Age-Structured Production Model (ASPM) assessments of the Alfonsino (Beryx splendens) resource in the SIOFA area of the Southern Indian Ocean
Report
2020
Permanent link to this Item
Authors
Journal Title
Link to Journal
Journal ISSN
Volume Title
Publisher
Publisher
Faculty
License
Series
Abstract
An Age-Structured Production Model is applied to assess the Alfonsino (Beryx splendens) resource in the West and East SIOFA areas of the Southern Indian Ocean. Data limitations restrict these applications to deterministic variants, which assume no variation in annual recruitment about the predictions from a stock-recruitment relationship. The models are fitted to the CPUE series and single year of commercial catch length distribution information available. Both West and East stocks are estimated to be at about 60% of their pre-exploitation spawning stock biomass levels, and well above the levels corresponding to MSY (MSYL). These results are insensitive to all sensitivities explored, except for changes in the value assumed for natural mortality (M). For the Base case assumption of M=0.2, projections under constant annual catches up to 40% above the 2018 levels remain above MSYL for the next two decades. However, if a less productive situation is assumed (M=0.15), there are some cases of spawning biomass dropping below MSYL within 10 years for both areas, including even for continuation of the 2018 catch for the East area.
Description
Reference:
Brandão, A., Butterworth, D. & Johnston, S. 2020. Age-Structured Production Model (ASPM) assessments of the Alfonsino (Beryx splendens) resource in the SIOFA area of the Southern Indian Ocean. ,Faculty of Science ,Department of Mathematics and Applied Mathematics. http://hdl.handle.net/11427/33103 .