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This report describes the results of concurrent fixed and random-site blue cod (Parapercis colias) potting surveys carried out off north Otago in January 2018. Estimates are provided for population abundance, size and age structure, sex ratio, total mortality (Z), and spawner biomass-per-recruit ratio. This is the fourth survey in the north Otago fixed-site survey time series, following those in 2005, 2009 and 2013; and the second random-site survey, with the first survey in 2013.

We used 3 years of electric-fishing catch data from 3 Canterbury Rivers to explore capture-efficiency of shortfin and longfin eels. If stop nets were not used during multi-pass electric-fishing surveys, eel abundance was underestimated by 3–40%. Capture-efficiency increased strongly with increasing eel size. Elvers will be underestimated relative to large eels in electric-fishing surveys that do not use stop-nets and only conduct a single pass.

The fisheries taking RCO 2 and 3 1989–90 to 2016–17 are described based on commercial CPUE data. Long-term standardised CPUE analyses, based on daily catch records, were conducted on RCO 2 and 3. These analyses served as a platform to predict the final complete year CPUE from the first 3 to 7 months of data. This predicted CPUE is used to drive in-season catch recommendations for RCO 2 and 3, which can result in a recommendation for increased annual catch if it exceeds the respective TACCs.

Age compositions of orange roughy (Hoplostethus atlanticus) were estimated for Puysegur Bank (ORH 3B) from samples collected from a 1992 trawl survey and a 2015 acoustic survey. The age compositions were produced for use in assessments of this stock.