Catch advice of jack mackerel in the Southern Pacific Ocean

The advised catch is based on the recent stocks assessment that reflects the low numbers of recruitment. The fisheries committee will meet at the start of 2014 to agree on a quota which will be partly based on the advised catch. This committee consists of international representatives from the ministries of the participating countries. To formulate the advice to the fishery committee, fisheries biologists met this year for the first Science Committee (previously Science Working Group) meeting of the South Pacific Regional Fisheries Management Organisation (SPRFMO) in La Jolla, California USA.

Jack mackerel in the Pacific Ocean

Jack mackerel (Trachurus murphyi) has a large distribution area in the Pacific Ocean – from the Chilean and Peruvian coast up to New Zealand. As a large part of the distribution area is outside of the 200 mile zone (known as the Exclusive Economic Zone) of adjacent countries, international fishing also takes place.

Decline in jack mackerel population

At the end of the seventies jack mackerel was fished in this area by Russia and Poland, among other countries. In this period a fishery also developed in Chile and fishing for jack mackerel increased. The total catch peaked in 1995 with approximately 5 million tonnes. Because of the lack of strong year classes and increasing catches, the stock declined from more than 20 million tonnes at the end of the eighties to 10 million tonnes around 2000.

This period was followed by a number of years in which recruitment was well below average, while catch levels remained about the same. This resulted in a further decline of the stocks to its lowest point in 2011 with 3.8 million tonnes (2.0 million tonnes of spawning biomass).

Catch quotas via SPRFMO

Although management measures were applied in the territorial waters of Peru and Chile, there were still no catch quotas for fishing outside the 200 mile zone. The introduction of the SPRFMO meant that catch quotas could also be introduced in international waters. However, with the announcement of the instruction of the SPRFMO, a number of new jack mackerel fisheries developed, including an European jack mackerel fishery. In addition to the lack of strong year classes, this development has also contributed to the decline in the jack mackerel stock.

Recovery plan for jack mackerel in the Pacific Ocean

It took the SPRFMO a few years to put measures in place that enable management of the Southern Pacific Ocean. From 2013 the convention entered into force on the conservation and management of high seas fisheries in the South Pacific Ocean. A recovery plan for jack mackerel will be required to bring the stock within biologically safe limits within the foreseeable future. These biological limits have yet to be defined exactly. Preliminary calculations show that they may be around 5.5 million tonnes (measured in spawning biomass). The recovery of jack mackerel will also depend on recruitment strength. Environmental variables such as water temperature also play a role here and cannot be managed by fisheries management.

Science Committee increases efforts

In addition to activities relating to jack mackerel, the Science Committee is also working on measures to limit the bycatch of sea birds and sea mammals, the management of bottom fishing for orange roughy and the protection of Vulnerable Marine Ecosystems (VMEs).

Niels Hintzen from IMARES Wageningen UR has been taking part in the Science Committee (previously Science Working Group) meetings since 2009.