Sonic tagging for mixed fisheries

ANCHORAGE, EGAN CIVIC CENTER—Sonic tagging may help address a fisheries management problem in Upper Cook Inlet: the incidental catch of king salmon by setnetters and drift fleet fisherman who are actually after sockeye salmon off the shores of the Kenai and Kasilof Rivers.

The findings are in a study presented to the Alaska Board of Fisheries by Dr. David Welch of Nanaimo, Canada. What’s that mean for the Matanuska-Susitna Basin waters more than 50 miles upstream? It could provide a pass-through corridor for northernbound sockeye and coho, while still allowing the commercial fleet and setnetters to fish. This effort would focus Upper Cook Inlet commercial fishermen on Kenai stocks and leave the Mat-Su-bound fish alone.

“There’s only one or two Ah-ha moments in a career. And for me this is one of them,” said Mac Minard, a fisheries consultant at the Board of Fisheries for the Mat-Su Borough. “This changes everything and could be as significant as sonar was to escapement estimation years ago,” said Minard, who was a fisheries biologist for 27 years with the Alaska Dept. of Fish & Game.

Welch laid a series of listening arrays on the bottom of Upper Cook Inlet. King salmon with sound-emitting tags passed over the arrays, giving off their signals. With this, Welch was able to see where the kings move and gather and when they move, patterns that not much is known about.

Minard calls the findings enlightening. Watch him in video:

“He demonstrated that King Salmon off shore of Kenai and Kasilof rivers have a tendency to migrate back and forth and be vulnerable for an extended period of time therefore  increasing their probability of capture in that set net fishery.

• He also demonstrated that sockeye salmon were off shore of that and vulnerable to capture in the drift fleet. The third thing he demonstrated with crystal clarity was that those sockeye and those kings are separated vertically in the water column, and consequently a mechanism to maintain a directed commercial fishery on sockeye and afford the required and requisite protections for king salmon exist by simply adjusting the depth of the net.

And it’s something that people have thought about for awhile. It’s something that most fishermen would have recognized but now we have empirical evidence of the highest quality that tells us that this exists. So it opens the door for maintenance of a viable commercial fishery directed at sockeye, and still allows us the opportunity to afford conservation measures for primarily Kenai and Kasilof king salmon and that has benefits to the Mat-Su Borough because we’re able to take those sockey in a terminal area, continue to fish, allow the king salmon escapements into the other systems and preserve the corridor outside of those terminal areas allowing fish to migrate back up into the Mat-Su. It’s all connected,” Minard said.

Salmon returns to the Mat-Su have been plummeting. The Matanuska-Susitna Borough Fish & Wildlife Commission has made the case that the leading cause is commercial fishery interception in Upper Cook Inlet.

For more information call Mat-Su Borough Public Affairs Director Patty Sullivan at 907.355-0103 or  This email address is being protected from spambots. You need JavaScript enabled to view it.

Top photo: inside the Fish war room at the Fisheries meeting.

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