Marine Policy Project Part 2

Overfishing of the Atlantic Bluefin Tuna

The Atlantic bluefin tuna is the largest species of tuna and lives near the top of the food chain within its ecosystem. Powerful and strong, they are known to have large appetites and a varied diet which allows them to grow to an average size to about 6.5 feet long and weigh up to 550 pounds, though some specimens have been known to be much larger. These fish are highly migratory, with distribution ranging from Newfoundland and Iceland to the Atlantic coasts of Brazil and Africa. Bluefins can be most commonly found in subtropical areas of the North Atlantic Ocean, the Mediterranean, and Black Seas. The fish typically grow slowly and are relatively late to mature. There are two known spawning areas of these tuna; the Gulf of Mexico and the Mediterranean. This knowledge and improved fishing techniques have brought in higher quantity catches over the years. However, the conservation and management of the tuna hasn’t changed quickly enough along with these techniques to address the depletion of stock in the Atlantic. Over the past 40 years, the International Commission for the Conservation of Atlantic Tunas (ICCAT) reported a decline of 72% in the population of eastern Atlantic and Mediterranean stock and an 82% decline in the western Atlantic stock (NOAA(a) 2009). The bluefin population has been continuously declining for several years and despite some measures being taken to manage the population in the Atlantic, it still remains highly hunted and highly coveted due to the high demand and increasing scarcity of this fish. The species is prized by both wealthy sushi consumers due to its rich, fatty flesh and by fishermen who can sell a single catch for tens or hundreds of thousands of dollars. Currently, this combination has brought the species to the brink of extinction, with environmentalists claiming the species has no chance to recover if existing fishing practices are allowed to continue.

Countries that fish the eastern Atlantic bluefin, particularly in the Mediterranean region, have done so at two to three times the sustainable level (NOAA(a) 2009). ICCAT has the task of managing the population of bluefin in this area. One of their policies has been to significantly lower catch quotas in recent years in an attempt to allow fisheries to recover. In its assessment of stock levels, ICCAT assumes no illegal fishing and bases perceived stocks on reported catches only. However, because of illegal and unreported fishing, the actual catch far surpasses these quotas. Declines in the bluefin population may actually be much greater than reports would indicate. According to one study, it is estimated that the quotas were exceeded by 62% between 2005 and 2011 and 77% between 2008 and 2011 (Pew(b) 2012). Because of ICCAT’s early assumption that the eastern and western bluefins were two separate populations, eastern quotas were much looser than the strict quotas in the west (Moran 2008).

The stock of western Atlantic bluefin, which is only known to spawn in the Gulf of Mexico, is fished primarily off the North American coast. Populations in this region are also severely depleted to just over a third of what it was in 1970 (Jorge 2013). ICCAT has implemented and enforced stricter catch limits in this region and, unlike in the Mediterranean, seems to be working as the population has recently stabilized (Wildlife 2009). Unfortunately, the Gulf population faces another problem in the form of the BP oil spill in 2010. This occurred during the peak spawning season in an area where mature bluefin are known to reproduce, thus possibly affecting the survival rate of eggs and larvae (Pew(a) 2010). Because of the long maturity time for the bluefin, the full effects of the oil spill on bluefin stocks are not yet known.

The issue of the declining bluefin population is not simply the dismissal of catch limits, but also the ways in which fish are caught. One of the most wasteful fishing techniques is the use of surface longlines. These lines reach up to 40 miles in length with baited hooks attached along the lines. The lines are deployed in spawning areas where hundreds of bluefin are caught along with other non-target species (Pew(a) 2010) every year. Conservationist groups have encouraged the National Marine Fisheries Service to ban the use of longlines in the Gulf during spawning season to give stocks time to recover (Moran 2008). In addition to longlines, purse seining is another wasteful, yet commonly used, fishing technique. This involves the release of a vertical net that is circled around a target school of fish. The line is drawn in from the bottom of the net, catching everything inside. In the case of the bluefin, this means that dolphins will often be caught alongside (FAO 2001).

