Per-recruit stock assessment of wahoo (Acanthocybium solandri) in the southwest Pacific Ocean


Zischke, Mitchell T., and Shane P. Griffiths
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A stock assessment incorporating sensitivity in biological parameters and potential fishery management strategies for wahoo (Acanthocybium solandri) in the southwest Pacific Ocean was undertaken to assess the stock status of this species for 2008–2010. Selectivity probabilities at age were similar for 2 commercial longline fisheries and a recreational sport fishery. However, the median exploited length and age were slightly higher in the commercial fisheries than in the recreational fishery. Current fishing mortality (Fcurrent) was predicted to be lower than limit and target reference points, with the exception that Fcurrent exceeded the target reference point FSSB40 (fishing mortality at which the spawning stock biomass per recruit [SSB/R] is 40% of the SSB/R at F=0). This result indicates that wahoo may be at a greater risk of recruitment overfishing than of growth overfishing. Of the fishery management scenarios tested, introduction of a slot limit in the recreational fishery had the greatest effect on assessment results; however, this effect was relatively minor and may not be practical to implement. Given the relatively short life span of wahoo, ongoing biological monitoring and rigorous collection of catch and effort data may facilitate continued assessment of this species in the southwest Pacific Ocean.