Download Pest Fish Identification Guide - Department of Agriculture and

Pest fish of Queensland
identification guide
Fisheries Queensland
Department of Employment, Economic Development and Innovation
CS1054 11/11
© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011.
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Contents
About this guide
2
Pest fish and their impacts
2
What can you do?
3
Recreational fishers
3
Ornamental fish enthusiasts and backyard pond owners
3
Fish farmers
3
Rules surrounding pest fish
4
Mozambique tilapia (Oreochromis mossambicus)
5
Spotted tilapia (Tilapia mariae)
7
Carp (Cyprinus carpio)
8
Gambusia (Gambusia holbrooki)
10
Goldfish (Carassius auratus)
11
Three-spot gourami (Trichogaster trichopterus)
12
Pearl cichlid (Geophagus brasiliensis)
13
Oriental weatherloach (Misgurnus anguillicaudatus)
14
Climbing perch (Anabas testudineus)
15
Redfin (Perca fluviatilis)
15
Fish features
17
Pest fish
18
Native fish
18
Tail shapes
18
Glossary19
Is it a pest fish?
An easy way to distinguish a pest fish from a native freshwater fish is by
looking at the dorsal fin. Pest fish usually have a continuous dorsal fin, while
native freshwater fish usually have a dent or gap separating the front of the
dorsal fin from the rear.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
About this guide
This guide will help you identify pest fish that live in Queensland’s fresh waters. The
guide explains how pest fish affect natural aquatic ecosystems and outlines what you
should do if you capture a pest fish. The guide only includes pest fish that are currently
or potentially posing significant threats to the natural freshwater environments in
Queensland—it is not an exhaustive list of all pest fish found in Queensland.
The pest fish profiles contain general information about the species, their
distinguishing features and their habitat preferences. The photographs and line
drawings highlight the distinguishing features of the fish.
The process for reporting a pest fish sighting is outlined on page 3 and the contact
details for reporting are repeated at the bottom of each page.
Pest fish and their impacts
Pest fish are species that are not native to an area and have potential negative social,
economic or environmental impacts. Populations of pest fish have successfully
established in many of Queensland’s local waterways and are a major threat to the
high diversity of native freshwater fish in Queensland and New South Wales.
The presence of pest fish in natural waterways can have some serious impacts such as:
Habitat
• decreased water quality
• increased water turbidity and siltation
• increased nutrient loads.
Native fauna and flora
• introduction of diseases and parasites
• decreased biomass and diversity of rooted water plants
• reduced numbers and diversity of native aquatic fauna (through direct
competition for food or space, or predation)
• decreased numbers and diversity of aquatic insects
• altered food chains and other ecological processes
• increased dominance of waterbodies by pest fish.
Economic and recreational
•
•
•
•
2
increased pressure on recreationally significant species (e.g. through competition)
reduced environmental and conservation value of infested waterbodies
diminished recreational value of infested waterbodies
reduced value of recreational and/or commercial fisheries.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
What can you do?
Queensland Government relies on members of the public to report new pest fish
incursions. Information about pest fish sightings is vital in managing their impacts.
• If you sight or catch a pest fish in Queensland, please report it by calling
13 25 23 or by emailing [email protected]. Please include as much
information as possible including detailed information about the location
(GPS coordinates, landmarks, roads, etc.), the type of waterbody, a description
of the fish and, if possible, whether a photograph or frozen specimen of the
fish was retained. Visit www.deedi.qld.gov.au for more details.
Recreational fishers
• Don’t transfer pest fish between waterways—don’t use pest fish as bait.
• Obtain a permit to stock fish. Buy fingerlings from a registered hatchery to
minimise the chance of contamination with undesirable species.
• Don’t return pest fish to the water. If you catch a pest fish, kill it humanely and
dispose of it appropriately.
• Prevent unwanted hitchhikers—check, clean and dry your boats and gear
between waterways.
Ornamental fish enthusiasts and backyard pond owners
• Don’t dump fish—give unwanted aquarium fish to friends or a pet shop instead
of letting them go in the wild.
