It’s late autumn, so the season for bottom trawling has begun in Cobscook Bay in eastern Maine. First, fishermen pursue sea urchins and, later, scallops. I am a fan of fresh scallops, so I appreciate their efforts to catch scallops on the cold mornings in midwinter. Even though no one seems entirely happy about rules, both harvests are closely regulated in an attempt to prevent destruction of these fisheries. Let’s hope the rules work.
One does not have to travel far in Down East Maine to see what overfishing can do to coastal villages and the people who work there. First the cod disappeared, then the herring and finally the sardines. There is much finger pointing at who was responsible — Russian trawlers, fish-locating sonar technology and local greed. But, the fish are gone, fish canneries are abandoned and much of the population has left town. Even where protected, cod show only a slow recovery, suggesting permanent changes have occurred in the ecosystem.
What happened in this area of coastal Maine is similar to what is reported from fisheries worldwide. The most desirable, large predatory fish, such as swordfish and snapper, are first depleted. By some estimates their numbers in the sea are only about 10 percent of what they once were. Then fishermen focus on smaller species that were once considered trash fish. Nonselective bottom trawling is employed, reworking, degrading and denuding the deep sea floor at a rate that is roughly similar to the rate of deforestation we deplore in the Amazon Basin. Finally, sardines and menhaden are the target of the catch.
This pattern exemplifies what marine biologist Dan Pauly once called “fishing down” marine food webs, in which humans first exploit the top predators, then their prey and finally the small fish that support all the marine food web. Roughly 8 percent of the total productivity to the seas goes to support the human population globally. If we could see beneath the waters and know how things have changed, we’d deplore what we would see.
In our local community, there are fishermen in pursuit of clams, lobsters, urchins and scallops. Their work is cold, tough and demanding. Interestingly, compared to 50 years ago, no one makes a living from traditional fishing, except for those working with farm-raised salmon in large pens.
Now there is an increasing urge to harvest seaweed, known as rockweed, which lines the coast. With the fish gone, it is time to scrape the rocks clean of seaweed that once offered a nursery for the fisheries in the open waters. If we are ever to see these fisheries recover, protecting rockweed will be an important foundation for the effort. Observations also suggest that rockweed is an important nursery for the young of shellfish and lobsters.
Whether appropriate rules will be put in place to maintain adequate rockweed habitat, productivity and regeneration remains to be seen. Already, those exploiting rockweed are lining up to defend their practice. Claims that these folks are simply trying to make a living are tough to ignore, but scientific studies to support claims of a sustainable harvest are as scarce as cod fish.
William H. Schlesinger of Lubec is president emeritus of the Cary Institute of Ecosystem Studies in Millbrook, New York.