region, (EBSA, LOMA, NW
Atlantic?
Y Is the score supported by recent data or research (the last 10 years or less)?
N Is the score supported by long-term data sets (ten years or more) from multiple surveys
(5 years or more)?
Y Do you have a reasonable level of comfort in the scoring/conclusions?
N Do you have a high level of confidence in the scoring/conclusions?
Certainty Score: Medium
For interactions with Low certainty, underline the main factor(s) contributing to the
uncertainty
Lack of comprehensive data
Lack of expert agreement
Predictions based of future scenarios which are difficult to predict
Other (provide explanation)
Suggest possible research to address uncertainty:
6
Reference List
1. Borg, A., Phil, L., & Wennhage, H. (1997). Habitat Choice by Juvenile Cod
(Gadus morhua L.) on Sandy Soft Bottoms with Different Vegetation Types.
Helgoland Marine Research, 51, 197-212.
2. Elsner, J. B., Kossin, J. P., & Jagger, T. H. (2008). The increasing intensity of
the strongest tropical cyclones. Nature, 455, 92-95.
3. Fisheries and Oceans Canada. Cabbage Kelp,Species Profile Series, No. 15.
2008a. Ref Type: Pamphlet
4. Fisheries and Oceans Canada. Finger Kelp, Coastal Zone Species Profile
Series, No 14. 2008b. Ref Type: Pamphlet
5. Fisheries and Oceans Canada. Knotted Wrack, Coastal Zone Species Profile
Series, No.16. 2008c. Ref Type: Pamphlet
6. Fisheries and Oceans Canada. Winged Kelp, Species Profile Series, No 13.
2008d. Ref Type: Pamphlet
7. Green, D., McKenzie, C., & Mouland, D. A Guide to Aquatic Invasive
Species. 2008. St. John's, Newfoundland. Ref Type: Pamphlet
8. McKenzie, C. H., Baines, T., Clarke, K., & Pennell, C. (2009). Aquatic
Invasive Species, Newfoundland and Labrador Region, 2008/09 Survey
Report: Report Summary NAFC: Science Branch, Fisheries and Oceans
Canada.
9. Molnar, J. L., Gamboa, R.L., Revenga, C., & and Spalding, M. (2008).
Assessing the global Threat of Invasive Species to Marine Biodiversity. Front
Ecol Environ, 6, 485-492.
10. Percy, J. A. The Seaweed Forest: Rockweed Harvesting in the Bay of Fundy.
Fundy Issues #4. 1996. Annapolis Royal, NS, The Clean Annapolis River
Project and Bay of Fundy Ecosystem Project.
Ref Type: Pamphlet
7
Structural habitat provided by rockweed and kelp within the PBGB LOMA
Codium fragile
Magnitude of Interaction
Areal extent:
 Kelp and rockweed are the dominant seaweeds in the subtidal and intertidal habitats
where appropriate hard substrates are available. They form perennial beds, and spread
through the release of motile spores that swim until they find suitable habitat within
which to settle. Ice scour and sea urchin grazing cause a natural cycle in the locations
of seaweed beds, and therefore it is difficult to map the changing distribution of these
species, but all appropriate hard intertidal (rockweed) and subtidal (kelp) substrates
can be considered kelp and rockweed habitat.
 Codium is an invasive macroalgae which grows rapidly on any hard surface including
rocks, boulders, cobble, wharves, boat hulls, fishing or aquaculture gear and wild or
cultured shellfish in the intertidal and subtidal marine or brackish waters. To date, the
oyster thief has not been detected within the LOMA, but since Membranipora has
heavily infested kelp beds within the LOMA, there is serious concern that the oyster
thief will follow in its wake since the occurrence of Membranipora in Nova Scotia
has corresponded to the invasion of the subtidal by Codium fragile.
 Based on the history of this invasive species in Nova Scotia, there is a high risk that
Codium will be introduced to sites within the LOMA within the next 10 years, and
once introduced, it may spread to adjacent sites, but is unlikely to reach wide
coverage over this timeframe. We have therefore given Codium a score within the
low range (0-25%).
Score 2.0
Contact:
 Both Codium and the CP grow in similar habitats in the tidal and subtidal zone.
 Codium does not attack kelp or rockweed directly, but may prevent their re-growth
following removal by other means including ice scour, sea urchin grazing or
Membranipora infestation, thereby significantly reducing their abundance.
 Vertical overlap is 100%.
Score 10
Duration:
 Codium and the CP are perennial and occupy an area throughout the year.
 Kelp grows rapidly in the winter to spring, and slows in the summer if water
temperatures rise above 15oC.
 Codium grows most rapidly in early winter when competition with other algae is
reduced. In summer, growth is reduced and the algae enter its reproductive phase.
 Since both species are present year-round we have given duration a score of 100%.
Their overlapping growth periods will have implications for sensitivity elements.
1
Score 10
Intensity:
 Invasive species have transformed marine habitats around the world (Molnar, J. L. et
al., 2008). Global incidents of harmful alien species invasions have been mapped by
Molnar et al., (2008) and are shown in Figure 1 below.
