JULY 2020
NICE & RICH
23
Uku Fishery in Hawaii: Healthy and Sustainable by the Western Pacific Regional Fishery Management Council (WPRFMC) ■ The fishery for uku (Aprion virescens) is sustainable and very healthy, according to the new stock assessment released by the NOAA Pacific Islands Fisheries Science Center (PIFSC) at the June 2020 meeting of the Western Pacific Regional Fishery Management Council’s Scientific and Statistical Committee (SSC). The lead assessment author, Dr. Marc Nadon, said that the 2018 spawning stock was estimated to be 1.8 million pounds, which is two and three-fourths times the calculated sustainable threshold of 663,705 lbs. This means that in 2018, the fishery harvested uku at 57 percent of the sustainable harvest rate. The fishery is so healthy that in the time span of 70 years (1948 to 2018) there have only been two years that the fishery was at risk of overfishing, which happened in 1988 and 1989, coinciding with years when fishermen attested that there were “choke” big-sized uku in the ocean. The assessment concluded that the uku stock in the main Hawaiian Islands is not overfished (population size not too low) and not experiencing overfishing (sustainable harvest rate). This new assessment used a sophisticated catch-at-age statistical model (the first of its kind for the Western Pacific region) that fits to available data, or uses the model that predicts values as close as possible to the observed data. This assessment is considered “data-rich” as it combines data from the commercial sector (catch, size composition and catch rates), noncommercial sector (catch) and independent diver surveys (abundance). PIFSC’s efforts to work with fishermen to understand the data and fisheries are commendable and contributed to the production of this important scientific tool. This assessment passed the Western Pacific Stock Assessment Review, a rigorous independent peer-review, in February 2020 and the review of the Council’s SSC. The finding that another fishery in Hawai‘i is sustainable attests to the sustainability consciousness of local fishermen. The uku fishery has operated for more than 70 years, taking advantage of the seasonal spawning in Penguin Banks and the evolution of the fishery from a summertime to year-round fishery. During that time, the fish population remained sustainable due to fishermen using their traditional ecological knowledge. Uku is a popular fish in the bottomfish fishery, second to the Deep Seven bottom fish. There is a large noncommercial component to this fishery, which uses a diverse set of fishing methods.
This Kobe plot shows the stock status of uku in the main Hawaiian Islands, with the amount of fishing on the vertical axis and the amount of fish on the horizontal axis. The points in the green box indicate that the stock is not overfished (population size not too low) and not experiencing overfishing (sustainable harvest rate) since 1989.
The fishery supplies a good white-meat fish to the market and is processed as fresh fish fillets and steaks. The Council will be using this new scientific information to set the annual catch limit for the uku fishery. . . . WPRFMC