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Pacific Skipjack Catches Hit 5-Year Low Global, September 12, 12

Strength isn’t always in numbers, or in ever improving fish finding technology.
There were a record number of purse seiners scouring the Western and Central Pacific Ocean last year, but the increased effort did little to prevent skipjack tuna catches from reaching a five-year low.

In 2011, a grand total of 283 vessels caught 1.330,667 MT of skipjack – the lowest in the past five years and nearly 200,000 MT lower than the record catch in 2009, according to the latest report from the Western and Central Pacific Fisheries Commission (WCPFC).

At the same time, fleets have gradually been expanding since 2006, after remaining relatively stable in number for more than a decade. The four main distant water fishing nations – Japan, Korea, Taiwan and the U.S. – account for the majority of the fleet, with a combined total of 136 vessels in 2011.

The “clear drop” in purse seine skipjack catches, paired with the highest total fishing effort, indicates lower catch rates, suggests the report which was discussed in August at the WCPFC’s annual scientific committee meeting.

The poor fishing largely took place in the second half of 2011 when skipjack catch rates “fell quite strongly” during the region’s three-month fishing ban on fish-aggregating devices (FADs), says John Hampton, Oceanic Fisheries Program manager at the Secretariat of the Pacific Community (SPC).

“I believe the fleet was having trouble finding free schools of either species [skipjack and yellowfin] in any quantity in the area that they were working,” says Hampton. The FAD closure, in effect from July through to September, was first implemented in 2009 to restrict the catch of juvenile bigeye tuna, which are caught incidentally with FADs.

The low catches were also “unusual,” says Hampton, because “starting in October, the catch rates didn’t really bounce back like they had in previous years after the FAD closure.”

Cooler water temperatures from the climate pattern, La Niña, may also have been a factor. The Western and Central Pacific Ocean was in a prolonged La Niña state in 2008, 2010 and the majority of 2011, and the weather conditions tend to drive tuna to the western regions of the equatorial zone. With the increased catches in the waters of Papua New Guinea, Federated States of Micronesia, and Solomon Islands during those years, the skipjack stock may have been responding to the high catches, says Hampton.

La Niña conditions are also believed to negatively impact the “recruitment” or next generation of young fish in the tuna population. “There may have been reduced recruitment coming into the fishery in the early part of 2010, and that’s then flowed through to depressed catch rates in the purse seine fishery,” he says.

Skipjack catches seem to have recovered in the early part of 2012, says Hampton.