Applications of habitat data to fishery management Distribution and abundance of habitat for...
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Transcript of Applications of habitat data to fishery management Distribution and abundance of habitat for...
Applications of habitat data to fishery management
Distribution and abundance of habitat for different life stages• Barriers to migration; Waterfalls / dams• Adult habitat; Deep pools / cover • Spawning habitat; Glides / smaller substrates• Fry habitat; Shallow / smaller substrates• Parr habitat; Deeper / larger substrates
Assessing habitat quality & condition• Cover for fish; in-stream and bank structure• Climate control; shading • Pressures; impacts of Land and water use
In-stream coverShelter & territories; physical cover from floods & predators
• Size of substrates – Roughness layer• Interstitial spaces – subsurface layer• Flow type• Vegetation• Large woody debris
Typical habitat requirementsLife Stage Salmon Brown Trout
Spawning Eggs Alevins
3+ m channel widthGlide or riffle flow (35-80 cm/s ¹)ˉWater depth 17-76 cmSubstrate Golf–tennis ball (20-100mm)Low fines (< 1 mm) 2.3 – 8 %Depth of substrate >15 – 25 cm
< 3 m channel width Glide or riffle flow (15-75 cm/s ¹)ˉPea-tennis ball substrate sizeLow fines (< 1 mm) 8 – 12 %Depth of substrate >14 cm
Fry (< 1 yr)< 20 cm depth
Golf – tennis ball substrate size Shallow / broken water / Fast flow
Golf ball – tennis ball substrateShallow /medium flow / marginal cover
Parr (=> 1 yr)20 – 40 cm depth
Tennis – football substrateDeeper / broken water / fast flow
Variety of substrateDeeper / slower waterUndercut banks / tree roots
Smolt Habitat connectivity Habitat connectivity
Adult Deep pools > 80 cm depth Deep water > 0.4 m depthSlow sustained flow Bank / bed / canopy cover
Typical salmon habitat – low gradient
Adult pool habitat
Spawning habitat
Fry habitat
Mixed juvenile habitat (0 – 1++)
Typical salmon habitat – moderate gradient
Adult pool habitat
Spawning habitat
Fry habitat
Mixed parr habitat (1 – 2+)
SFCC walkover Field surveys– Main components
General observations• Channel dimensions; Area of habitat• Channel type; gradient / character• In-stream cover; Flow & substrate types / LWD• Bank cover; bank type / riparian vegetation / shade
Point location observations• O.S Grid refs; Survey start / end points• Spawning; Area / type / condition• Adult pools; Area / depth / cover• Obstacles; type / height / fish passage• Modifications; revetment / embankment / pollution