The conditions for the jack mackerel stock continue to improve in general. The Scientific Committee discussed the outcomes of the Assessment Workshop held in May 2018, focusing on reviewing new data sources and evaluating the model assumptions, leading to a “full” assessment and concluding with a preferred assessment configuration. This new information reduced previous estimates of recruitment such that the projected stock increase was somewhat moderated. Fishing mortality rates in the past three years decreased and this, along with a modest improvement in recruitment, contributed to an estimated increase in biomass.

The Chilean jack mackerel (Trachurus murphyi, Nichols 1920) is widespread throughout the South Pacific, along the shelf and oceanic waters adjacent to Ecuador, Peru, and Chile, and across the South Pacific along the Subtropical Convergence Zone in what has been described as the “jack mackerel belt” that goes from the coast of Chile to New Zealand within a 35˚ to 50˚ S variable band across the South Pacific. 

A statistical catch-at-age model is used to evaluate the jack mackerel stocks. The JJM (“Joint Jack Mackerel Model”) is implemented in ADMB and considers different types of information, which corresponds to the available data of the jack mackerel fishery in the South Pacific area from 1970 to 2018. The operational population dynamics model is defined by the standard catch equation with various modifications such as those described by Fournier and Archibald (1982), Hilborn and Walters (1992) and Schnute and Richards (1995). This model was adopted as assessment method in 2010 after several technical meetings. 

At least five units of T. murphyi associated to distinct fisheries are identified in the Southeast Pacific: the Ecuadorian fishery, which is managed as part of a more general pelagic fishery within the Ecuadorian EEZ; the Peruvian fishery, which is managed as part of a jack mackerel, mackerel and sardine fishery directed exclusively for direct human consumption taking place almost entirely within the Peruvian EEZ; the northern and the central-southern Chilean fisheries which are managed as separate management units, with the northern fishery being mostly within Chilean EEZ and the central-southern Chilean fishery which straddles the Chilean EEZ and the adjacent high sea; and, the purely high sea fishery which is a multinational fishery being managed entirely within the context of the SPRFMO (it should be noted that Chile has given its express consent for the SPRFMO jack mackerel CMM to be also applied inside its EEZ).