EESC 1158 Lecture Notes - Estuary, Escapement
11 Mar 2014
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Fish born in facilities, released into rivers or estuaries as fry, parr, or fish spend their whole life in aquaculture facilities (similar to livestock) Wild caught salmon (cid:0) could have been born in a river or a hatchery (cid:0) pacific salmon = wild caught (cid:0) atlantic salmon = farmed. Hatchery fish: fish protected until released (in river or estuary, little time spent in rivers, no selection for home stream, high mortality rate after release, bigger for same age, used to fighting for food, can be cannibalistic, many eggs and fry from few parents (cid:224) less diverse, less able to adapt to environmental stages, can introduce diseases to wild fish, for which there is no treatment, expensive. Wild fish: most die before parr stage, natural selection for conditions specific to home stream, cant compete with hatchery fish for food, many parents (cid:224) diverse genetics.
