River Restoration for FISH Flashcards
What is the life cycle of fish
Alevins-fry-parr-smolts-adults-lay eggs
how long does it take alevins to become fry
3-4 weeks
how long do parr remain in fresh water
2-3 years
what life stage sees a change from freshwater to seawater
smolts
what do fry and parr require for survival
unpolluted well oxygenated water, plenty of food, refuge from very high flows
what do juveniles and adults require for survival
unpolluted well oxygenated water, plenty of food, sufficient depth and cover
what spawning conditions do fish require
unpolluted well oxygenated water, clean gravels, access to spawning grounds
what are the problems with pollution in fish survival
industrial, agricultural, acidicfication
what are the erosion problems with fish survival
trampling of banks, and bank erosion, can reduce depth and increase siltation
what are the siltation problems with fish survival
forestry agriculture, chokes stream, reduces production and thus reduces food availability
what are the barriers to migration problems with fish survival
wiers dams and debris block the paths for fish upsteam and so they cant lay eggs in the places they want to
what are the lack of water problems with fish survival
abstractions, diversions and drought induced by climate change, reduce channel depth and size, thus limiting production of food within the channel
How can we restore bank erosion
fencing and limited stock access
How can we restore widened channels
physical narrowing or marginal planting
How can we restore pollution impacts
clean up point source, manage diffuse sources, change forestry type, add buffer reedbeds to stop leaching of chemicals
How can we trap and reduced silt
agriculture management buffer zones
How can we manage bankside trees
coppicing
How can we manage flows
reduce abstraction, compensate flows, flow deflectors
How can we remove barriers
remove unessiscary barriers to fish migration, or make current barriers more manageable for fish
how high vertically can atlantic salmon clear
1.4 meters
how high vertically can brown trout clear
1 meter
since when have trent salmon seen decline
late 1800’s
how many wiers on the river trent itself alone
19
how were fish targeted on the trent
netting in tidal reaches
how many people live in the trent catchment
6.5million
what are the negatives of a fish ladder
can take up a lot of land, can be expensive, often very large
what are the advantages of baffle passes like the denil and the Alaskan A
can be used where there is little area
what is different about the larnier fish pass
textured bottom to create flow that fish can swim up
what measures can be put in place to improve eel migration upstream
eel brushes, can be other structures like pegs
what was the aim of the trent salmon restoration project
identify problems, remove habitats, stock parr, monitor stocks
how many parr were added to the trent between 1998 and 2003
780,000
what was the performance of the salmon trent project
success, salmon returned for the first time in 70 years,
how are fish seen to pass through the barriers
ID salmonid scan, or lasers, or video