• Prevent accidental escapes—screen outdoor ponds to prevent overflow during
heavy rains.
• If possible, keep native fish instead of exotics—contact your local aquarium or
Fisheries Queensland on 13 25 23 for information on local native fish species.
Fish farmers
• Prevent accidental escapes—comply with aquaculture permit conditions
designed to prevent the escape of fish (e.g. screened water outlets).
• Don’t experiment with exotics—keep to the prescribed species list.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
3
Rules surrounding pest fish
Laws exist for the possession or sale of some exotic fish species that are found
in Queensland waterways. Legislation is constantly being updated. For the most
current information on prohibited fish species visit www.deedi.qld.gov.au or
call 13 25 23.
Some prohibited fish species legally require euthanasia by anyone who comes into
possession of them. The most humane method for euthanasing a prohibited fish
is by following the ethical euthanasia protocols recommended by the Australian
and New Zealand Council for the Care of Animals in Research and Teaching
(ANZCCART). The 2001 ANZCCART publication Euthanasia of animals used for
scientific purposes states that the most appropriate method involves stunning
the fish via a sharp blow to the back of the head just above the eyes. When
applied correctly, this causes brain destruction—the fish’s gill covers should stop
moving and its eyes should remain still. The dead fish should not be returned to
the waterway and instead should be either buried well away from the water or
disposed of in a rubbish bin.
4
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
Mozambique tilapia (Oreochromis mossambicus)
Other names: Mozambique mouth-brooder.
General information: Mozambique tilapia were first introduced into Australia in the
1970s as ornamental fish and are now regarded as one of the greatest threats to
Australia’s native biodiversity. Females carry juveniles and eggs in their mouths,
and these can survive for a considerable time after the adult dies. Therefore, new
incursions can occur when live or dead fish are released into a waterway.
Size: Up to 40 cm long.
Distinguishing features: These fish are generally deep-bodied with a thin profile.
They are mostly dark grey or almost black but can be silver with 2–5 dark blotches
or spots on the side. Breeding males can have red tips on their fins. Their caudal
fin is truncate with rounded corners. Juveniles have a small black spot at the
rear of the base of the dorsal fin and may have vertical banding on the body. The
fish (especially males) have a long snout and pronounced lips/jaws. They have
a single, continuous dorsal fin originating near the head and ending with an
extended point. Their dorsal fin and anal fin are almost symmetrical.
Male Mozambique tilapia
Female Mozambique tilapia
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
5
Gunther Schmida
Colourful adult male
Junvenile Mozambique tilapia
Typical habitat: They can be found in a variety of habitats including reservoirs,
lakes, ponds, rivers, creeks, drains, swamps and even tidal creeks and estuaries.
They usually live in mud-bottomed, well-vegetated areas and are often seen in
loose aggregation or small schools. They mainly inhabit slow-flowing rivers and
streams and still-water habitats. The males build clusters of circular nests or pits
in sandy or muddy substrate.
Mozambique tilapia nests
6
Eggs in the mouth of a female
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
Spotted tilapia (Tilapia mariae)
Other names: Black mangrove cichlid, spotted mangrove cichlid.
General information: Spotted tilapia were first introduced into Australia as
ornamental fish and are now regarded as one of the greatest threats to Australia’s
native biodiversity.
Size: Up to 30 cm long.
Distinguishing features: These fish are generally deep-bodied with a thin profile.
Their colour ranges from dark olive-green to light yellow and they have 8 or 9 dark
bars or blotches on the sides (more evident in younger fish). Adults can have red
margins on their fins and red blushing on their bodies. Their caudal fin is truncate
with rounded corners. Juveniles have a small black spot at the rear of the base
of the dorsal fin. Their single, continuous dorsal fin originates near the head and
ends with an extended point.
Typical habitat: They can be found in both still and flowing waters and prefer rocky
or muddy bottomed habitats in both non-tidal and estuarine waters.
Spotted tilapia
Juvenile spotted tilapia
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
7
NSW DPI
Carp (Cyprinus carpio)
Common carp
Koi carp
Mirror carp
8
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
Other names: Common carp/European carp, koi carp, mirror carp.
