Stock Status of Pacific Bluefin

The International Scientific Committee for Tuna and Tuna-like Species in the North Pacific (ISC) last assessed the stock status of Pacific northern bluefin tuna in 2004. The exact population level is unknown due to lack of data, but the ISC was able to make qualitative assessments of abundance.

Population size, known as biomass, fluctuated widely over the 50 years of catch data examined in the assessment (1952-2002, see Figure 1 below). The population experienced record lows in the late 1980s and has since rebounded to an intermediate level. There was a particularly successful spawning event in 1994, and fish from that year class have greatly supplemented the population. The population of spawning fish has generally declined since 1995, however. Scientists fear that the current high fishing rates will not be sustainable over the long term and will result in further declines of the population. The high catch of small fish is of particular concern.

NOAA Fisheries does not classify Pacific bluefin as overfished and does not consider overfishing to be occurring.

Figure 1. The Pacific-wide catch data on which the 2004 ISC assessment was based.