Data-mining of blue shark length of north and south Atlantic stocks from the Spanish surface longline 1997-2021

The paper summarizes the length data-mining carried out in recent years in order to obtain a broad overview of the average length over time of the blue shark (Prionace glauca) between years 1997-2021 for the North and South Atlantic stocks. The data-mining was carried out through an intense compilation of records from samples on board commercial trips, experimental and tagging surveys, personal notes from skippers that were voluntarily provided for this scientific contribution through a collaborative science action, as well as through sampling during landings. The length data series was analyzed using GLM models to obtain relative and standardized trend of the mean length over time. The results showed a stable trend of the mean length and a slightly upward in the most recent period for both stocks.