Some new strategies have been suggested to address the declining populations of bluefin. One of which is the use of aquaculture, or aquafarming. This technique involves the cultivation of bluefin under controlled conditions. Ideally, this would relieve some pressure on the wild stocks of tuna and allow them time to recover. The issue that has come up with aquaculture is that some of these farms have been using wild juvenile bluefin which takes them out of the wild before they can reach maturity and reproduce, thus hurting the wild stocks even further. Additionally, a large farm of bluefin requires a larger amount of food, thus putting the prey species at risk as well. These farms can also contribute a significant amount of waste and pollute the surrounding water and sea floor. Another attempt at rescuing the bluefin was a 2010 proposal by Monaco to the United Nations to ban international trade of the fish. With most of the demand for bluefin coming from Japan, this would greatly reduce demand from the Atlantic stocks, thus allowing them to fully replenish. The ban was rejected, with several delegates fearing the negative effect this would have on their respective countries economies (Jolly 2010). In another strategy, in 2011 an environmental group petitioned the National Oceanic and Atmospheric Administration to declare the bluefin as an endangered species. Despite continuously declining stocks, the NOAA announced that the Atlantic bluefin did not warrant the endangered species title because it believed stricter fishing laws recently imposed adequately supported recovery efforts (NOAA(b) 2011).

In order to successfully correct the problem that overfishing has caused for the bluefin population, new steps must be taken to properly manage, conserve, and preserve this fish. Policy-wise, this could include the closing of fisheries during spawning season or perhaps a multiyear ban to let the populations grow back to sustainable levels. This would require ICCAT or a single body to regulate and enforce these tactics and would require the cooperation of all countries. The quotas also need to be strictly enforced, with penalties applied to those to go over quota or are found guilty of illegal/unreported catches. Should that not work, or perhaps in addition to new policy, aquaculture must be improved to a point where it does not have a negative impact on the surrounding environment nor require wild juvenile stocks of bluefin to operate. Ultimately, the best solution is in the hands of the consumer. If consumer demand can be lowered, the tuna will not be as aggressively sought after. While this may be the best solution, it may also be the most difficult.

As a top level predator, the Atlantic bluefin is essential at maintaining balance within the ecosystem. With such a large distribution of these fish throughout the Atlantic, it is safe to say that they play a large role in the overall health and balance of the ocean. The extinction of this species would certainly have serious environmental consequences but unfortunately, it is hard to predict what exactly those would be.

Bibliography

FAO (Food and Agriculture Organization of the United Nations). 2001. Fishing Gear Types. Purse Seines. Technology Fact Sheets. In: FAO Fisheries and Aquaculture Department [online]. Rome. Available from http://www.fao.org/fishery/geartype/249/en

Jolly, D.; Broder, J. (2010, March 18). U.N. Rejects Export Ban on Atlantic Bluefin Tuna. New York Times. Retrieved from http://www.nytimes.com/2010/03/19/science/earth/19species.html?src=sch&pagewanted=all&_r=0

Jorge, M., 2013. Battle for the Western Atlantic Bluefin Tuna. National Geographic. Available from http://newswatch.nationalgeographic.com/2013/01/10/battle-for-the-western-atlantic-bluefin-tuna/

Moran, J.M., (2008). Ocean Studies Introduction to Oceanography (2nd ed.). Boston, MA: American Meteorological Society. p. 384

NOAA(a) (National Oceanic and Atmospheric Administration), 2009. Statement from Dr. Jane Lubchenco, Under Secretary of Commerce for Oceans and Atmosphere and NOAA Administrator, Announcing Support for Listing Atlantic Bluefin Tuna on International Trade Endangered Species List. Available from http://www.noaanews.noaa.gov/stories2009/20091014_bluefintuna.html

NOAA(b) (National Oceanic and Atmospheric Administration), 2011. NOAA sets fishing quotas for bluefin tuna. Available from http://www.noaanews.noaa.gov/stories2011/20110630_bluefintuna.html

Pew(a) (Pew Charitable Trusts), 2010. BP Oil Spill Threatens Bluefin Tuna Spawning Ground in Gulf Of Mexico. Available from http://www.pewenvironment.org/news-room/fact-sheets/bp-oil-spill-threatens-bluefin-tuna-spawning-ground-in-gulf-of-mexico-8589940931

Pew(b) (Pew Charitable Trusts), 2012. Illegal Bluefin: Challenges to Counting Eastern Atlantic Bluefin Tuna. Available from http://www.pewenvironment.org/news-room/fact-sheets/illegal-bluefin-challenges-to-counting-eastern-atlantic-bluefin-tuna-85899420681

Wildlife Extra. 2009. Endangered Atlantic bluefin tuna formally recommended for international trade ban. Available from http://www.wildlifeextra.com/go/news/bluefin-tuna938.html#cr