Population collapses hit these smaller fish hardest

Species like sardines, anchovies and flounder may grow quickly and reproduce at a rapid rate, but that doesn’t make them any less likely to experience dramatic drops in population.

In fact, a new study finds that these fast-developing fish may be more vulnerable to population devastation than their larger, slower swimming counterparts like sharks and tuna.

Malin Pinsky, assistant professor of ecology and evolution in the School of Environmental and Biological Sciences for Rutgers, has studied and observed the changes in population weathered by 154 fish species over the past 60 years, and discovered that life on land is quite different from life at sea.

"Rabbits are doing pretty well compared to rhinos," said Pinsky. "Mice thrive while lions, tigers and elephants are endangered,” he added. It seems a very different story for marine species (where the smaller fish struggle more than the larger fish), according to Pinksy, who believes overfishing might play a large role in this land-sea discrepancy.

"Overfishing is a problem throughout the world and across all species, including slow-growing fish like sharks, many of which are in serious trouble," said Pinsky. "But it turns out that fishery collapses are three times more likely in the opposite kinds of species - those that grow quickly."

Overfishing paired with climate variations can serve to further increase the chance for population collapse in smaller fish, according to Pinsky and his report on the matter – published recently in the journal Proceedings of the Royal Society B: ""If environmental factors are driving the population down, previously sustainable levels of fishing might suddenly drive a collapse. The proper response would be to quickly change fishing practices, but every political or bureaucratic process has some lag," he said.

Pinsky collected data from fisheries management agencies worldwide to compose his report, and collaborated with David Byler, who works in operations research and financial engineering at Princeton University, to hone mathematical analyses. Going forward, Pinsky hopes to focus on summer flounder, a species that is currently experiencing population drops off the coast of Mid-Atlantic U.S. states due to warmer waters.

Funding for the research was provided by the National Science Foundation.


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