INTRODUCTION
TO FISHERIES SECTION
Watery habitats are sometimes
managed for the benefit of fish and the people who want to catch
fish, the anglers. Such places are known as fisheries.
There are different kinds of
fisheries. For example, running water fisheries are where fish live
in streams and rivers. Still water fisheries are where fish live
in lakes or ponds.
The impact of habitat management
for fishery purposes can be very good for conservation because the
improved environment is good for other plants and animals as well.
Fish need variety in the streams they live in. At different stages
in their lives different things will be important to their survival
(B09d). Fish are an
important part of a food web (B06d).
Their presence and survival is linked to the survival of other creatures.
For example, think about what fish eat (B09a)
and which animals hunt and eat (or predate on) fish (B09b,
B09c).
Sometimes fish are put into the
water of a stream, river, lake or pond to increase the number of
fish present for anglers. Adding fish in this way is called ‘stocking’.
Many still water fisheries are not stocked. In a pond or lake, where
the water is not connected to a river or stream, fish are unable
to move freely when a good habitat is available.
In streams and rivers, however,
if the condition of the water and habitat is right for fish to breed
and live there, stocking should not be necessary.
Here are some river/stream features
which are important for fish and good for conservation in general:
1) Boulders
and fallen tree, large branches, and tree roots.
Salmon and trout like to hide from predators and can make use of
these features to do this. Cover is also important for other wildlife
like otters, crayfish and some invertebrates.
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Stable debris which
forms good in-stream cover |
2) Clean gravel
riffles – gravel that is not covered in sediment and soil,
but is loose. Salmon, trout, grayling, barbel, chub, dace and lampreys
all need clean gravel to lay ther eggs in (spawn).
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Clean gravel -
how a healthy stream bottom should look |
3) Variations
in water depth
This provides good habitat for some of the invertebrates which fish
eat.
4) Water Plants
Water plants like Crowfoot and other weed beds are very important
for fish to shelter in and for spawning. They are also a home and
food source for invertebrates and birds.
|
Healthy river with
water plants |
5)
Reeds along the edge of a river or stream bank.
Reeds can help reduce riverbank erosion and offer cover for fish
and nesting places and material for birds.
6) Bank
Cliffs – high river banks
These can provide valuable nesting sites for birds, like the kingfisher
and sand martin (B09b).
7) Shingle/gravel
bars/islands in the stream or river.
On rivers and streams which are quite wide these features are good
for providing habitats for nesting birds and cover for otters.
8)
Bankside trees and scrub
Scrubby buffer zones (L06f)
provide good cover for otters and good bird habitats. Areas of light
and shade along the riverbank provides varied habitats.
9) Wetland
areas like flooded ditches and backwaters
These provide sheltered areas for coarse fish fry production. Wet
grasslands and other wetland areas provide good habitats for birds,
amphibians, and dragonflies. Wetland areas hold water and let is
out slowly keeping the river flowing all summer.
|
Wetland at the
headwaters of a river |
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