General information: Three varieties of carp are present in Australian waters—
common carp, koi carp and mirror carp (these are all the same species). Carp were
originally imported into Australia as game fish and have since spread throughout
many waterways, including the Murray-Darling Basin. It is illegal for carp to
be used as ornamental fish in Queensland. Carp pose a major environmental
threat, as they can rapidly outnumber native fish and greatly disturb aquatic
environments through their destructive feeding habits.
Size: Up to 120 cm long.
Typical habitat: They prefer warm, still
rivers or lakes with silt bottoms and
abundant aquatic vegetation. They are
rarely found in clear, cool, swiftly flowing
streams. They are tolerant of a wide
range of environmental conditions and
are able to survive extremely low levels
of dissolved oxygen.
Gunther Schmida
Gunther Schmida
Distinguishing features: These fish are medium-sized and have large, thick scales.
They vary in colour but are usually olive-green, bronze or silvery-grey on the back,
lightening to cream or silvery-yellow on the sides and the underside. Koi carp are
often brightly coloured with dark blotches over the back. Their caudal fin is deeply
forked. The fish have a moderately sized mouth with thick, fleshy lips and two pairs
of barbels (whiskers) at the corners (see photograph, below left). Their single dorsal
fin originates halfway down the body and has a stout, serrated spine at the front.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
9
Gambusia (Gambusia holbrooki)
Male gambusia
Female gambusia
Other names: Mosquitofish, eastern gambusia, top minnow, plague minnow.
General information: Gambusia were first introduced into Australia from North
America as a biological control for mosquitoes; however, this was unsuccessful.
Instead, they have had a detrimental effect on native fish through competition for
resources and their aggressive behaviour. They have a habit of nipping the fins of
other fish, regardless of size differences. Also, they prey on the eggs and larvae of
native fish and frogs.
Size: Up to 6 cm long.
Gunther Schmida
Distinguishing features: These fish have a stout body with large, round scales.
Females grow larger than males, have a deeper body and have a large, dark spot
near the vent. Males are slimmer and have a slender, elongated anal fin. Their
colour is usually olive-brown on the back, blue-grey on sides and white-silver
on the underside. Some fish have small dots on the caudal fin, dorsal fin and
body. Their caudal fin is truncate or rounded. Their head is flattened and mouth
upturned. Their single dorsal fin is short, originates well back on the body and has
soft rays.
Typical habitat: They are commonly
found in lakes and still or slow-flowing
streams. They are frequently around
the edges or among freshwater plants.
They generally inhabit warm, fresh and
brackish waters at low elevations.
Adult male (below) and female eastern gambusia
10
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
Goldfish (Carassius auratus)
Other names: None.
General information: Goldfish are popular aquarium fish. They are native to
eastern Asia and are now widely distributed in waterways throughout the southern
half of Australia. They are often mistaken for carp; however, unlike carp, they lack
barbels at each corner of their upper lip. Although goldfish do not seem to form
large populations, they are still considered to have a negative impact on native
freshwater fish. This is because they compete for food and habitat and have the
potential to spread fish diseases and parasites.
Size: Up to 45 cm long.
Distinguishing features: These small, plump, deep-bodied fish are moderately
compressed. They range in colour from bright yellow to black (usually depending
on their habitat) and many have a mottled appearance. Their caudal fin is forked.
They have a blunt head and a small, toothless, protrusible mouth with no barbels.
Their single dorsal fin is long-based and originates halfway down the body. They
have a single spine on the dorsal and anal fins.
Gunther Schmida
Typical habitat: They are a
subtropical, freshwater fish but prefer
cooler waters. They are commonly
found in streams, ponds and dams.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
11
Three-spot gourami (Trichogaster trichopterus)
Other names: Blue gourami.
General information: Three-spot gourami are very hardy and highly invasive fish
that can breathe air directly, allowing them to survive for long periods out of the
water if kept moist. They are a tropical-subtropical fish native to South East Asia
but have been introduced into many other areas, including north Queensland.
Size: Up to 20cm long.
