Download A Preliminary Ecosystem Model for the Reef Based Fishery

A Preliminary Ecosystem Model for the Reef Based Fishery resources of Jamaica.
Introduction
The aim of many ecological studies is to achieve sufficient understanding of the
interactions between organisms and their environments to be able to express
these relationships in precise numerical terms (R.V. Tait 1968). Mathematical
models may then be constructed from which predictions might be made. This
study focuses on the construction of steady state models using primarily the
software tools Ecopath with Ecosim, to describe the dynamics and interactions
between commercially important reef fish species, their environment and the
impact of fishing in the reef ecosystems of three Caribbean countries (Dominican
Republic, Jamaica and Tobago). Steady State models are by definition mass
balanced: the energy input and output of all living groups are balanced. It
assumes that the biomass of the elements of the system does not change from
one modeled time interval to the next (ref.), and is described by the following
equation:
Consumption = Production + Respiration + Unassimilated Food.
Steady state models require less data input in comparison with dynamic
simulation models, but still is useful for making summaries of the available data
and trophic flows in an ecosystem.
Ecopath with Ecosim (EwE) is an ecological software suite designed for
straightforward construction, parameterization and analyses of mass balanced
trophic models of aquatic and terrestrial ecosystems (V. Christensen et. al,
2005). The software suite has three components: Ecopath – a static mass
balanced snapshot of energy flow through an ecosystem; Ecosim – a time
dynamic simulation module for policy exploration; and Ecospace – a spatial and
temporal dynamic module primarily designed for exploring impact and placement
of protected areas.
Ecopath was first developed by J. J. Polovina (Polovina, 1993 in ..) based on a
simplification of T. Laevastus complex ecosystem biomass budget model for the
Bearing Sea (Laevastu & Larkins, 1981) by developing a system of simultaneous
linear biomass budget equations to balance biomass production and loss
(Polovina, 1984). The latest generation of the software suit, Ecopath with Ecosim
6, (www.ecopath.org) allows the estimation of numerous derived quantities on
species groups or whole system basis such as gross and net efficiencies, trophic
levels, food electivity, pathways and cycles involving any groups and ascendancy
(from Ulanowicz).
1
These computer models are constructed by defining a model area and time,
organizing species into functional groupings, and estimating the biological
characteristics of each grouping (Okey, 2002). Ecopath models and their defined
components are then ‘balanced’ in terms of mass or energy to gain insights into
ecosystem and its biotic components, and to obtain a whole-system view of the
biological community.
The parameters necessary for the construction of an Ecopath model are found in
the Ecopath master equation (ref):
Bi ⋅ (P/B)i ⋅ EEi = Yi + Σ Bj ⋅ (Q/B)j ⋅ DCji + BAi + NMi
where,
Bi and Bj = biomasses of prey (i) and predators (j) respectively;
P/Bi = production / biomass; equivalent to total mortality (Z) in most circumstances (Allen 1971);
EEi = ecotrophic efficiency; the fraction of the total production of a group that is utilized in the
system;
Yi = fisheries catch per unit area and time (i.e., Y = F*B);
Q/Bj = food consumption per unit biomass of j; and
DCji = contribution of i to the diet of j;
BAi = biomass accumulation of i (positive or negative);
NMi = net migration of i (emigration less immigration).
This equation expresses a balance between a group’s net production with all
sources of its mortality. It states that the net production of a functional group
equals the sum of (1) the total mass (or energy) removed by predators and
fisheries, (2) the group’s total natural senescence (i.e., flow to detritus), (3) the
net biomass accumulation of the group, and (4) the net migration of the group’s
biomass. Because the Ecopath model of the entire system is a set of these linear
equations solved simultaneously, the Ecopath routine can solve for any of the
four basic input parameters; B, P/B, Q/B, and EE (Christensen and Pauly 1992).
Previous Ecopath Models
While there are only a few Ecopath models that have examined or incorporated fisheries
such as Mohamed et al, (2005), Persad (2006) reported that there have been “a fair
number’ of studies done in which Ecopath (I & II) software has been used to model
trophic interactions in a variety of aquatic systems in both temperate and tropic latitudes.
North Sea Fishes
One model constructed by Christensen (1995), was based on the analysis of 55,000 fish
stomachs collected from the North Sea in 1981. For this model the North Sea was treated
as one strata with a total area of 570,000 km2 . That model included 29 groups, 15 of
which were fish groups, with 7 invertebrates, this latter made up of 6 groups of small
plankton and one detritus (DOM and POM) group. All weights and biomasses were
expressed in wet weight and on an areal basis to facilitate comparisons with other
systems. According to Persad (2006), previous studies had concluded that there was not
2
enough primary production to sustain the catches. Jones (1984) concluded that either the
primary production was underestimated, or the transfer of efficiencies between trophic
levels, were higher than 10% or both. Christensen (1995) on the other hand, concluded
that less than half of the primary production was required to sustain the consumption of
the system. He suggested that there could be a number of reasons for this reversal. Firstly,
the primary production had been increased to 2,300 g w.wt m-2 y-1., and feeding on
detritus had been included. Additionally, transfer efficiencies were estimated from
production and consumption rates, and were higher than 10% for many of the important
groups.
Table 1. Ecopath inputs of selected groups used for describing the North Sea Food Web
of 1981 (Christensen, 1995)
Group name
& number
16. Copepods
17. Euphausids
Biomass
g m-2
10
9.1
P/B
y-1
18
2.4
Q/B
y-1
60
16
Gross eff. EE
(P/Q)
0.30
0.93
0.15
0.95
Previous Caribbean Ecopath Models
Caribbean Coral Reefs
Opitz’s (1996) study, according to Persad (2006) tested whether it was possible to
construct what she called five thermodynamically balanced models of the trophic
interactions and organic matter transfer between compartments of a coral reef system..
The principal assumption of that study was that if such a model could be constructed,
then that would indicate that the coral reef was in some sort of steady state. Her study
also outlined the types of parameters needed fro input into ECOPATH II software. Opitz
found that the outputs of the model indicated the existence of short cycles, effectively
recycling organic matter within the reef system, with the large part of net primary
production being recycled directly to the detrital pool. Thus transfer efficiencies were
generally low. Summary statistics indicated that the system was at what Opitz termed an
intermediate stage of system maturity.
Venier & Pauly (1997) reported on the Looe Key National Marine Sanctuary in Florida,
which is an example of tropical, coastal system. This area is located approximately 13 km
off Big Pine Key, Florida, USA. The sanctuary is approximately 30 km2 and includes the
coral reef, surrounding coral, sand and seagrass habitats. A total of 9 fish groups and 11
non-fish groups were listed in their study. Persad (2006) extracted plankton-oriented data
for a table that she presented, which is reproduced balow as Table 2.
Table 2. Ecopath inputs of plankton groups used in the Looe Key, Florida, National
Marine Sanctuary Model.
3
Group name
Biomass
W wt
Km-2 y-1
Zooplanktom 40.0
Phytoplankton 30.0
P/B
y-1
Q/B
y-1
EE
65.0 165.0 0.96
70.0 0.98
They reported that the Looe key ecosystem is characterized by high ecotrophic efficiency
and high biomass values. This was achieved by a high degree of detritus recycling
(13.1%). They further described this ecosystem as highly mature.
Fisheries
Mohammed (2003) reported on a generic model for the eastern Caribbean marine
ecosystems. This comprehensive effort modeled the entire marine realm, from great
whales (cetaceans) to phytoplankton , and as far as it known, is the first attempt at such a
model for that region. This paper, based as it was on coralline areas (as well as others,
e.g. oceanic areas), was used to provide several of the input values for the Jamaica model.
