Apr 9 2017

NATIONAL FISHERMAN: When is menhaden like a mortgage?

What do forage fish and real estate have in common? Location, location, location.

A new study led by University of Washington fishery science Professor Ray Hilborn reveals some surprising relationships between predator success and prey abundance.

The paper, “When does fishing forage species affect their predators?” was published Monday in the journal Fisheries Research in response to the 2012 Lenfest Report, which set the recent standard for forage fish management by asserting that an across-the-board reduction in the commercial harvest of forage fish would result in higher numbers of fish species that prey on them.

“It looked reasonable that if you appropriate half of the production of a prey species by a fishery that you can’t support so much production of predators,” said Carl Walters, professor emeritus of the University of British Columbia’s Institute for the Oceans and Fisheries. “That seemed perfectly reasonable. It was just wrong.”

According to this study, prey species follow the real estate principle of investing in prime locations. When forage fish are abundant, the research shows, their population spreads over a wider area, creating smaller subpockets around a core reproduction zone. When they’re in low abundance, they retract to the core region. Successful predators keep their breeding grounds close to that core region, maintaining access to food even in times of low prey biomass.

Read the full story at National Fisherman


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