Big trouble

A new report on fisheries found that world seafood stocks are declining so rapidly that a collapse could occur by 2050.

WASHINGTON - Clambakes, crabcakes, swordfish steaks and even humble fish sticks could be little more than a fond memory in a few decades. If current trends of overfishing and pollution continue, the populations of just about all seafood face collapse by 2048, a team of ecologists and economists warns in a report in Friday's issue of the journal Science.

"Whether we looked at tide pools or studies over the entire world's ocean, we saw the same picture emerging. In losing species we lose the productivity and stability of entire ecosystems," said the lead author Boris Worm of Dalhousie University in Halifax, Nova Scotia.

"I was shocked and disturbed by how consistent these trends are — beyond anything we suspected," Worm said.

This is something that watermen on the Chesapeake Bay have seen with regard to menhaden and sport fish, as well as oysters, crabs, and sea grass. Menhaden are small filter-feeding fish that run in huge schools. While inedible to us, they are a primary food source for many sport fish and sea birds. In the Chesapeake Bay, they support our beloved striped bass (we call them rockfish). As pollution and overfishing has dramatically reduced the schools of menhaden in the Bay, the number of rockfish has also declined. Some recent studies have concluded that the entire Bay menhaden population could be wiped out by overfishing in the next five years.

Another relationship that supports the study’s findings exists between sea grasses in the Bay and their effect on oyster and crab populations. The Bay was once famous for the abundance of shellfish it produced. But bad fishery management and pollution, mostly fertilizer and farm runoff, have conspired to severely restrict the Bay’s yield. When nitrogen rich water feeds into the estuary, it sparks the growth of huge algae blooms. The blooms, in turn, suck all of the oxygen out of large swathes of the Chesapeake, producing “dead zones”. Without enough oxygen in the water, sea grasses, home to many a Blue crab, and oysters (they can’t just swim away) perish. Oysters, like menhaden, are critical to the Bay’s health because they help filter out bacteria and other particles that cloud or pollute water. Dirtier water means less sunlight can reach the seafloor and that, in turn, means fewer areas can grow sea grasses. As populations dwindle, they become more susceptible to disease and the cycle begins to feed on itself.

If the recent history of the Chesapeake Bay is a microcosm for the world’s fisheries, we are going to be in serious trouble.