For example, we extracted data on detritus, phytoplankton and zooplankton. These last
two values were used despite the research report of Persad (2006) who described and
modeled them for Discovery Bay in Jamaica. However, this small bay is not considered
as representative as the value calculated by Mohammed (2003).
Previous Jamaican Ecopath Models
Plankton
Persad (2006) used Ecopath with Ecosim (EwE) version 5.1 to model the planktonic
community in Discovery Bay, Jamaica (central north coast). This required the input of
the four basic parameters for each “functional group” as well as diet compositions for
each consumer. It was also possible to enter only three out of four basic parameters as
well as diet compositions and allow Ecopath to estimate the missing parameters.
Biomass in the habitat area
Persad (2006) defined the first parameter as ‘Biomass in the habitat area” (B) (Jm-2 ) and
defined it as ”the average biomass in the habitat area where the group occurs”, assuming
that an average value can be used to represent the biomass of each group (Christensen,
2005).
The biomass estimates for the zooplankton were estimated for data that was collected by
Persad (2006) who compiled the following table (Table 3) for all plankton groups.
4
Table 4. Original inputs for biomass and P/B rations for all plankton groups (Persad,
2006).
Plankton Group Avg. Biomass
J m-2
Carnivores
20,859
Calanoids
21,940
Cyclopoids
6,910
Harpacticoids
17
Larvaceans
1,036
Copepodites
2,195
Nauplii
1,005
Larvae
51,976
Phytoplankton
37,964.60
Detritus
136,976.86
P/B
Source
0.100
0.322
0.317
9.579
4.335
0.330
0.603
0.174
176.29
N/A
Persad, 2006
Ditto
Ditto
Ditto
Ditto
Ditto
Ditto
Ditto
Ditto
Ditto
Phytoplankton biomass and production estimates were obtained from Campbell (2000) as
shown in Table 3 and converted to the appropriate units by applying the conversion
1mgC phytoplankton = 11.40 calories (Platt & Irwin, 1973). An estimate for detritus
biomass was made with using an empirical equation described by Pauly (1993).
Trophic biology of reef fishes (Food habits)
In their major work on Cuban fishes, Claro et al;, (2001) reported that 138 species (38%)
consume fishes as their main food (fishes make up more than 50% of the food spectrum);
in 190 species (52%), fishes were present in the stomach contents. Benthic crustaceans
were eaten by 225 species and were the principal component in 28%. Fishes and
crustaceans were particularly important in the diets of snappers, jacks and grunts. Of the
other species summarized in their work, 41 species consume plankton (accounting for
more than 70% of their food in 31 of these species), 31 species are herbivores, and 5 are
detritivores (only the mullets {Mugilidae} were strictly detritivores. Planktivores include
the Clupeidae (herrings & sardines), Engraulidae (anchovies) and other less abundant
families. None of these is a strict phytoplanktivore. The Atlantic anchoveta (Cetengraulis
edulentus), however, has been reported to feed on large numbers of diatoms.
5
METHODOLOGY - JAMAICA
Habitat Area
This study will focus on reef areas of the North and South Shelf of Jamaica, and the
offshore banks identified as major fishing grounds for fishers from selected major fish
landing sites on the north coast and south coast respectively.
Figure showing Jamaica with shelf areas and offshore banks.
6
The majority of the seafloor on the shelf is seagrass and soft corals over sand and
limestone bedrock, with coralline growth concentrated at the edges (Halcrow, 1998;
Aiken & Kong, 2000). There are muddy areas near the estuaries of several relatively
large permanent rivers emptying at the south coast. Much of the south shelf is flat and
shallow with a mean depth of approximately 20 m and a maximum width of 25 km. The
north shelf is a narrow 1.6 km band all along the entire coastline, with deep (>300m)
water immediately offshore. The larger coral reefs are found on the eastern portion of the
south shelf and are of the fringing and sill types. There is deep water separating the island
from all the various oceanic banks, which is typical of this part of the Caribbean. The
edges of the shelf have a vertical or near-vertical profile into deep water (>300m) on all
sides (Munro, 1983). The total reef area is 1,240 km2. The island and the nine oceanic
banks have a total area of 4,170 km2 . An Exclusive Economic Zone established in 1996
has increased Jamaica’s total maritime area to 274, 000km2.
The fishing industry is primarily artisanal and small-scale, but is surprisingly diverse and
relatively complex (Halcrow, 1998). There are at least 15,000 to around 20,000 active
fishers and at least 3,500 registered fishing vessels operating from 168 mostly small
landing sites islandwide. The typical vessel is an open canoe (95% of all vessels) that
ranges in size from 4m (wooden dugouts) to > 18m (larger canoes fishing Pedro Bank
from the island).Most are outboard motor powered with a few larger decked industrial
vessels fishing conch and spiny lobster in season (CFRAMP, 2000). The main fishing
areas are on the island shelf and on the nine small oceanic banks. Pedro Bank is the
largest at 5,500km2 and is regularly fished A small group of sandy cays support several
dozen fishers who live there for most of the year. The main fishing gears are fish traps
(pots) and beach seine, tangle and gill nets, followed by hand lines, spearfishing and
some use of illegal explosives. Since 1980 there has been a steady increase in the number
of fishers employing nets of various kinds in an attempt to avoid widespread trap theft.
By 1996, net gears composed around 40% of all gears used (Fisheries Division, 1997).
Many fishers employ more than one gear (Espeut & Grant, 1990). North coast fishers are
mainly part-time while those on the south coast are mainly full-time. Marketing is
through a large diffuse higgler system.
Modelling Approach
Ecopath with Ecosim (EwE) versions 5 and 6 (Christensen and Walters, 2004; Pauly et
al., 2000; http://www.ecopath.org) were used to ensure mass balance of the model.
The preliminary model is a simplified representation of the Jamaican reef ecosystem with
the following conditions:
Representative species used, mainly of commercial interest or being part of the
landings from commercial fisheries.
Juveniles of species were ommited from the diet matrix therefore reducing the
need for multi-stanza groups.
7
-
Input to the model based largely on research of existing information. Particularly
important was the preliminary ecosystem model of the Eastern Caribbean
(Mohammed, 2003) and literature on the ecology of fish species in Cuba (Claro et
al., 2001).
The model was run several times to allow adjustment of parameters in achieving mass
balance. Where difficulties existed, the uncertain values of parameters (e.g., Biomass)
were omitted and an estimate made for another parameter (e.g., ecotrophic efficiency).
The model was considered balanced when: realistic estimates of the missing values of
ecotrophic efficiency for each functional group were calculated (i.e., EE < 1); and values
of the production consumption ratio were between 0.1 and 0.35 with the exception of top
predators for which lower values are expected (Christensen et al., 2004).
Model Inputs and construction (Opitz, 1996)
 Number of species (groups) considered in the model
 Biomass (Bi) for each species group or ecotrophic efficiency (EE) when biomass
is unknown
 Independent estimates of detritus biomass (D)
 Export (usually fisheries catch, including discard) for all exploited species
[groups]
 P/B ratio (usually Mi or Zi) for each species (group)
 Food consumption per unit biomass (Q/B) for each species (group)
 Diet composition DCij of each species (group)
 Independent estimates of net primary production (NPP)
Landings
The model represents an annual average situation of the Jamaican reef fisheries for the
period 1996 to 2005. Estimates of total landings by species were not readily available
from the Fisheries Division as there were inconsistencies in the raising procedure from
sample catches to total landings. Improvision was made by relying heavily on the sample
catches to determine proportionate catches for the species. Therefore the landings shown
for the functional groups reflects the relative weighting of catch composition from
landings but may not accurately show total landings for the species concerned. Total
landings for the period 1996 to 2005 as estimated by the Fisheries Division are shown in
Table (x).
Production: biomass ratio (P/B) (yr-1)
Under most conditions in fisheries, the P/B ratio is equal to the instantaneous rate of total
mortality used by fisheries biologists (Allen, 1971). That is, production according to
Christensen et al., (2005) includes fishery yield plus predation plus net migration plus
biomass change plus other mortality. The estimated input values for P/B are given in
Table 2.
Consumption: Biomass ratio (Q/B) (y-1):
Consumption is defined as the intake of food by a group over the time period considered
(Christensen, 2005). Consumption / biomass ratios Q/B are given in Table 2.
8
Ecotrophic Efficiency (EE) (proportion of 1):
The Ecotrophic efficiency (EE) is the fraction of production that is used by the system
(either passed up the food web, use for biomass accumulation, migration or export).
given in Table 2.
Diet Composition
For mass-balance to be attained, diet composition must be entered. The diet composition
of each group should add up to unity (1). Diet compositions were entered from various
literature sources (see Table 3 with descriptions of various functional groups and
species). A major source was Claro et al., (eds.) (2001) which examined Cuban marine
fish ecology. This is very close to Jamaica (< less than 160 km to north) . Table 7 shows
the inputs for the Diet Matrix, where predators are in columns and prey in rows (adapted
from Claro et al., (2001). Note further, that some inputs were from Klump (2005) which
examined the status of coral reefs after hurricane Ivan in 2004.
Biomass
Biomass values were obtained largely from information in the literature. Appendix II lists
the biomass values for the functional groups and the sources of the estimates. There were
two exceptions, S. barracuda and P. argus. The personal observations and experience of
the authors were used to estimate the density of barracuda at 7 individuals / km2.
Biomass was then estimated based on the average weight of an individual found in
commercial catches (Opitz..). Similarly for P. argus, it is the author’s experience that
spiny lobster abundance is approximately half that of queen conch. In the absence of any
other relevant data, this relationship was used as the best available estimate of biomass
for the species.
Functional Groups
The categorisation of the major functional groups was based on literature reports.
Especially illustrative were the classifications used in Mohammed 2003, and Pitcher et
al., 2002. The piscivorean species selected represents as best as possible the existing
trophic levels (Christensen, 1999), and were chosen based on the authors (Aiken)
knowledge of Jamaican reef fish ecology and the availability of data for the species. The
non-vertebrate groups follow primarily the southeast Caribbean model of Mohammed
(2003). Table 1 below lists the families and number of species represented according to
functional groups. Approximately 63 fin fish species are represented in the model. The
total list of species represented in the model may be found in Appendix 1.
9
Table 1. Functional Groups and Families Represented in Model
Group #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Functional Group
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Carnivorous Demersals
Medium Carnivorous Demersals
Large Herbivorous Demersals
Small Carnivorous Demersals
Parrotfishes
Cephalopods
Herrings & Small Pelagics
Small Herbivorous Demersals
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae & Seagrasses
Detritus
Families (Classification) Represented
Number of
Species
3
1
7
7
1
4
18
1
5
6
2
1
3
1
1
1
3
Delphinidae
Rhincodontidae
Scombridae
Sphyraenidae, Carangidae
Cheloniidae
Serranidae, Lutjanidae
Serranidae, Lutjanidae, Haemulidae, Balistidae
Scaridae
Holocentridae, Mullidae
Scaridae
Loliginidae, Octopodidae
Clupiedae
Acanthuridae
Mugilidae
Strombidae
Palinuridae
Penaeidae
10
Table 2. Ecopath input data for the 24 groups used in the model. P/B is production to biomass ratio; Q/B is consumption to
biomass ratio; E/E is ecotrophic efficiency; Catch represents the annual average for the period 1996 - 2005.
Group #
Biomass
P/B
Q/B
E/E
Catch
-2
-1
-1
-2
-1
Group Name
t km
year
year
t km yr
1
Dolphins
0.004
0.030
9.800
0.0000
2
Benthic / Reef Sharks
0.096
0.320
4.750
0.0018
3
Mackerels & Tunas
0.027
1.230
15.330
0.0719
4
Medium Pelagics
0.704
0.390
5.960
0.1860
5
Marine Turtles
0.004
0.150
3.500
0.750
0.0000
6
Large Demersal
0.840
5.610
0.800
0.1120
7
Medium Demersal
0.954
5.530
0.4930
8
Large Herbivorous Demersal
1.605
0.850
13.500
0.800
0.0028
9
Small Carnivorous Demersal
2.013
16.100
0.0642
10
Parrotfishes
13.104
5.830
25.340
0.800
0.2940
11
Cephalopods
2.340
12.730
0.900
0.0000
12
Herrings & Other Small Pelagics
3.471
23.610
0.2380
13
Small Herbivorous Demersal
14.859
5.000
33.390
0.1280
14
Mullets & Other Detritivores
7.094
3.033
20.220
0.2230
15
Gastropod Mullosks
1.422
0.530
4.420
0.1630
16
Spiny Lobsters
0.700
1.475
7.400
0.0677
17
Benthic Crustaceans
108.580
1.840
25.370
0.9940
18
Mulluscs and Worms
37.336
4.140
61.600
0.900
0.0000
19
Echinoderms
0.730
6.840
0.0000
20
Zoobenthic sessile animals
344.394
1.360
12.000
0.681
0.0000
21
Zooplankton
40.000
165.000
0.100
0.0000
22
Phytoplankton
70.000
0.0000
23
Algae, Seagrasses & Autotrophs
3483.865
12.760
0.000
0.0000
24
Detritus
37.892
0.0000
11
Table 3. Main dietary components for the main species in the consumer groups of the model
Group #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Prey \ Predator Group
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Carnivorous Fish
Medium Carnivorous Fish
Large Herbivorous Fish
Small Carnivorous Fish
Parrotfishes
Cephalopods
Herrings & Small Pelagics
Small Herbivorous Fish
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses & Autotrophs
Detritus
Diet
Fish, cephalopods, crustaceans and other invertebrates
Lobsters, other benthic invertebrates, mullets and other fish.
Fish, Cephalopods, mullosks, crustaceans and other invertebrates
Fish, Cephalopods, crustaceans and other invertebrates
Sponges, jellyfish, starfish, fish, urchins and crustaceans
Fish, crabs, other crustaceans and mullosks
Small fish, benthic invertebrates, cephalopods, mullosks and plankton
Seagrasses
Benthic crustaceans, mullosks and worms
Algae, seagrasses, sponges
Small fish, other mollusks and crustaceans
Copepods, shrimps, annelids, crabs and zooplankton
Algae and other autotrophs
Detritus, some algae and phytoplankton
Algae, seagrasses, and detritus
Mullosks and worms, benthic invertebrates, some seagrasses and detritus.
Detritus, and plankton
Plankton and detritus
Detritus
Plankton
Phytoplankton
Source
MarineBio.org., October 6, 2007.
FishBase October 6, 2007
Claro et al., 2001; FishBase October 6, 2007
Munro et al., 1983; Claro et al., 2001; Humann 1994.
Seaturtles.org, October 6, 2007
Claro et al., 2001 ; FishBase October 6, 2007.
Claro et al., 2001 ; FishBase October 6, 2007.
Claro et al., 2001
Claro et al., 2001
Claro et al., 2001
MarineBio.org., October 6, 2007; Kaplan, Eugene H., 1932.
Claro et al., 2001
Claro et al., 2001
Claro et al., 2001; FishBase October 6, 2007
Tewfick A., 1997
MarineBio.org., October 6, 2007.
Kaplan, Eugene H., 1932.
