Fish and trophic webs
- Created by: hanRose
- Created on: 01-01-22 17:28
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- predator- prey selectivity
- mouth size/ structure affect prey capacity coefficient
- behaviour (foraging tactics): fish select prey size to minimise different energy expenditure of capture/handling time (larger prey more costly
- Fish and trophic webs (L7)
- trophic guilds
- groups of fish - similar diet and feeding methods + similar niches/ resources
- strong evidence - resource partitioning in diverse tropical communities than in temperate streams
- concept - change in food/ flexibility in food. preference over seasons life stage: reflect complex food webs
- identify functional routes
- web analysis + classify fish communities
- categories
- piscivore
- benthic invert feeders i
- surface/ water column
- generalised invert
- plankivore
- herbivore/ detritivore
- omnivore
- parasite
- marine subsidy pathway of anadromous salmonids
- pacific salmon spewing stocks huge/ semelparous = carcasses/ deposited eggs
- important vector of nutrients (C/N/P) from sea to terrestrial/ aquatic in nutrient poor North pacific river
- ^13C/^12C / ^^15N/ ^14N ratio (heavier isotopes are marine origins) used to trace pathways of marine derived nutrient (MDN) in freshwater/ terrestrial ecosystem
- >60% invert N est from salmon- coastal Alaskan bear 94% C/N from salmon: carcasses up to 5km from river
- current/ historical salmon biomass
- biomass: historical : 156,000-254,298 current: 11,843 -13,747
- nitrogen historical: 4,853 - 6,854 current: 360 - 418
- phosphate historical 574 - 810 current 43 - 9
- loss salmon stocks (may fix naturally low nutrient status systems in low productive state - unless artificially restored
- European Atlantic salmon sea trout - similar P/N subsidy effect = but much smaller scale
- trophic guilds
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