STANDARDIZED CATCH RATES IN BIOMASS FOR THE STOCK OF THE NORTH ATLANTIC BLUE SHARK (PRIONACE GLAUCA) CAUGHT BY THE SPANISH SURFACE LONGLINE FLEET IN THE PERIOD 1997-2013

• Main Authors: García-Cortés, Blanca, Ramos-Cartelle, Ana, Fernández-Costa, José, Mejuto-García, Jaime
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Blue shark; Centro Oceanográfico de A Coruña; Pesquerías; sharks; CPUE; GLM; Longline; Spanish fleet; North Atlantic
• Online Access: http://hdl.handle.net/10508/10367; http://hdl.handle.net/10261/322196

Standardized catch rates per unit of effort (CPUE) were obtained for the stock of the North Atlantic blue shark (Prionace glauca) using General Lineal Models (GLM) for a total of 5,639 trips of the Spanish surface longline fleet targeting swordfish, during the 1997-2013 period. The main factors considered were year, area, quarter, gear and ratio between swordfish and blue shark catches. The significant model explained the 84% of CPUE variability in blue shark. A major part of this variability was explained by the proxy of the targeting criteria, shown as the ratio between the two most prevalent species caught during the trip; swordfish and blue shark. Gear was identified as the second most important factor. Other factors were also significant, but less important. The standardized CPUE trend obtained suggests a stable trend of the North Atlantic blue shark stock and differs substantially from the nominal CPUE trends observed during the period considered. SI