types
of freshwater fish
The following are some of the
most common fish to be found in the rivers, streams and lakes of
Cornwall:
Salmon
• Salmon are territorial (G1)
and they do not like other fish in their area of water. They
hover in steady currents, slightly off the bottom.
• When spawning they nest in gravel, mainly in the upper
headwaters of a river. Salmon fry are up to 1.5 cm long and
the young salmon can be identified by its pointed nose and
'V' shaped tail. (See
the Salmonid Life Cycle F02)
• Fry grow up to parr (young adult) stage, where they
are about 10 cm long. They stay in river for 2-5 years before
turning into smolts and going off to sea. When fully grown
they come back to spawn in the same river in which they were
hatched.
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72lb salmon |
Trout
and Sea Trout
• Trout are one of the most
valuable species to be found in fisheries. They have a big
mouth, some look more like a pike. Some have a torpedo shape.
• Adult trout need a good depth of water and bank
cover - they like to hide.
• Trout generally
stay in the river, though some (mainly females) have a sea-going
stage and come back as Sea Trout. They go to sea for a year
and come back larger than those that stay in the river.
• Rainbow trout are non-native game fish farmed
for food and sport |
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Brown
trout |
Grayling
• Live in swims and pools mid-river downwards - size
30-50cms. In Cornwall they are found in the Inny and Otter.
• They may have daily migration of 3-4 km from overnight
position to daytime feeding stations. |
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Grayling |
Bullheads
• Bullheads have a thin body and an enormous head - size
10-20 cm.
• A bullhead is territorial and will spend its entire
life on one stretch of river. Not good swimmers, they live under
stones in slack water of shallow water or riffles.
• Feed on invertebrates
• Spawn in late
April/May, eggs are left as yellowy/orange sticky mass on a
stone |
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Bullhead |
Roach
• Roach are of the carp family and measure about 10-20
cm.
• Found in still waters in Cornwall. |
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Roach |
Rudd
• Rudd are similar to roach - size 20-30 cm
• They
live in lakes in Cornwall. |
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Rudd |
Perch
• Found in lakes in Cornwall - size 25cm and over
•
Predate on roach and rudd. |
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Eels
• All eels head to the Sargasso Sea to spawn
then spread all over northern Europe
• Eels have
gills like other fish. Eels also have pectoral fins and the
long dorsal fin is continuous with a ventral fin - size 60-70
cm
• Elvers (young eels) will swim up tiny flows
of streams and ditches
• Adults will wriggle
across fields to get to nearest river or pond
Brook
lampreys
• Similar to an eel, but has
a round mouth and holes or gills along the side of its head
• Found in the upper reaches of rivers - size 12
-16 cm |
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Eel |
Carp
• Carp are a major fish species in Cornwall and thrive
in ponds
• It is a large family and includes the Common or King
Carp, Mirror carp, Koi carp and goldfish
• The wild carp is popular with anglers, very long a thin
and a fast swimmer |
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Carp |
Stone loach
• Many rivers in Cornwall will have stone loach but only
in small numbers
• Prefer rivers to still water and have less trouble with
polluted water
• Feed on midge larva
• Their yellowy eggs are stuck to gravel and guarded by
the male fish |
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Stone Loach |
Minnow
• Very small fish, about 9 cm long. Colour ranges from
silver and grey to brown and yellow
• Minnows can be an important part of trout diet. They
live in upper reaches of rivers
• They survive well because they do not need gravel for
spawning. The eggs are shallow laid and hatch quickly - unlike
salmonids |
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Minnow |
Stickleback
• Small (5-8 cms) and silvery with spines on its back
• Found in ponds, rivers and ditches. It builds a nest
from plants. |
Other species
Other wild fish live in our rivers as well as many introduced
species. |
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Bream |
Dace |
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