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 ...view middle of the document...
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....