Download FAR 2025/50 Characterisation and CPUE for jack mackerels in JMA 3

The fishery for jack mackerels in JMA 3, which includes the southern part of New Zealand’s EEZ, was
characterised using data from 1989 to 2024.
There was little target fishing for jack mackerels in JMA 3 until the 1990s when the area was at the
forefront of the “invasion” of Chilean jack mackerel into New Zealand waters. A target fishery
subsequently developed, mainly using midwater trawling. Catches declined during the 2000s, but have
been stable since 2010.
Because of low observer coverage, a statistical model was developed to estimate the catches of the
Chilean jack mackerel and the native greenback jack mackerel in the JMA 3 fisheries (the other native
species, yellowtail jack mackerel, is largely absent in JMA 3). Catches estimated using this model
demonstrated that the Chilean jack mackerel comprised the majority of the JMA 3 catch until the 2020s.
The species modelling also allowed the development of standardised catch-per-unit-effort series that
were intended to provide an indication of trends in abundance, with a focus on the status of the native
greenback jack mackerel. However, data on the size and age composition of the catch suggested that
greenback jack mackerel in JMA 3 is not an independent stock, but comprises larger and older fish that
likely originated in another area.
As a working hypothesis, greenback jack mackerel in JMA 3 were linked to the stock in JMA 7, and
CPUE from that area was used to conclude that the stocks in both areas were Likely to be at or above
the target.
Chilean jack mackerel are not considered to be a self-sustaining stock in New Zealand waters, but there
are some indications of ongoing arrivals from wider Pacific stock, at a lower level than in the 1990s. In
particular, most jack mackerels caught around the Chatham Islands are Chilean jack mackerels.