Gunther Schmida
Distinguishing features: These fish have an elongated, compressed body with a
pair of pelvic fins in the form of long thin sensory filaments. They have a small,
upturned mouth and a long-based anal fin. Their colour is usually a uniform blue
with a pale olive tinge. They may also exhibit two dark spots—one at the base
of the tail and the second in the centre of the midline of the body. (The common
name suggests a third spot, which is the eye.) The fins contain small white spots.
12
Typical habitat: They are very tolerant
of poor water quality and usually live in
habitats that are heavily vegetated with
shallow, sluggish or standing water.
This includes waters such as marshes,
swamps, canals, rivers and lakes.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
Pearl cichlid (Geophagus brasiliensis)
Other names: Pearl eartheater.
General information: Pearl cichlids were introduced into Australia for ornamental
purposes. They are aggressive, attractively coloured freshwater fish native to South
America. They can potentially become a significant pest, because of their size,
hardiness and aggressive behaviour. Feral populations of this species are in several
areas near the Tweed River in New South Wales and in parts of Western Australia.
Size: Up to 30 cm long.
Distinguishing features: These fish are higher bodied and laterally compressed.
Their main body colour can range from pale light brown to greyish-green or dark
blue or purple; they are lighter on the underside. They are covered with bluewhite pearly flecks and often have a single dark spot on the side of the body.
Smaller fish are usually plain brown. Their fins are either totally red or have red or
black margins. Their caudal fin is truncate with rounded corners. The fish have a
rounded forehead and small, pointed mouth. Adult males develop a slight hump
on the head. Their single, continuous dorsal fin originates near the head and ends
with an extended point. The dorsal fin and anal fin are almost symmetrical.
Gunther Schmida
Typical habitat: They are very hardy
and will tolerate most environments,
including sea water.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
13
Oriental weatherloach (Misgurnus anguillicaudatus)
Other names: Japanese weatherloach, Chinese weatherfish, weatherfish.
General information: Oriental weatherloaches are native to Europe and Asia
but have been introduced into Australia as ornamental fish. Individuals exist in
natural waterways through the release of aquarium fish and through escapes from
ornamental ponds.
Size: Up to 25 cm long.
Distinguishing features: These fish are small, elongated and cylindrical with
small eyes. Females are more solidly built than males and have rounded pectoral
fins; males’ fins are more triangular or square-cut. Males also have a long, thick
pectoral ray. The fish are usually a mottled yellow-brown with black spots and a
pale underside. They have a prominent black spot at the base of the caudal fin,
which is rounded. Their mouth is small, down-turned and surrounded by five pairs
of barbels. Their single, short dorsal fin is further down the body. The fish are
covered in mucus, making them very slippery.
14
Gunther Schmida
Gunther Schmida
Typical habitat: These benthic fish are commonly found in slow-flowing or still
water with sand, mud or detritus substrates into which they can burrow. They can
survive in habitats ranging from degraded urban and rural streams and ponds to
relatively pristine headwater streams.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
Climbing perch (Anabas testudineus)
Other names: Climbing gourami, walking fish.
General information: Climbing perch are native to Asia, where they are commercially
fished as an important food source. They have an accessory air-breathing organ,
which allows them to survive out of the water for several days in moist conditions. This
gives them the ability to travel across land on their pectoral fins. They have a highly
developed predatory nature and, in times of drought, are able to bury themselves in
the mud to survive. Although there are currently few reported cases of climbing perch
in the wild in Australia, the species’ dispersal and survival ability presents a high risk
to Queensland’s aquatic environment. North Queensland is especially at risk, as there
have been confirmed reports of climbing perch in the Torres Strait Islands.
Size: Up to 25 cm long.
Distinguishing features: These fish have elongated bodies and various strong
spines on the posterior edge of their gill covers. Females have a larger girth than
males, and males have more of a knife-edged anal fin. They are a ‘muddy’ pale
brown-orange to dark greenish-brown with occasional dark blotches over their
body. Males tend to be darker than females. Younger individuals have a dark spot
on their caudal peduncle. Their caudal fin is truncate with rounded corners. Their
single dorsal fin originates near the head and extends the length of the body. Their
dorsal and anal fins reach backwards to the beginning of the caudal fin.