Figure 1. Number of Harmful Alien Species by Coastal Ecosystem (Molnar et al., 2008)



On a global scale, the LOMA has a moderate intensity of invasive species.
Codium is of Asian origin, but has spread to coastal marine ecosystem throughout the
world.
We have selected a score at the low end of the moderate range since Codium has not
yet been detected within the LOMA, but the Newfoundland Region is shown to be in
the yellow (low-medium) range for harmful alien species invasions.
Score 4
Magnitude of Interaction: (2x10x10x4)/1000 = 0.8
Sensitivity
Sensitivity of the CP to acute impacts:
 To date, the oyster thief has not been detected within the LOMA, but since
Membranipora has heavily infested kelp beds within the LOMA, there is serious
concern that the oyster thief will follow in its wake since the occurrence of
Membranipora in Nova Scotia has corresponded to the invasion of the subtidal by
Codium fragile.
 Codium does not attack kelp or rockweed directly, but may prevent their re-growth
following removal of the native seaweeds by other means including ice scour, sea
urchin grazing or Membranipora infestation thereby significantly reducing the
distribution and abundance of the CP.
2


In areas where the kelp bed has been reduced or removed by Membranipora, Codium
has established itself, preventing kelp from returning. Thus, by working together,
Membranipora and Codium have brought about what may be long-lasting change in
the subtidal ecosystem that could have negative effects on biodiversity and
commercial resource use, and there is concern that this may be repeated in
Newfoundland.
Because this AIS has not been detected in the LOMA or in the province, we have
selected a score in the low range for acute (short-term) impacts.
Score 2
Sensitivity of the CP to chronic impacts:
 Once Codium is established in an area formerly occupied by the rockweed or kelp,
the species are not able to re-establish, and this can dramatically alter the dynamics of
the coastal ecosystem as luxuriant kelp beds that formerly dominated the subtidal
zone are replaced with low-lying bush Codium stands (Green, D., McKenzie, C., &
Mouland, D., 2008).
 The resulting shift in algal dominance is associated with pronounced changes in
benthic habitat and community structure, with an overall decrease in biodiversity.
 This could result in significant negative impact on marine ecosystem structure and
function within the coastal zone of the LOMA, as well as significant economic loss,
since this invasive macroalgae grows rapidly on any hard surface including wharves,
boat hulls and wild or cultured shellfish in the intertidal and subtidal marine or
brackish waters. It is known to impair the growth of shellfish, foul fishing nets and in
heavily infested areas, large amounts of this seaweed have been known to wash up
and rot on beaches, making them unusable for recreation. (Green, D., McKenzie, C.,
& Mouland, D., 2008).
Score 8
Sensitivity of ecosystem to harmful impacts to the CP:
 Macroalgae and sea grasses are the major primary producers in coastal areas, forming
the base of the marine food chain. Kelp and rockweed are the dominant large
structural seaweeds in the LOMA, with rockweeds dominating the intertidal zone and
kelps dominating the subtidal zone in areas with appropriate hard stable substrate.
 Rockweed beds leave a cool, wet, protective blanket of vegetation when the tide goes
out, which prevents the intertidal animals from drying out. Many invertebrates, such
as urchins, periwinkles and amphipods, feed on the young plants, fragments that
continually break off, as well as on the mucous, bacteria and epiphytes (smaller
attached plants) found on the rockweed fronds.
 These vegetarians (herbivores) are themselves much sought after by fish, seabirds and
other hungry carnivores that forage among the fronds. At least 30 species of fish, 15
species of birds and scores of different invertebrates use the rockweed beds at some
point in their life cycle.
3









The beds seem to be a critical nursery area for many species of fish, including several
commercially important ones such as pollock, herring and flounder. For instance, in
early May, young pollock, only a few centimetres in length, move shoreward to
forage in the seaweed "forest" as the tide rises, and retreat seaward as it falls. They
eat the abundant small animals hiding amongst the rockweeds and grow rapidly.
Seabirds also forage in the rockweed (Percy, J. A., 1996).
Similarly kelp forests provide important food resources for invertebrate grazers,
primarily sea urchins, and are also producers of suspended food for many filterfeeding organisms, and provide habitat for a wide range of juvenile fish, shellfish and
other invertebrate species, and foraging areas for adult fish (Fisheries and Oceans
Canada, 2008a; Fisheries and Oceans Canada, 2008b; Fisheries and Oceans Canada,
2008c).
Marine vegetation such as kelp and rockweed increase the complexity of a habitat,
providing high quality refuge and feeding habitats, which are important features of
high quality nursery habitats (Borg, A., Phil, L., & Wennhage, H., 1997).
In the northern areas of the LOMA ice scour removes much of the intertidal seaweed
annually, but in southern areas and deeper water, large forests of these perennial
macrophytes provide food, shelter, spawning and nursery habitat and attachment sites
for a wide range of marine organisms.
