Chinook salmon swims out of a pollock net through excluder portals Credit:

Chinook salmon swims out of a pollock net through excluder portals

Bycatch Excluders-1

A Chinook salmon safely swims out of a pollock net through the salmon excluder “portals

February 05 2014
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After watching video taken inside a trawl net in 2002, behavioral differences between pollock and salmon gave scientist an idea. John Gauvin works  closely  with the trawl fleet and is a industry expert when it comes to bypath reduction.


“Looking at this video with Dr. Rose and John Gruver a former pollock captain who works for United Catcher Boat Association, and I; We said hey there might be a way to actually get salmon to swim out of a pollock trawl.”


Researchers saw salmon where able to swim against the flow better then the pollock.


“You would see the salmon moving forward in the net at times, and you would see the pollock steadily dropping back with some ability to move forward but at a loss. They would move a little bit forward and then move a lot back.”


After testing with many tunnel and funnel devices, researchers came up with the flapper in 2012.
The design resulted in a 25 to 37% Chinook salmon escapement, with vary little loss of pollock.


“So that one is in wide use right now in the pollock fishery and it works, but we also think it is some what of a difficult design to widely adopt into the fishery; because the way you have to weight that panel to create the escapement opportunity takes a lot of tuning.”


The second generation Excluders  can not be massed produced. Gauvin says that it has to be tailored to the horse power of the vessel and how they fish. A new and improved design is already in the works.


“We are pretty excited about this over and under device and we are going to be doing more testing on it this spring in the Gulf and then hopefully again in the fall in the Bering Sea.”


Gauvin believes reducing by catch is what will drive the direction of our fisheries.


“What is interesting to me  today is that in many ways the success in the fisheries is not so much of what you catch, but what you don’t catch. Fishermen spend a lot of time figuring out how to not catch the things there are not suppose to so they can continue to make a living.”

Learn more about salmon excluders at

Fish Radio is also brought to you by Ocean Beauty Seafoods, celebrating 101 years of partnership with Alaska’s coastal communities.  In Kodiak, I’m Stephanie Mangini