12
RESULTS - JAMAICA
Table 4 shows the input parameters for the 24 groups after balancing the model. For
Group 3 (Mackerels and tunas) the Q/B ratio seems high for this top predator. The result
is perhaps explained by the mortality co-efficients shown in Table 5, where mortality due
to fishing is higher than the explained total mortality for the group. At the root of the
problem is perhaps the low estimate of biomass in comparison to the annual average
catches for the Mackerels and Tunas (Table 4). The diet matrix for consumers for the
same run is presented in Table 6.
The flow diagramme for the Jamaica Reef fisheries model is shown in Figure 2. Trophic
groups are aligned with their trophic level (TL) as fractional integers (Christensen and
Pauly, 1992). Phytoplankton, Seagrasses and Detritus are located at the base of the food
web. Dolphins and large pelagics (Mackerels and Tuna group) are the top predators with
a TL of approximately 4. Nurse sharks occupy the same trophic level as large groupers
and snappers (the Large Demersals group) with a TL = 3.5, while both sit below
Barracudas and large jacks (the Medium Pelagics group) in the food web.
Crustaceans, molluscs and small herbivorous fish dominate the biomass or trophic flow.
Spiny lobsters are significant as both prey and predator.
A comparative analysis of fishing and predatory impacts (Figure 3 and Appendix V)
reveals that:
 Depletion of biomass due to fishing mortality was significant only for the top
predator groups: Sharks, Tuna, Medium Pelagics and Large Carnivorous fish.
 Predation mortality accounts for the highest losses consumer groups
 Fish groups impacting greatly on the ecosystem include Barracudas and large
Jacks (Group medium pelagics) and the Medium carnivorous species.
Table 7 shows the values respiration through the system while Table 8 shows the biomass
flow through the trophic levels. Although there are six discrete trophic levels observable
from the trophic aggregation routine, the magnitude of flows and biomasses in trophic
levels higher than TL III is insignificant compared with trophic levels I and II. In fact
almost 98% of biomass is explained by trophic levels I and II.
The primary production required to sustain harvest levels for all groups is shown in Table
9a while primary production values for consumption for all groups are shown in Table
9b. The results indicate that the primary production required to maintain all groups is
very low (PPR / Tot PP = 8.32%). Similarly the primary production required to sustain
the current level of catches from fishing is very low at 3.03% of total primary production.
13
Table 4. Ecopath input parameters for the 24 groups used in the mass balanced model. Trophic levels, P/Q ratios and values in bold were
estimated by the model. H A is habitat area; P/B, is production to biomass ratio; Q/B, is consumption to biomass ratio; E/E, is ecotrophic
efficiency; and P/Q, is production to consumption ratio.
Group
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Group Name
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Demersal
Medium Demersal
Large Herbivorous Demersal
Small Carnivorous Demersal
Parrotfishes
Cephalopods
Herrings & Other Small
Pelagics
Small Herbivorous Demersal
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses &
Autotrophs
Detritus
Trophic
Level
4.1
3.5
3.9
3.7
3.2
3.5
3.3
2.0
3.1
2.1
3.1
HA
(fraction)
0.6
1
0.5
1
1
1
1
1
1
1
1
Biomass
in H A
(t/km2)
0.004
0.096
0.079
0.704
0.004
0.180
1.722
1.605
0.955
13.104
0.839
Biomass
(t/km2)
0.002
0.096
0.040
0.704
0.004
0.180
1.722
1.605
0.955
13.104
0.839
P/B
( / year)
0.030
0.320
0.680
0.390
0.150
0.840
0.954
0.850
2.013
5.830
2.340
Q/B
( / year)
9.800
4.750
10.560
5.960
3.500
5.610
5.530
13.500
16.100
25.340
12.730
E/E
0.000
0.057
0.495
0.838
0.000
0.750
0.800
0.384
0.800
0.023
0.800
P/Q
0.003
0.067
0.064
0.065
0.043
0.150
0.173
0.063
0.125
0.230
0.184
3.0
2.0
2.0
2.0
3.0
2.1
2.2
2.0
2.2
2.0
1.0
1
1
1
1
1
1
1
1
1
1
1
0.552
14.859
7.094
1.422
0.700
108.580
37.336
3.098
344.394
57.838
1969.105
0.552
14.859
7.094
1.422
0.700
108.580
37.336
3.098
344.394
57.838
1969.105
3.471
5.000
3.033
0.530
1.475
1.840
4.140
0.730
1.360
40.000
70.000
23.610
33.390
20.220
4.420
7.400
25.370
61.600
6.840
12.000
165.000
0.000
0.900
0.033
0.055
0.220
0.183
0.100
0.091
0.900
0.071
0.681
0.100
0.147
0.150
0.150
0.120
0.199
0.073
0.067
0.107
0.113
0.242
1.0
1.0
1
1
3483.865
37.892
3483.865
37.892
12.760
0.000
0.019
0.020
14
Table 5. Mortality co-efficients for the 24 functional groups
Group
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Group Name
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Demersal
Medium Demersal
Large Herbivorous Demersal
Small Carnivorous Demersal
Parrotfishes
Cephalopods
Herrings & Other Small Pelagics
Small Herbivorous Demersal
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses & Autotrophs
Prod./biom
(=Z)
0.030
0.320
0.680
0.390
0.150
0.840
0.954
0.850
2.013
5.830
2.340
3.471
5.000
3.033
0.530
1.475
1.840
4.140
0.730
1.360
40.000
70.000
12.760
`=
Fish.
Mort.
Rate
0.000
0.018
1.820
0.264
0.000
0.623
0.286
0.002
0.067
0.022
0.000
0.431
0.008
0.031
0.115
0.097
0.009
0.000
0.000
0.000
0.000
0.000
0.000
` + Pred.
Mort.
Rate
0.000
0.000
0.059
0.063
0.000
0.007
0.477
0.325
1.543
0.112
1.872
2.693
0.157
0.136
0.002
0.173
0.174
0.377
0.657
0.096
27.240
7.000
0.248
`+
Biomass
Acc. Rate
0
0
-2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
` + Net
Migration
Rate
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
` + Other
Mort.
Rate
0.030
0.302
0.344
0.063
0.150
0.210
0.191
0.523
0.403
5.695
0.468
0.347
4.835
2.866
0.414
1.205
1.657
3.763
0.073
1.264
12.760
63.000
12.512
15
Table 6. Diet composition of predators included in the ecosystem model representing the reef fisheries of Jamaica. Numbers represent the fraction of the food intake in weight.
Group Prey \ Predator Group
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Carnivorous Fish
Medium Carnivorous Fish
Large Herbivorous Fish
Small Carnivorous Fish
Parrotfishes
Cephalopods
Herrings & Small Pelagics
Small Herbivorous Fish
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses & Autotrophs
Detritus
Import
TOTAL
1
2
0
0
0.1
0.1
0
0.05
0.15
0.05
0
0
0.1
0.2
0
0
0.05
0.1
0.1
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0.1
0
0
0
0.15
0
0
0.15
0
0.15
0.2
0.15
0.1
0
0
0
0
0
0
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.1 0.15
0 0.1
0
0 0.1
0 0.1
0
0 0.1 0.05 0.1 0.1
0 0.1
0 0.1 0.1
0.2 0.2
0 0.1 0.05
0.4 0.2
0
0 0.05
0 0.05 0.05 0.1 0.1
0 0.1
0
0 0.05
0
0 0.1
0
0
0
0
0 0.05
0
0.2
0 0.1 0.25 0.25
0
0 0.1 0.1 0.15
0
0 0.1
0 0.1
0
0 0.5
0
0
0
0
0
0 0.05
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.6
0.4
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.1
0
0
0.9
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0.1
0
0
0
0.5
0.4
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.1
0.3
0.6
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.6
0.4
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.3
0.4
0.2
0
0
0
0.1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.1
0
0
0.9
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.2
0.4
0
0.4
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.2
0.8
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
1
16
Figure 2. Trophic flows between functional groups. Diameter of circles represent relative biomass, while lines show diet and
biomass flow.
