[font face=Serif][font size=5]Recreational fishing brings salt marsh die-off[/font]

June 11, 2012 | Contact: David Orenstein | 401-863-1862

[font size=4]As recreational fishing activity has reduced predators in many of Cape Cod’s salt marsh ecosystems, Sesarma crabs have feasted on grasses, causing dramatic die-offs of the marshes, according to a new study. The researchers assessed the “trophic cascade” in several experiments that also ruled out alternative explanations for the problem.[/font]

[font size=3]PROVIDENCE, R.I. (Brown University) — Recreational fishing is a major contributor to the rapid decline of important salt marshes along Cape Cod because it strips top predators such as striped bass, blue crabs, and smooth dogfish out of the ecosystem, according to new research by Brown University ecologists.

With far fewer predators in areas where recreational fishing is prevalent, native Sesarma crabs have had relatively free rein to eat salt marsh grasses, causing the ecosystem to collapse, said Mark Bertness, chair of Brown’s Department of Ecology and Evolutionary Biology and the paper’s senior author. He led a series of experiments and measurements published online in the journal Ecology that he said unavoidably implicate recreational fishing in marsh die-off.

“We had to be so careful about dotting all the ‘i’s and crossing all the ‘t’s and making sure that we had ruled out all alternative hypotheses, because even within the scientific community, there are plenty of fishermen who don’t want this to be true,” Bertness said. “Certainly out in the general public there are plenty of people who are into recreational fishing who don’t want it to be the problem.”

Bertness said salt marshes are vitally important because they protect coastlines from erosion, filter pollutants headed from land to sea, and act as nurseries for the young of many species of crabs and fish. Studies that assign economic value to varying ecosystems rank salt marshes at or near the top, he said.

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