U.S. Tuna Canners Pledge More Protection for Dolphins

As a marine mammal scientist who has urged modifying tuna fishing methods to avoid killing dolphins, I welcome the announcement by major tuna canners to buy only tuna not “caught on dolphin.” Actually, at least seven different species of dolphins have been impacted by our tuna fishery. More than 5 million dolphins were killed up until 1972, after tuna boats began “fishing on dolphin” in the late 1950s.

The method of fishing for tuna on dolphins deserves further explanation. Contrary to the implication in your article and the statements attributed to American Tunaboat Assn. President August Felando, the dolphins do not follow the tuna, and they are not caught accidentally. Until about the mid-1950s, the traditional method of catching tuna was to chum the water with small fish then catch the tuna manually with poles, hooks and lines. When it was noted that tuna schools commonly swim closely beneath dolphin schools, the purse seine method was adopted. In this method, schools of a few tens to several thousands of dolphins are purposely caught in giant bag-like nets in the assumption that tuna will be caught with them.

In recent years, the U.S. government has required tuna fishermen to back down the nets, lowering special dolphin escape panels, and even to manually escort the dolphins out of the net. The government has set quotas of “acceptable” levels of dolphin deaths caused by this method. It is important to note that even now, with regulation, the dolphins are still caught purposely in the hopes of getting the tuna. The general method has not changed.

I was less than convinced by Felando’s argument that the canner’s decision will cause American boats to move to foreign ports where there is no regulation. If the U.S. consumes one-half of the world’s canned tuna and the canners hold to their pledge, then the tuna fishermen will have to change their methods, whether they dock in San Diego or in another country. The problem now will be for the tuna canners to verify that the tuna they buy were not caught by killing dolphins. Only a very small percentage of the tuna consumed in the U.S. (or the world) is now caught with hook and line. Albacore (white meat tuna) are generally caught this way, but yellow fin and skipjack tuna (light meat tuna) are now virtually exclusively caught by purse seiners.

Other far-reaching questions remain. Not the least of which is the long-term viability of the modern tuna industry. Overfishing to the decline of a species and the crash of an industry is a commonly repeated pattern in the U.S. and elsewhere.

LAWRENCE G. BARNES, Ph.D.

Natural History Museum

of Los Angeles County