17
Figure 3. Mixed trophic impacts in the Jamaica reef ecosystem (1996 – 2005). The figure shows direct and indirect impacts
caused by each group in the system (impacting groups; on the Y axes) on the other living groups (impacted groups; X axes).
Positive impacts are shown above the base line, while negative below. The impacts are relative but comparable between groups.
18
Table 7. Respiration
Group
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Group Name
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Demersal
Medium Demersal
Large Herbivorous Demersal
Small Carnivorous Demersal
Parrotfishes
Cephalopods
Herrings & Other Small Pelagics
Small Herbivorous Demersal
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses & Autotrophs
Respiration
(t/km2/yr)
0.019
0.334
0.307
3.082
0.011
0.655
5.974
15.970
10.374
189.248
6.579
8.512
322.619
93.236
4.275
3.112
2003.953
1685.347
14.689
2837.807
5321.086
0.000
0.000
Assimilation
(t/km2/yr)
0.019
0.365
0.334
3.357
0.011
0.806
7.617
17.334
12.296
265.644
8.542
10.428
396.914
114.753
5.028
4.144
2203.740
1839.918
16.950
3306.183
7634.602
Respiration
/
Assimilation
0.996
0.916
0.920
0.918
0.946
0.813
0.784
0.921
0.844
0.712
0.770
0.816
0.813
0.812
0.850
0.751
0.909
0.916
0.867
0.858
0.697
Production
/
Respiration
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Respiration /
Biomass
( / year)
7.810
3.480
7.768
4.378
2.650
3.648
3.470
9.950
10.867
14.442
7.844
15.417
21.712
13.143
3.006
4.445
18.456
45.140
4.742
8.240
92.000
19
Table 8. Biomass flow through the Trophic Levels. Biomass expressed in t/km2
Flow to
Trophil Level / Flow
Import
Consumption by
Export
Detritus
IX
0
0
0
VIII
0
0
0
VII
0
0
0
VI
0.0002
0.0016
0.0049
V
0.0222
0.0401
0.1523
IV
0.6797
0.3385
5.09
III
16.3057
0.9764
468.4289
II
1637.57
1.6778
5152.814
I
0
18156.65
169761.3
167643.8
Sum
0
19811.23
169764.4
173270.3
Extracted to break
cycles
Input TL II+ (not in
throughput)
Total throughput
Respiration
0
0
0.0001
0.0162
0.4717
10.2402
1151.87
11364.59
0
12527.19
Throughput
0
0
0.0002
0.0229
0.6863
16.3484
1637.581
18156.65
355561.8
375373.1
0
0
375373.1
20
Table 9. Primary production required for harvest of all groups
Group #
2
3
4
6
7
8
9
10
12
13
14
15
16
17
Group Name
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Large Demersal
Medium Demersal
Large Herbivorous Demersal
Small Carnivorous Demersal
Parrotfishes
Herrings & Other Small Pelagics
Small Herbivorous Demersal
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Total
No. of Paths
48
81
46
54
26
1
5
3
1
1
3
2
7
2
280
TL
35
4496.87
4980.65
1178.97
2244.37
0.04
79.83
33.13
9.81
0.82
0.59
0.82
44.33
8.3
13113.55
PPR (Det)
13.95
1159.72
1193.52
311.3
504.07
0
51.76
0
0
0
0.89
0.54
22.27
12.33
3270.36
PPR
48.96
5656.59
6174.17
1490.27
2748.44
0.04
131.59
33.13
9.81
0.82
1.49
1.36
66.6
20.64
16383.91
PPR / Tot PP
(%)
0.01
1.59
1.74
0.42
0.77
0
0.04
0.01
0
0
0
0
0.02
0.01
4.61
PPR / u.
Catch
0.08
0.22
0.09
0.04
0.02
0
0.01
0
0
0
0
0
0
0
0.02
PPR (PP)
420.03
610.97
1679.91
7352.08
3.5
1588.44
7477.39
21.67
2389.66
8609.89
1786.53
78.96
496.14
57.38
3.77
675.72
1668.58
3706.18
0
8312.79
9543.25
PPR (Det)
109.35
243.57
433.24
1761.79
1.01
419.42
1679.36
0
1549.2
0
943.35
0
0
86.06
2.51
339.49
2479.21
919.96
21.19
0
0
PPR /
PPR / Tot PP
PPR
Consumption Consumption
(%)
529.37
0.02
22546.74
0.15
854.54
0.46
1873.99
0.24
2113.16
0.42
5066.07
0.59
9113.87
4.2
2172.12
2.56
4.51
0.01
321.85
0
2007.86
1.01
1992.34
0.56
9156.75
9.52
961.75
2.58
21.67
21.67
1
0.01
3938.86
15.37
256.27
1.11
8609.89
332.06
25.93
2.42
2729.88
10.68
255.67
0.77
78.96
13.04
6.06
0.02
496.14
496.14
1
0.14
143.44
143.44
1
0.04
6.29
6.29
1
0
1015.21
5.18
195.99
0.29
4147.79
2754.68
1.51
1.17
4626.14
2299.9
2.01
1.3
21.19
21.19
1
0.01
8312.79
4132.73
2.01
2.34
9543.25
9543.25
1
2.68
19811.23
PPR / u.
Biomass
0.62
0.03
0.15
0.04
0
0.03
0.01
0
0.01
0
0.01
0
0
0
0
0
0
0
0
0
0
PPR (PP)
3.5
3.95
3.75
3.46
3.29
2
3.14
2.12
3
2
2
2
3.01
2.1
2.59
Catch
0
0.07
0.19
0.11
0.49
0
0.06
0.29
0.24
0.12
0.22
0.16
0.07
0.99
3.03
PPR / Catch
27817
78673.02
33194.46
13306.01
5574.93
15.88
2049.68
112.7
41.2
6.68
6.67
8.34
983.26
20.76
5399.4
Table 9 continued. Primary production required for consumption of all groups
Group #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Group Name
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Demersal
Medium Demersal
Large Herbivorous Demersal
Small Carnivorous Demersal
Parrotfishes
Cephalopods
Herrings & Other Small Pelagics
Small Herbivorous Demersal
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Total
No. of Paths
226
48
81
46
16
54
26
1
5
3
6
1
1
3
2
7
2
3
1
2
1
535
TL
4.06
3.5
3.95
3.75
3.19
3.46
3.29
2
3.14
2.12
3.13
3
2
2
2
3.01
2.1
2.2
2
2.2
2
21
DISCUSSION
Objective and Assumptions
The initial objective of the study was to construct ecosystem models for three
countries within the Caribbean eco-region as part of (contribution to) the ECOST
project. This resulted in models being constructed for Jamaica and the
Dominican Republic, and a previous model for the Eastern Caribbean done by
Elizabeth Mohammed being re-presented. Although recent reports have
analysed trophic relationships for planktonic organisms in Jamaica (Persad,
2006), this is the first ecosystem model applied to the fisheries of Jamaica.
Similarly, base on the lack of any report in the literature available to the authors
and from personal communication with the authorities in the Dominican Republic,
it would seem also that this effort represents the first ecosystem model of the
fisheries in that country. In the case of Tobago, the model presented is based on
the generic ecosystem model of the South east Caribbean by Elizabeth
Mohammed (Mohammed, 2003).
