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2012 A Record Catch Year For Pacific Tuna Seiners Western Central Pacific Ocean, March 20, 13

Although no hard data has been made available yet regarding the precise catches within the Western Central Pacific (WCP) Ocean, there are some strong indications that 2012 has been a record year for the purse seiner fleets operating in this area. At the same time, 2012 was also the year with the highest prices in history for skipjack tuna. Last year levels reached a record high of USD 2350 CFR Bangkok for frozen of 1.8 kg and up.

As tuna numbers in the other world’s oceans decline, more and bigger seiners are now intensifying their effort within the Western Central part of the Pacific Ocean.

In a meeting earlier this month, in Noumea, at the Heads of Fisheries Agencies, it was said that 2012 is shaping up as a year of record purse seiner catches. According to scientists, the 2012 catch could have been as high as 1.6 million M/T of tuna, which would be a record level.

Very reliable data collected by satellite as part of the VMS (Vessel Monitoring System) and numbers obtained from observers and captains’ log-sheet data, shows a drop in the trip length of the boats. This ultimately correlates quite well to the Catch Per Unit of Effort (CPUE). When the average amount of days of a trip of a purse seiner shortens, then that usually indicates that there has been a higher CPUE. In other words, within a shorter amount of time, the boat fills up faster.

In fisheries and conservation biology, the CPUE is an indirect measure of the abundance of a target species. Changes in the CPUE are inferred to signify changes to the target species’ true abundance. A decreasing CPUE indicates overexploitation, while an unchanging CPUE indicates sustainable harvesting. In the case of the WCP purse seiner catch, the unit of effort, is the catch per one purse seiner within one full day.

What the Western Pacific catch data now suggests is that CPUE per purse seiner within 2012 has strongly recovered from the sharp dip in 2011. The below graph 1, with CPUE, shows that within 2012 seiner catches started to reach again more typical levels of 30-35 M/T per day, compared to the deep low of 15 M/T around mid 2011. This was also the period that prices in Bangkok started to head for USD 2050 per M/T for whole round skipjack.


The drop in CPUE in 2011 caused the total volume caught by all purse seiners to fall in spite of the fact that the effort (total amount of days being fished by seiners) was increasing to a record level in that year (see graph 2 here below). 2011 is shown to be a year with a lot of boats in the water searching many days for fish, but with little result. The la Nina situation within the WCP during that period is seen as the main cause for this.


Purse seiner effort in 2012 seems to have been staying close to the 2011 level, and so with a CPUE climbing to a 15 M/T low to a 35 M/T high, it looks like the final 2012 catch will be significantly higher than other good years such as 2009 or 2010, the former being the last record high catch.

Based on all these numbers scientists’ analysis suggests a catch of around 1.6 million M/T for the WCP purse seiner fishery, which for 80% consists out of skipjack.

According to Dr. John Hampton, Manager of the Oceanic Fisheries Program at the Secretariat of the Pacific Community, even skipjack tuna, the species with the most robust numbers, needs close scrutiny.

“It may well be that as we start to fish these species a bit intensively, particularly skipjack tuna, that we will see a bit more year-to-year variability in the performance,” he told Radio Australia’s Pacific Beat.

“That’s probably a good sign that indeed we are reaching the sort of sensible limits of what we should be taking out of these stocks.”

Dr. Hampton says a limit of around 1.5 million tons per year for skipjack would be appropriate.

He says this would allow the population to maintain a level of around half of its ‘pristine’ levels of abundance - the level the population would maintain if there was no fishing.

“[This] should enable the stock to certainly be viable going forward but also provide profitable levels of fishing activity as well,” he said.

He also says there are concerns around levels of yellowfin tuna.

“We do think there are certainly signs in this key core area of the fishery that we need to introduce restraints on the harvest of yellowfin,” he said.