CPUE standardisation of the southern Indian Ocean Saint-Paul and Amsterdam rock lobster

This study reports on the analysis of long-term temporal trend in Catch Per Unit Effort (CPUE) for rock lobster caught in Saint Paul and Amsterdam (SPA) islands. CPUE standardization was performed using generalized linear models (GLM) fitted on catch and effort data for the period 1980-2019. Lognormal model was used to standardize the nominal CPUE using fishing year, fishing period, fishing area, and fishing year-area interactions as exploratory variables. For both islands a decline of standardised CPUE was observed at the beginning of the series followed by a relative stable trend with low variability until the recent years where an increase has been observed. The recent increase in both islands has been mainly driven by the offshore areas while a slight decline in the coastal area has been observed since 2016. These results suggest that the current stock level of the exploitable biomass of lobster in Saint Paul and Amsterdam have slightly increased in recent years