Under the Microscope
December 7, 2007
_In Danger of Extinction: Fishing May Kill Off Vaquita Porpoise_
p. According to a Nov. 16 Nature News article, the most critically endangered species of porpoise may go extinct in two years.
p. The vaquita, the smallest species of porpoise, is found only in the northern part of the Gulf of California. Scientists estimated in 1999 that the total population numbered 600. The results of a recent Conservation Biology survey estimate that only 150 have survived.
p. The greatest threat to the species is fishing. Fishermen kill approximately 40 vaquita per year as bycatch in nets. Scientists believe that once the vaquita population falls below 100, the species will no longer be able to sustain itself because of the lack of genetic diversity. Genetic diversity is the degree of variation of genetic traits among individuals of a population. Without genetic diversity, the population as a whole is less able to cope with environmental change and disease. In a population with low genetic diversity a single disease could wipe out the majority of the species. Genetically diverse populations have greater chances of survival.
p. The World Wildlife Fund, Nature Conservancy and Conservation International have made a joint $10 million pledge to buy fishermen’s boats and pay them not to fish.
p. Although this solves some immediate problems, long-term solutions are also necessary. The fishing industry in the region cannot be stopped entirely, but fishing regulation enforcement can be improved. Areas where nets are legal need to be more stringently regulated. In addition, money should be invested in developing safer nets. Nets can be designed with acoustic deterrents. These deterrents should be tested for safety and effect. If these deterrents are successful, they should be made compulsory for all legal nets in the region.
p. The vaquita is the second species of porpoise to be pushed toward extinction in the past decade. The same human activities harmful to the vaquita, like fishing and pollution, were also detrimental to the Yangtzee River dolphin, the baiji. The baiji was declared functionally extinct in December of last year after an expedition intending to transfer the surviving members of the species to a cleaner waterway failed to find a single suitable one.
p. The fight to save the vaquita is a part of a larger struggle to maintain biodiversity. Biodiversity, the variation of species on Earth, is important to the health of the Earth just as genetic diversity is important to the health of populations. The more diverse the species of Earth are, the more the Earth is able to adjust to shifting climates and conditions.
p. The major problem with preserving biodiversity is that the benefits to the environment in general are barely affected by the loss of a single species; the overall health of the world did not change much with the loss of the baiji. Unfortunately, the most important people to convince, the fishermen, have the most to lose financially. It is hard to convince fishermen to quit their jobs to save an obscure porpoise. It is therefore the responsibility of the governments of the world to provide subsidies and incentive-based fishing management, which will maintain biodiversity.
p. The costs of these preservation programs for single species may seem high, but each species lost is a loss for biodiversity. A common analogy made is that every species on Earth is like a rivet in the hull of a ship. Every species lost is another rivet wrenched out. A few rivets can be lost to no effect — in fact, many can be. But eventually one too many will be plucked out, and the ship will sink.