Bigger doesn't mean better for hatchery-released salmon

[Derby]

Subject: Bigger doesn't mean better for hatchery-released salmon



https://phys.org/news/2019-11-bigger-doesnt-hatchery-released-salmon.html

 

[Birdsnest]

Good news if true overall. Will greatly reduce the cost and increase output for these operations.

 

[searun]

This research follows another UBC Master's Thesis - here's link http://www.marinemammal.org/wp-content/pdfs/Allegue_2018.pdf

Essentially harbour seals were preferentially preying upon Qualicum River out-migrant coho smolts which were larger in release size than their much more abundant Chinook smolts. We have also seen some very significant survival rates on Stamp/Robertson Chinook that have been net penned to hold them in the Alberni Inlet for a few weeks to mess with the out-migrant timing which reduces predation. The net pen results were so good, that DFO went back to make sure there wasn't an error in data. Mimicking the natural diversity of nature is the way to avoid unanticipated consequences. When humans try introducing standardization turning out homogenous smolts that is a recipe for disaster once the predators figure out what is going on.

Hatcheries managed to a one size fits all model are a recipe for predators to figure out the new abundant food supply we dump into the environment every spring. Learning and applying approaches that mimic nature's diversity to our hatchery programs is the way forward. Hatcheries are not evil, they are a tool to help overcome some of the ecosystem damage and loss of natural productivity that is human caused....we can't turn back the clock, and trying to rely solely on natural wild only production and expecting a return to former levels of natural productivity is fool-hardy IMO.