Even after they are torn loose from their rocky beds by the storms of autumn and
winter, these seaweeds continue to be valuable in the marine environment. The still
living, photosynthesizing fronds accumulate in large floating rafts that drift with the
currents. This jumble of vegetation teems with small marine animals seeking food
and refuge, including larval lobsters and fish. These in turn attract seabirds such as
phalaropes and terns, as well as larger fish (Percy, J. A., 1996).
After drifting for weeks or months, the rafts of unattached rockweed and kelp wash
ashore and pile up in long windrows at the high tide mark. Sandflies, beach fleas,
bacteria and fungi thrive in the dying vegetable matter. They slowly decompose this
natural compost heap into a brownish sludge, rich in fertilizing nutrients. The
decaying mass may be re-floated by subsequent high tides, drifting elsewhere to
strand and rot, again and again until it finally disappears (Percy, J. A., 1996).
The small particles formed during decomposition are an important food for bottom
dwelling animals. The soluble material is a potent fertilizer that stimulates the
production of phytoplankton and other marine plants. Recent studies also suggest
that some of the colloidal organic compounds produced may be eaten by adult and
larval scallops (Percy, J. A., 1996).
Kelp and rockweed form complex ecosystems which provide important food, shelter
and refuge from predators for a wide range of marine species. (Score 9)
Kelp is listed as a structural species for the LOMA. (add 1 point)
Score 10
Sensitivity: (2+8+10)/3 = 6.7
Risk of Harm: 6.7x 0.8 = 5.4
4
Certainty Checklist
Answer yes or no to all of the following questions. Record the number of NO’s to the 9
questions, and record certainty according to the scale provided below:
1
No’s = High certainty
2- 3 No’s = Medium certainty
No’s = Low certainty
>4
Y/N
N Is the score supported by a large body of information?
Y Is the score supported by general expert agreement?
N Is the interaction well understood, without major information gaps/sources of error?
Y Is the current level of understanding based on empirical data rather than models,
anecdotal information or probable scenarios?
N Is the score supported by data which is specific to the region, (EBSA, LOMA, NW
Atlantic?
Y Is the score supported by recent data or research (the last 10 years or less)?
N Is the score supported by long-term data sets (ten years or more) from multiple surveys
(5 years or more)?
Y Do you have a reasonable level of comfort in the scoring/conclusions?
N Do you have a high level of confidence in the scoring/conclusions?
Certainty Score: Low
For interactions with Low certainty, underline the main factor(s) contributing to the
uncertainty
Lack of comprehensive data
Lack of expert agreement
Predictions based of future scenarios which are difficult to predict
Other (provide explanation)
Suggest possible research to address uncertainty:
5
Reference List
1. Borg, A., Phil, L., & Wennhage, H. (1997). Habitat Choice by Juvenile Cod
(Gadus morhua L.) on Sandy Soft Bottoms with Different Vegetation Types.
Helgoland Marine Research, 51, 197-212.
2. Fisheries and Oceans Canada. Cabbage Kelp, Species Profile Series, No. 15.
2008a. Ref Type: Pamphlet
3. Fisheries and Oceans Canada. Finger Kelp, Coastal Zone Species Profile
Series, No 14. 2008b. Ref Type: Pamphlet
4. Fisheries and Oceans Canada. Winged Kelp, Species Profile Series, No 13.
2008c. Ref Type: Pamphlet
5. Green, D., McKenzie, C., & Mouland, D. A Guide to Aquatic Invasive
Species. 2008. St. John's, Newfoundland. Ref Type: Pamphlet
6. Molnar, J. L., Gamboa, R.L., Revenga, C., & and Spalding, M. (2008).
Assessing the global Threat of Invasive Species to Marine Biodiversity. Front
Ecol Environ, 6, 485-492.
7. Percy, J. A. The Seaweed Forest: Rockweed Harvesting in the Bay of Fundy.
Fundy Issues #4. 1996. Annapolis Royal, NS, The Clean Annapolis River
Project and Bay of Fundy Ecosystem Project. Ref Type: Pamphlet
6
Summary Table: Structural habitat provided by Rockweed and Kelp within the
PBGB LOMA
Certainty
7.0
4.3
Risk
of
Harm
9.8
12.0
10
10
4.0
7.7
3.6
46.2
Med
Med
10
10
8.7
6.7
65.3
5.4
Med
Low
Key
Activity/Stressor
a
Dredging
Fish plant
Effluent
Sewage
Temperature
Change
Membranipora
Codium Fragile
4
5
10
10
6
6
1.4
7.5 7.5 2.8
8
2
3
1
10
10
6
10
10
10
7.5 2
10 6
0.9
6.0
2
5
0
8
10
2
10
10
10
10
7.5 7.5
4
0.8
7
2
9
8
c
d
i
MoI
as
cs
es
(a x c x d x i)
1000
S
(as+cs+es)
3
Cumulative CP Score 142.3
Low
Med