In these models we assumed steady – state and massed balanced conditions for
the eco-region for annual averages over 10 and 5 years up to 2005 for Jamaica
and the Dominican Republic respectively. The Eastern Caribbean model
represents the annual average for 1999. Intra-annual variability in the systems
(Strub et al., 1998) was not included in the modeling due to lacking estimates of
the required monthly and/or seasonal input data. It was also assumed that the
basic reef ecology is similar for all three countries in terms of species
composition and trophic dynamics (reference). The differentiating factor between
the three models described would have been the impact of fishing on the
ecosystems.
General characteristics of the Caribbean ecosystem
Highlights of each and comparisons between models
The model assumed the same basic community structures and pathways
between groups. The difference between the models was the impact of fishing on
the productivity of the target species and associated species groups along the
trophic pathways. For example,
Model Limitations
Information about ecosystems within the Caribbean region is generally limited
and uncertain, and this constraint limits the accuracy of the ecosystem models
produced. As much as possible, data uncertainty and estimated ranges for input
22
parameters were documented to allow and guide users towards appropriate
interpretation of the model results.
Another main limitation about Ecopath with Ecosim relates to the scale at which
ecosystems are being examined. Biotic components of the models presented are
generally combined into larger aggregate groups. This approach gives us a
broad view of the systems with the premise that the interaction of these broad
ecosystem components in dynamic simulations will represent the interaction of
real ecosystem components because enough population and energetic
information exists on this broad scale of examination to characterize the
mechanisms of interest (Okey and Mahmoudi editors, 2002). However,
ecosystem processes that that occur on micro-scales have fundamental
importance to broader scale ecosystem properties and structure. The lack of
explicit assessment of these smaller processes does not however imply that they
are excluded from consideration given that Ecopath parameters, and models
implicitly integrate micro-scale processes(Okey, 2002). Several of these
limitations due to scale are discussed by Christensen and Walters (2000) and
include:
• Incorrect assessment of predation impacts on rare prey;
• Trophic mediation effects (e.g., biogenic habitat effect);
• Underestimates of predation vulnerabilities;
• Non-additivity in predation rates due to shared foraging arenas;
• Temporal variation in species-specific habitat factors.
A further caution is that several problems do arise as a consequence of
aggregating groups in Ecopath especially when the number of species in the
model system is very large (Mackinson, 2002) as is the case for the three
Caribbean models. Some of these difficulties included:
(i) Fishing mortality is overestimated in Ecopath when functional groups are
composed of several species, for which catch data exists for all, but biomass
estimates do not. Since Ecopath determines F as F=C/B, an underestimated
biomass will result in an overestimated F(Mackinson, 2002). This problem was
apparent for five groups in the Jamaica and Dominican Republic models: Large
Demersal fish, Medium Demersal fish, Small Carnivorous fish, Cephalopods and
Herrings and other Small Pelagics. By providing reasonable estimates of EE, we
allowed the model to generate estimates of Biomass for the groups (Tablexx).
However, further work should be done to estimate more accurately the biomass
of the species within the aggregations.
(ii) Within the group Medium Pelagics (table x) fishing mortality for the Barracuda
tended to be underestimated. Mackinson (in xx 2002) found this phenomenomto
be particularly true for species within functional groups that comprise of many
species, of which only several might be fished. Essentially, important species that
may have a high fishing mortality are represented with lower mortalities in the
23
aggregated group. The consequence in Ecosim is that the groups will look as if
they can sustain a much higher fishing mortality than they really can.
24
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Pauly, D., V. Christensen, and C. Walters, 2000. Ecopath, Ecosim, and Ecospace as tools
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of British Columbia, Fisheries Centre, Vancouver, Canada and ICLARM, Penang, Malaysia, 131
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Pauly, D., V. Christensen, and C. Walters. 2000. Ecopath, Ecosim, and Ecospace as tools for
evaluating ecosystem impact of fisheries. ICES Journal of Marine Science 57: 697-706.
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to French Frigate Shoals. Coral Reefs 3:1-11.
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patterns in trophic relationships of exploited ecosystems, with emphasis on the impacts of marine
protected areas. Ecosystems 2:539-554.
26
Appendix I. Detailed list of species used in the Ecosystem model of the Jamaica reef
fisheries
Group #
Functional Group
Name of Species
Common
Scientific
1
Dolphins
Bottlenose Dolphin
Pan Tropic Spotted Dolphin
Atlantic Spotted Dolphin
Tursiops truncatus
Stenella attenuata
S. frontalis
2
Benthic / Reef Sharks
Nurse shark
Ginglymostoma cirratum
3
Mackerels & Tunas
Wahoo
King mackerel
Cero mackerel
Yellofin tuna
Bluefin tuna
Skipjack
Blackfin tuna
Acanthocybium solandri
Scomberomorus cavalla
Scomberomorus regalis
Thunnus albacares
Thunnus thynnus
Katsuwonus pelamis
Thunnus atlanticus
4
Medium Pelagics
Great Barracuda
Bar Jack
Black Jack
Crevalle Jack
Horse eye Jack
Yellow Jack
Lookdown
Sphyraena barracuda
Caranx ruber
C. lugubris
C. hippos
C. latus
C. bartholomaei
Selene vomer
5
Marine Turtles
Hawksbill turtle
Eretmochelys imbricata
6
Large Carnivorous Fish
Nassau grouper
Tiger grouper
Yellowfin grouper
Dog snapper
Epinephelus striatus
Mycteroperca tigris
Mycteroperca venenosa
Lutjanus jocu
7
Medium Carnivorous Fish
Rock hind
Red Hind
Graysby
Coney
Red Snapper
Yellowtail Snapper
Mahogany Snapper
Lane Snapper
Grey Snapper
Blue Striped
Caesar
French
Smallmouth
Spanish
Striped
White
Grey Triggerfish
Queen Triggerfish
Epinephelus adscensionis
Epinephelus guttatus
Cephalopholis cruentatus
Epinephelous fulvus
Lutjanus purpurieus
Ocyurus chrysurus
Lutjanus mahogoni
L. synagris
L. griseus
Haemulon sclurus
H. carbonarium
H. flavolineatum
H. chrysargyreum
H. macrostomum
H. striatum
H. plumierii
Balistes capriscus
Balistes vetula
27
Group
#
Functional Group
Common
Blue parrotfish
Name of Species
Scientific
Scarus coeruleus
8
Large Herbivorous Fish
9
Small Carnivorous Fish
Longspine squirrelfish
Squirrelfish
Longjaw squirrelfish
Spotted goatfish
Yellow goatfish
Holocentrus rufus
H. adscensionis
Neoniphon marianus
Pseudupeneus maculatus
mulloidichthys martinicus
10
Parrotfishes
Princess parrotfish
Redband parrotfish
Redfin parrotfish
Redtail parrotfish
Stoplight parrotfish
Striped parrotfish
Scarus taeniopterus
Sparisoma aurofrenatum
Sparisoma rubripinne
Sparisoma chrysopterum
Sparisoma viride
Scarus iseri
11
Cephalopods
Caribbean reef squid
Common octopus
Sepioteuthis sepioidea
Octopus vulgaris
12
Herrings & Small Pelagics
Atlantic thread herring
Opisthonema oglinum
13
Small Herbivorous Fish
Blue tang
Doctorfish
Ocean surgeon
Acanthurus coeruleous
Acanthurus chirurgus
Acanthurus bahianus
14
Mullets & Other Detritivores
White mullet
Mugil curema
15
Gastropod Mullosks
Queen conch
Strombus gigas
16
Spiny Lobsters
Caribbean Spiny
lobster
Panulirus argus
17
18
19
20
21
22
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses &
Autotrophs
Detritus
White shrimp
Paenaeis spp.
