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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.

Fly fisherman
Fly fisherman

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).

Releasing fry
Releasing fry

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.

A fishing pond
A fishing pond

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.

Stable debris which forms good in-stream cover
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).

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
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).

High bank cliffs
High bank cliffs

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.

Gravel bars in river
Gravel bars in river

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.

A river view
A river view

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
Wetland at the headwaters of a river

Fisheries Section Contents:

Salmonid Life Cycle (F02)

Types of Freshwater Fish (F03)

Angling (F04)

Ponds & Lakes (F05)

Pond Design (F06)

Creating a Wildlife Pond (F07)

Fish Life Cycle - Exercise (F08)


Fishy Bits - Exercise (F09)

  produced by the WESTCOUNTRY RIVERS TRUST as part of the CORNWALL RIVERS PROJECT  
 

www.wrt.org.uk
www.cornwallriversproject.org.uk