Sustainable seafood
Fishing methods make a difference
Some fish are in more trouble than others, with two determining factors — the method of fishing, and the biology of the fish. Once-common fish such Chilean sea bass, grouper, orange roughy, Pacific rockfish/snapper, and shark are considered over fished and threatened around the world today. The Chilean sea bass, for instance, can live as long as 50 years and reproduces at 10, but it's often caught before it's old enough to reproduce.
Bottom trawling
Pacific rockfish, a name for more than 70 species along the West coast, don't mature until they're 20 and are over-fished from bottom trawling, a highly effective fishing method but one that damages seafloor habitat. In Alaska and British Columbia, however, rockfish are generally caught using hook-and-line or bottom longline methods that have little impact on the seafloor. In addition to using low-impact fishing methods, populations of rockfish in Alaska and British Columbia are stable and well managed.
Dredging
Wild clams and scallops are dredged, a method that also destroys the sea bottom environment. Like trawling, dredging is very wasteful of "bycatch," meaning other marine life that's caught but not wanted. Some clams and scallops are farmed on rope lines in a sustainable manner now and some continue to be hand-harvested from tidal zones. But most clams and scallops on restaurant menus are likely to be dredged unless the method of harvest is identified.
Shrimp and prawn typically are the best-selling seafood items, accounting for nearly a third of all seafood sales across the United States. Avoiding most shrimp, however, is one of the first steps consumers can take for sustainable seafood.
Trap-caught
Trap-caught wild shrimp is environmentally friendly. But most wild shrimp is caught by trawlers and shrimp trawlers have among the world's highest level of bycatch. The U.S. National Marine Fisheries Service says that in the Gulf of Mexico, an astonishing three pounds of bycatch are caught for every pound of shrimp that goes to market.
There are some environmentally friendly shrimp farms, but most shrimp farming operations destroy coastal habitats and harm local fisheries, putting local fisherman out of work. On the other hand, nearly all trout and catfish sold commercially now are raised on freshwater farms and earn a "green" rating on sustainability for reasons related to being fresh-water fish. (Learn more about farmed fish.)
Latest technologies
As wild fish stocks dwindle around the world, giant fishing companies are using the latest technologies, including military technologies, to delve deeper into the world's oceans. These technologies include sonar-mapping systems that enable fishermen to penetrate deep into regions that once were considered too difficult to fish. Boats also are using heat and depth sensors, as well as satellite images that show water temperatures where certain fish are most vulnerable for trawling.
As the shallow-water fisheries everywhere have collapsed, there has been a worldwide scramble to exploit the resources of the deep ocean, with devastating consequences," says ocean ecologist Dr. Callum Roberts, of the University of York. "Forty percent of the world's trawling grounds are now waters deeper than the edge of the continental shelves. Some new technology is so efficient that these deep-sea trawlers are not just harvesting fish, they are literally mining them."
In the deep sea, the species and habitats are much less able to bounce back from the effects of fishing than those that live in the shallow seas. "The pace of life in the deep sea is literally glacial," explains Roberts. "Species grow extremely slowly and they live to extraordinary ages, so, for example, the orange roughy can reach 150 years old and they don't reproduce until they are in their mid-20s to mid-30s."