23
24
28
Appendix II. Biomass Values for the Functional Groups and the Source of the Estimates
Group #
Group Name
1 Dolphins
2 Benthic / Reef Sharks
3 Mackerels & Tunas
4 Medium Pelagics
5
6
7
8
9
10
Marine Turtles
Large Demersal
Medium Demersal
Large Herbivorous Demersal
Small Carnivorous Demersal
Parrotfishes
11 Cephalopods
12 Herrings & Other Small Pelagics
13 Small Herbivorous Demersal
14
15
16
17
18
19
20
21
22
23
24
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses & Autotrophs
Detritus
Biomas
Source
t/km2
0.003993 E. Mohammed, 2003. Calculated from summing the biomass
of three three species T. truncatus, S. attenuata, and S.
0.096 E. Mohammed, 2003.
0.027 E. Mohammed, 2003.
0.704 Represents the combined average biomass per square
kilometer for the two species S. barracuds and C. ruber:S.
barracuda = 0.104 t/km2. Based on an estimate of 7
individuals per km2 - personal observations of S. Smikle and
Karl Aiken. Average weight of an
0.004 E. Mohammed, 2003. Final computed (EwE) figure for
1.605 AGGRA Study.
13.104 Calculated by raising the biomass available for S.
taeniopterus (= 2.184 t/km2, source AGGRA) by the 6 total
14.859 Calculated by raising the biomass available for Acanthurus
coeruleus (= 4.953 t/km2, source AGGRA) by the 3 species.
7.094 E. Mohammed, 2003.
1.422 Smikle 2007 Pedro Bank Queen Conch Survey.
0.7 Smikle, 2007. Estimated to be half that of Queen conch.
108.58 E. Mohammed, 2003.
37.336 E. Mohammed, 2003.
344.394 E. Mohammed, 2003.
3483.865 E. Mohammed, 2003.
37.892 E. Mohammed, 2003.
29
30
Appendix V. Data set for mixed trophic impact among functional groups
Group #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Group Name
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Demersal
Medium Demersal
Large Herbivorous Demersal
Small Carnivorous Demersal
Parrotfishes
Cephalopods
Herrings & Other Small Pelagics
Small Herbivorous Demersal
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses & Autotrophs
Detritus
Industrial Conch
Industrial Lobster
Multigear FRP Canoes
Artisanal Net
Dolphins
-0.0039
-0.028
0.0937
-0.1009
-0.0002
0.0132
0.04
0.0392
-0.0376
0.0548
0.095
0.2116
-0.0337
-0.018
0.0249
0.0628
0.0851
-0.0191
0.0133
-0.091
0.1519
0.0696
0.0706
0.0813
-0.0245
-0.0225
-0.0382
-0.0009
Benthic /
Mackerels &
Reef Sharks
Tunas
0.0014
-0.0323
-0.0293
-0.0042
0
-0.0525
-0.1075
-0.0042
-0.0982
-0.1646
0.0958
-0.1355
-0.0044
0.1349
0.0002
0.0561
-0.0046
0.1182
0.0959
0.0399
-0.1027
-0.0101
-0.1106
0.2201
-0.0002
-0.0201
-0.7909
-0.0253
Medium
Pelagics
-0.0295
-0.0018
-0.0448
-0.0671
0.0001
-0.0426
-0.1903
-0.0118
-0.0821
-0.0416
0.1626
0.2362
-0.0251
-0.0141
-0.0006
0.0039
0.1031
-0.0619
-0.0187
-0.1042
0.1653
0.0557
-0.0785
0.0406
0.0006
-0.0014
-0.7713
-0.0026
-0.0053
-0.0059
-0.1078
-0.187
0
-0.0496
-0.1252
0.0741
0.0355
-0.03
0.1343
0.0345
-0.0269
0.0691
-0.0002
-0.0004
-0.012
0.0297
-0.0134
-0.016
0.0152
0.0211
0.0408
0.0291
0.0002
0.0001
-0.5168
-0.0125
31
Marine
Turtles
-0.000
0.011
-0.005
0.043
-0.000
0.017
0.081
0.009
0.036
-0.378
-0.064
0.005
0.14
0.013
0.050
-0.04
0.006
0.053
0.099
0.440
-0.089
0.285
-0.157
0.155
-0.049
0.015
-0.039
-0.002
Appendix V continued. Data set for mixed trophic impact among functional groups
Large
Small
Medium
Group #
Group Name
Herbivorous Carnivorous Parrotfishes Cephalopod
Demersal
Demersal
Demersal
0.0021
0.0037
0.0007
0.0008
0.001
1
Dolphins
-0.0155
0.0006
0.0237
0.0051
-0.022
2
Benthic / Reef Sharks
0.0251
0.0906
0.0065
0.0066
0.020
3
Mackerels & Tunas
-0.3605
-0.6906
0.0549
-0.0282
-0.270
4
Medium Pelagics
-0.0001
0.0001
-0.0004
0.0001
0.000
5
Marine Turtles
-0.0498
-0.1304
-0.009
-0.0127
-0.006
6
Large Demersal
-0.1173
0.2805
-0.4335
-0.2793
-0.130
7
Medium Demersal
-0.0418
-0.0938
0.0056
-0.0141
-0.027
8
Large Herbivorous Demersal
0.0052
-0.0427
-0.1982
-0.0321
-0.177
9
Small Carnivorous Demersal
0.05
-0.107
-0.0054
-0.2505
0.014
10
Parrotfishes
-0.0724
-0.0089
-0.0949
0.0881
-0.179
11
Cephalopods
-0.0152
-0.0007
0.0016
-0.0131
-0.006
12
Herrings & Other Small Pelagics
0.038
-0.2706
-0.0273
-0.2501
0.060
13
Small Herbivorous Demersal
-0.0002
-0.0781
-0.0168
-0.0337
-0.042
14
Mullets & Other Detritivores
-0.0001
-0.001
0
-0.0008
-0.000
15
Gastropod Mullosks
-0.0401
-0.0155
-0.0104
0.0092
-0.023
16
Spiny Lobsters
0.0574
0.0281
0.1913
-0.0003
0.150
17
Benthic Crustaceans
0.0364
-0.0026
0.166
0.0028
0.179
18
Mulluscs and Worms
0.0778
0.025
-0.0442
-0.0253
-0.020
19
Echinoderms
-0.0125
-0.0178
-0.0103
0.0841
-0.010
20
Zoobenthic sessile animals
0.0215
0.0166
-0.0052
-0.0323
-0.003
21
Zooplankton
0.026
-0.0065
0.0512
0.0327
0.056
22
Phytoplankton
0.0371
0.5137
-0.0327
0.4007
0.030
23
Algae, Seagrasses & Autotrophs
0.1439
0.002
0.1843
-0.0451
0.160
24
Detritus
Industrial Conch
0.0001
0.001
0
0.0008
0.000
25
Industrial Lobster
0.0144
0.0056
0.0037
-0.0033
0.008
26
Multigear FRP Canoes
0.0165
0.5771
0.0636
0.0229
0.302
27
Artisanal Net
-0.0029
0.0133
-0.0065
0.0064
0.000
28
32
Appendix V continued. Data set for mixed trophic impact among functional groups
Small
Mullets &
Gastropod
Group #