Mark Allen
Damien Burrows
Typical habitat: They are a tropical fish that inhabit fresh and brackish waters
throughout the world. They are most often found in canals, lakes, ponds and
swamps. They can tolerate extremely unfavourable water conditions such as low
oxygen and extreme temperatures.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
15
Redfin (Perca fluviatilis)
Other names: Redfin perch, English perch.
General information: Redfin are native to Europe and were introduced into Australia
in the 1860s for angling; these fish were popular for their fighting qualities and taste
in the United Kingdom. Although there are currently no reports of redfin in the wild in
Queensland, they are a significant pest in New South Wales and there is a high risk of
them being spread into Queensland. They are voracious predators of other fish and
invertebrates and can destroy recreational fisheries in enclosed waters by building
up large numbers of stunted fish and eliminating other species. Redfin can devastate
native fish populations by carrying the viral disease epizootic haematopoietic
necrosis (EHN). A number of native species, including silver perch, Murray cod,
mountain galaxias and particularly Macquarie perch, are highly susceptible to EHN.
Size: Up to 60 cm long.
Gunther Schmida
Distinguishing features: These deep-bodied fish have a slightly forked caudal fin.
Their body colour fades from olive-green on the back to greenish or silvery on the
sides and whitish on the belly. They have bright reddish-orange pelvic, caudal
and anal fins. Also, they have a pattern of five or more broad black vertical bands
across the back, tapering on the sides (more prominent in younger fish). Unlike
most introduced freshwater species, they have two distinctly separate dorsal fins,
the first with 12–17 strong spines and a distinct black blotch at the rear.
16
Typical habitat: They live in a variety of
habitats, but prefer still or slow-flowing
waters such as lakes, dams, billabongs,
swamps and slower moving streams
and rivers. They prefer areas with good
shelter such as snags (submerged
deadwood and trees), vegetation or
rocks, but have also been caught in
open water.
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
Fish features
The main features used to identify a fish species are shown in the following
diagrams:
head
dorsal fin
h
lengt
caudal peduncle
length
caudal fin
body depth
lateral line
pectoral fin
operculum
anus
anal fin
pelvic fin
total length
bar
stripes
blotches
saddle
blotch
maxillary
streak
dots
band
spots
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
17
Tail shapes
The different tail shapes of fish are shown in the following diagrams:
rounded
convex
emarginate
concave
truncate
truncate with
rounded corners
lunate
forked
Pest fish versus native fish
An easy way to distinguish a pest fish from a native freshwater fish is by looking
at the dorsal fin. Pest fish usually have a continuous dorsal fin, while native
freshwater fish usually have a dent or gap separating the front of the dorsal fin
from the rear.
Pest fish
Barramundi
NSW DPI
Mozambique tilapia
Native fish
Carp
18
Australian bass
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
Glossary
barbela slender, tentacle-like sensory structure on the head;
a ‘whisker’
basethe part of a projection (e.g. a fin) connected to the body
blotchan enlarged area or patch that is different in colour from
adjacent areas
brackish
slightly salty; a mixture of sea water and fresh water
caudal
pertaining to the tail or posterior part of the body
common name the informal name for an animal
dorsal relating to the upper part or surface
lateral relating to the sides
margin the edge or rim
mottled having the appearance of uneven spots or blotches of
different shades or colours
new incursion the reporting or sighting of a pest fish species in an area
where it has not previously been recorded
pectoral relating to the chest or thorax
peduncle the part of the body posterior to the anus and to which the
caudal fin attaches
posterior behind or at the back of
ray a stiff, bony spine in the fin of a fish
scientific name the formal organism name consisting of the genus and
the species
snout the part of the head in front of the eyes
spine a sharp, protruding point; also, the backbone or vertebral
column
symmetrical showing symmetry; having similarity in size, shape and
relative position about a midline
Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au
19
Report a pest fish!
Call 13 25 23
email [email protected] or
visit www.deedi.qld.gov.au