Fishermen commonly go after the biggest fish they can find, but research indicates this approach might not be the best for sustaining fisheries. One type of big fish – fertile females – is particularly valuable for fishery health, scientists say.
More, they add, should be done to protect these big, old, fat, fertile female fish, or BOFFFFs, which is how scientists at the University of Hawaii, California State University and the National Oceanic and Atmospheric Administration identify them in a study published in the International Council for the Exploration of the Sea’s Journal of Marine Science.
The researchers brought together hundreds of investigations pointing in one clear direction, says Mark Hixon, professor of marine biology at the University of Hawaii and lead author of the study. “BOFFFFs are valuable for fish population replenishment and stability,” he said.
These big, fertile fish are key to fishery vitality for a few reasons. Because of their size advantage over smaller fish, BOFFFFs can produce many more eggs. This, by itself, is a pretty good reason to throw a few big fish back.
But there’s more: Not only can they produce more eggs, it appears that BOFFFFs also make higher-quality eggs than their smaller counterparts. These eggs, study authors say, are more likely to hatch young fish that grow and survive better. BOFFFFs also have a tendency to lay their eggs in more places, which helps increase the odds that young fish will find suitable environments to grow up in.
“Increasingly, fisheries managers are realizing that saving some big old fish is essential to ensure that fished populations are stable and sustainable,” said Hixon.
As an example, he points to the Atlantic’s cod fishery, which has been particularly affected by the loss of big, fertile female fish. In 2010, managers implemented control measures, including catch limits, to help the cod fishery there recover.
This drop in BOFFFFs was likely caused by fishermen targeting bigger fish, the study notes, because doing so impacts the size and age structure of fish populations. Authors write, “Age truncation is now known to destabilize fished populations, increasing their susceptibility to collapse.”
But after a fishery declines, is there a magic pill to solve the problem? What’s the quickest way a fishery can make a comeback after losing all its BOFFFFs? “Only if fishing is cut way back, which has obvious economic consequences,” said Hixon.