Catch-Per-Unit-Effort standardization for the southern Atlantic blue shark (Prionace glauca) based on Brazilian and Uruguayan longline fishery Data (1990-2022)

Catch and effort data from Brazilian and Uruguayan tuna longline fishery in the South Atlantic Ocean from 1978 to 2022 were analyzed. The effort was distributed in a wide area of the western Atlantic Ocean. The CPUE of the southern blue shark was standardized by a GLM using a Delta Lognormal approach. The factors used in the models were: year, quarter, flag, vessel, hooks per floats, hooks, and the lat-long reference for each five by 5 degrees square. After the data cleaning, an index was estimated for the period between 1992 to 2022. The estimated delta-lognormal index showed three distinct periods. Between 1992 and 2005, the index was marked by stable smooth and low values. The second one, from 2006 to 2012, presented a slight increase in relative abundance attaining its peak in 2012. The third period, from 2013 to 2022, showed a dynamic pattern with higher values than the beginning of the series but without any apparent increase or decreasing trend.