Stunning salmon broodstock with 95+% egg survival

01 August 2020

Challenge

The Southern Southeast Regional Aquaculture Association (SSRAA) is a non-profit corporation working to enhance and rehabilitate salmon production in southern Southeast Alaska.

They have been stunning salmon broodstock with electricity for 25 years but their existing batch stunning process had certain inherent inefficiencies they wanted to improve.

Challenge #1: create a constant flow of stunned fish. The “fits and starts” of their existing batch process made it difficult for their small team to run an efficient operation.

Challenge #2: avoid removing ripe females from the water. Maximising egg production with a high survival rate is their top priority but egg loss caused by removing fish from the water was an unavoidable consequence of their stationary “shock box”.

Solution

We designed a flow-through electric stunner, the A-HSU®, that paired with their rotary lift fish screw to provide a regular flow of fish from the water to the sorting table.

The stun settings were precisely calibrated to ensure every fish is fully stunned before exiting the stunner. This allows for gentle handling of the ripe female fish; maximising the quality of egg production.

Results

SSRAA’s Production Manager, Bill Gass said, “We achieved our production goals in 2018, with survival to eye consistently at 95% or above and a chum salmon egg-take of 70,000,000. We plan to expand to 120,000,000 eggs in future and will be retrofitting our older hatchery with an identical Ace Aquatec stunner next year.” 

Bill shared their electric stunning results at the 2019 Alaska Fish Culture Conference and we’re now working with his team to plan their next electric stunner installation.

You can see their stunning results yourself in the video below: