Global Fish Population Barely Treading Water


Managing fish stocks represents a unique challenge: It combines the difficulties posed by sustainable agriculture and wildlife conservation in a single knotty problem. Harvesting and protection compete for priority, and the loser is usually conservation, evidenced by the fact that a quarter of the world's fish stocks are presently over-exploited. Given the crisis state of the world's oceans and fisheries, it is imperative that we create a network of marine reserves to bolster ailing fish stocks and shore up the livelihoods of struggling fishermen.

Although regulatory mechanisms, such as the Magnuson-Stevens Act, have combated collapse in some species, populations are still alarmingly depleted. Recent reports of fish recovery are tainted by shifting baseline syndrome, where managers measure populations against recent levels instead of historic levels. History provides accounts of the abundance of cod when settlers first arrived in New England and how lobsters were so plentiful in the 1700s they were fed to prisoners (the convicts eventually got so fed up with lobster that they revolted). There may be more fish now than there were in 1990, but present-day populations are still abysmal when compared to those of 1790.

The difficulty, then, is moving in the direction of historic levels while accepting the reality that fishing must continue. Marine reserves help solve this problem.

A marine reserve is an area in which no fishing can occur. Reserves differ from Marine Protected Areas (MPA), which afford some security, but are also open to extraction in many cases. While 34 percent of American waters have MPA status, less than 1 percent are marine reserves. As a result, fishing is occurring in many nominal parks, the maritime equivalent of shooting bison in Yellowstone.

When properly administrated, reserves dramatically enhance fish populations and marine ecosystems. In a meta-study conducted in 2003, biologist Benjamin Halpern found that “on average, creating a reserve appears to double density, nearly triple biomass, and raises organism size and diversity by 20-30 percent relative to the values for unprotected areas.” Not only are overfished species helped, but other species also experience indirect positive effects.

Still, fishermen generally oppose reserves on the grounds that no-extraction zones steal valuable fishing territory. However, their opposition is ironic because marine reserves can actually improve fishermen's catches: Abundant fish populations within the reserve tend to migrate into the surrounding waters, where they can be caught. Marine reserves confer other economic benefits as well. For example, New Zealand's Poor Knights Island reserve has provided substantial revenue via scuba diving tourism.

Biologists agree that 40 percent of the world's oceans must be off-limits to fishing to ensure stock recovery; no mean feat considering that scarcely more than 1 percent is presently protected. Although the U.S. has no shortage of reserves and MPAs, most of them span inadequate territory. For example, California's much-heralded Channel Islands Marine Sanctuary only protects 241 square nautical miles. The effectiveness of a marine reserve, not surprisingly, increases with its size; reserves the size of the Channel Islands may produce local benefits, but they fail to help the ocean at large. 

Creating marine reserves is a certain policy prescription for a pressing issue, and President Barack Obama ought to manage it; after all, even President George W. Bush designated 140,000 square miles for protection in Hawaii. If Obama wants to positively affect marine conservation and rehabilitate his own ailing environmental image, he can start by founding new reserves in the Gulf of Mexico, whose sea life was hammered by overfishing long before the Deepwater Horizon went up in flames. A large Gulf reserve would regenerate the region's decimated fish stocks and, in the longer run, solidify the now-tenuous livelihoods of the Gulf's fishermen and shrimpers. No marine habitat or group of fishermen is more in need of the cure that a reserve would provide.

Photo Credit: Wikimedia Commons