Download FAR 2024/46 Stock assessment research for Chatham Rise orange roughy in 2023

Dunn, M.R. (2024). Stock assessment research for Chatham Rise orange roughy in 2023. New Zealand Fisheries Assessment Report 2024/46. 36 p.

The orange roughy stock assessment research conducted in 2023 is described.

A description of the fishery, including the spatial distribution, and commercial fishery catch rates, was completed for two ORH 3B stocks, the Northwest Chatham Rise, and the East & South Chatham Rise.\

Updated stock assessments were not completed. The reasons for this were problems caused by inconsistent orange roughy age data, the productivity of the stock (reproduction) being lower than expected, undue reliance on certain data sets in determining the results (especially orange roughy age and length data), problems in interpreting the biomass survey data used to inform the model about stock trends, and problems with technical population model specifications, including how model parameters were estimated.

Possible solutions to the problems are discussed, including the possible benefits of spatially resolved population models, or alternatively the use of greatly simplified population models.
Future research is suggested to help resolve the problems encountered in 2023.