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SEAFOOD.COM NEWS by John Sackton – July 20, 2012 — The International Seafood Sustainability Foundation (ISSF) has updated its review of tuna stocks, and has made two major changes.
First Bigeye tuna’s overall rating was changed from yellow to orange, meaning the conservation status of this stock has worsened. The reason according to ISSF, is that nations that are members of the regional fisheries management organizations failed to act on scientific recommendations to either lengthen the current fishing closure, or to establish individual bigeye vessel limits.
An orange rating means the fishing mortality is above MSY, and there are no management measures in place that would reduce the fishing effort. As per its charter, if this condition persists over time, ISSF members would have to stop purchasing Bigeye in fisheries where it is massively overfished.
The second change was in the status of yellowfin, where the biomass rating was changed from orange to green. The spawning biomass of yellowfin has now grown to be above MSY levels, meaning the stock is in balance with the current level of fishing pressure in a long term sustainable manner.
The ISSF also released a rating of fishing methods, cautioning that pole and line fishing, which is a method that has been embraced uncritically by British retailers following the film ‘The End of the Line’, is actually a more problematic fishing method than some purse seining.
The reasons given are that the pole and line fisheries rely on huge supplies of live bait fish to attract and keep tuna near the boats; and that these bait fish are often taken from vulnerable and unregulated stocks. The amount of baitfish available in the WCPO is a limiting factor to the amount of pole and line fishing that can occur. In addition, the bait species captured are generally more fragile than temperate baitfish species.
ISSF also rates purse seining on FAD’s as yellow, along with Pole and Line fishing.
The two purse seine methods that are green are setting on free schools, and setting on tuna / dolphin associations.
Finally, the ISSF notes some figures regarding global tuna catch, which has plateaued.
The global catch of albacore, bigeye, bluefin, skipjack and yellowfin in 2010 was 4.34 million tonnes, a 4% decrease from 2009. Catches increased steadily until the early 2000s and have stabilized since then. This plateau is explained by continuously-increasing catches of skipjack, offset by declining catches of yellowfin and bigeye. Ranked by species (using the 2006-2010 average = 4,471,000 tonnes), the majority of the catch is skipjack (55%), followed by yellowfin (27%), bigeye (9%), albacore (8%) and bluefin (1%). In terms of fishing gear, 63% of the catch is made by purse seining, followed by longline (14%), miscellaneous gears (gillnets, handline, traps, etc., 13%), and pole-and-line (10%).