Group Name
Herbivorous
Other
Mullosks
Demersal
Detritivores
-0.0007
0.0011
-0.0035
1
Dolphins
0.0111
-0.0529
-0.0032
2
Benthic / Reef Sharks
-0.0103
0.0337
0.0009
3
Mackerels & Tunas
0.1441
-0.1854
-0.0227
4
Medium Pelagics
-0.0002
0
-0.0042
5
Marine Turtles
-0.0057
0.0366
0.0009
6
Large Demersal
-0.1122
-0.2818
0.0383
7
Medium Demersal
0.0009
-0.0176
-0.0064
8
Large Herbivorous Demersal
0.0494
0.1041
0.0275
9
Small Carnivorous Demersal
-0.1784
-0.0572
-0.0468
10
Parrotfishes
-0.2353
0.0643
0.0481
11
Cephalopods
0.0057
0.0028
-0.0002
12
Herrings & Other Small Pelagics
-0.3277
-0.0803
-0.0856
13
Small Herbivorous Demersal
-0.0119
-0.0828
-0.0118
14
Mullets & Other Detritivores
-0.0011
-0.0004
-0.4968
15
Gastropod Mullosks
0.0131
0.0252
0.0017
16
Spiny Lobsters
-0.0503
-0.2709
-0.0517
17
Benthic Crustaceans
-0.0614
-0.023
-0.0027
18
Mulluscs and Worms
-0.007
-0.03
0.0025
19
Echinoderms
-0.0116
0.0191
-0.005
20
Zoobenthic sessile animals
0.0028
-0.0631
-0.0004
21
Zooplankton
-0.0323
0.0347
-0.0067
22
Phytoplankton
0.5097
0.1281
0.1644
23
Algae, Seagrasses & Autotrophs
-0.0845
0.2671
0.1491
24
Detritus
Industrial Conch
0.0011
0.0003
-0.4954
25
Industrial Lobster
-0.0047
-0.009
-0.0006
26
Multigear FRP Canoes
-0.0883
0.2655
0.0182
27
Artisanal Net
0.0048
-0.1597
0.0049
28
Spiny
Lobsters
-0.0074
-0.2344
0.0067
0.0482
-0.0001
-0.148
0.0255
-0.0114
-0.0414
0.0549
-0.0588
0.0579
-0.0286
-0.0339
-0.0004
-0.3497
-0.021
0.1281
0.1084
-0.0276
0.0351
0.0609
0.064
0.1203
0.0004
-0.2332
0.3074
0.0075
33
Benthic
Crustacean
-0.000
0.003
-0.007
0.043
0.000
0.002
0.062
0.004
-0.160
0.011
-0.071
0.000
-0.005
-0.007
-0.000
-0.010
-0.443
-0.206
0.002
-0.012
0.047
-0.046
0.005
0.415
0.000
0.003
-0.05
-0.026
Appendix V continued. Data set for mixed trophic impact among functional groups
Group #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Group Name
Dolphins
Benthic / Reef Sharks
Mackerels & Tunas
Medium Pelagics
Marine Turtles
Large Demersal
Medium Demersal
Large Herbivorous Demersal
Small Carnivorous Demersal
Parrotfishes
Cephalopods
Herrings & Other Small Pelagics
Small Herbivorous Demersal
Mullets & Other Detritivores
Gastropod Mullosks
Spiny Lobsters
Benthic Crustaceans
Mulluscs and Worms
Echinoderms
Zoobenthic sessile animals
Zooplankton
Phytoplankton
Algae, Seagrasses & Autotrophs
Detritus
Industrial Conch
Industrial Lobster
Multigear FRP Canoes
Artisanal Net
Echinoderms
0.0029
0.0974
-0.0078
0.0986
-0.0007
0.0913
-0.4795
0.0204
0.1897
-0.0601
0.1482
-0.0186
0.0075
-0.0064
0
-0.2895
-0.3338
-0.151
-0.0994
0.036
-0.0453
-0.0775
-0.0571
0.5359
0
0.1038
-0.0807
0.0182
Zoobenthic
sessile
animals
-0.0008
-0.0042
-0.0069
0.0297
-0.0003
0.0129
0.2745
0.0139
0.0207
-0.7246
-0.0909
0.0141
0.2416
0.0321
0.0008
-0.0107
0.0148
0.0068
0.0245
-0.1144
-0.1695
0.5449
-0.3876
0.0601
-0.0008
0.0039
-0.0266
-0.0068
Zooplankton
Algae,
Phytoplankto
Seagrasses
n
& Autotroph
0.0003
-0.0037
0.0058
-0.0303
0.0001
-0.0108
-0.1492
-0.0083
0.0548
0.3195
0.0794
-0.0099
-0.1046
-0.017
-0.0003
0.0206
-0.0102
-0.1533
-0.0106
-0.3899
-0.3307
0.2944
0.1714
-0.0914
0.0003
-0.0074
0.0435
0.0037
-0.0001
0.002
-0.0018
0.0096
0
0.0029
0.0313
0.0019
-0.0279
-0.049
-0.0235
0.0037
0.0156
0.0022
0
-0.007
0.0207
0.0502
0.0017
0.0597
-0.4196
-0.3515
-0.0266
0.0417
0
0.0025
-0.0156
-0.0015
34
-0.005
-0.000
-0.046
0.000
0.009
0.167
-0.017
-0.021
-0.151
0.101
0.001
-0.288
-0.025
-0.001
-0.01
0.04
0.035
0.013
-0.022
0.012
0.005
-0.451
0.0
0.001
0.004
0.014
0.002
Appendix V continued. Data set for mixed trophic impact among functional groups
Industrial
Industrial
Multigear
Group #
Group Name
Artisanal Net
Conch
Lobster
FRP Canoes
-0.0035
-0.0074
-0.0016
0
1
Dolphins
-0.0032
-0.2344
-0.0016
-0.0069
2
Benthic / Reef Sharks
0.0009
0.0067
0.0374
0.0004
3
Mackerels & Tunas
-0.0227
0.0482
-0.0646
0.0013
4
Medium Pelagics
-0.0042
-0.0001
0
0.0001
5
Marine Turtles
0.0009
-0.148
0.0428
0.0086
6
Large Demersal
0.0383
0.0255
0.1167
-0.0007
7
Medium Demersal
-0.0064
-0.0114
-0.0043
0.0003
8
Large Herbivorous Demersal
0.0275
-0.0414
0.0346
-0.1119
9
Small Carnivorous Demersal
-0.0468
0.0549
0.1715
-0.0014
10
Parrotfishes
0.0481
-0.0588
-0.0007
-0.0468
11
Cephalopods
-0.0002
0.0579
0.1396
0.0006
12
Herrings & Other Small Pelagics
-0.0856
-0.0286
-0.0019
-0.0195
13
Small Herbivorous Demersal
-0.0118
-0.0339
-0.0088
0.162
14
Mullets & Other Detritivores
0.5032
-0.0004
-0.0004
-0.0002
15
Gastropod Mullosks
0.0017
0.6503
-0.0038
-0.0037
16
Spiny Lobsters
-0.0517
-0.021
0.0289
0.4048
17
Benthic Crustaceans
-0.0027
0.1281
-0.0064
-0.1728
18
Mulluscs and Worms
0.0025
0.1084
0.0106
-0.0038
19
Echinoderms
-0.005
-0.0276
-0.048
-0.0067
20
Zoobenthic sessile animals
-0.0004
0.0351
0.0983
0.0269
21
Zooplankton
-0.0067
0.0609
0.0565
-0.0314
22
Phytoplankton
0.1644
0.064
0.1449
0.0277
23
Algae, Seagrasses & Autotrophs
0.1491
0.1203
0.0286
0.3885
24
Detritus
Industrial Conch
-0.4954
0.0004
0.0004
0.0002
25
Industrial Lobster
-0.0006
-0.2332
0.0013
0.0013
26
Multigear FRP Canoes
0.0182
0.3074
-0.1144
0.003
27
Artisanal Net
0.0049
0.0075
0.0002
-0.0512
28
35
36