Ecological Patterns, Distribution and Population Structure of Prionace Glauca (Chondrichthyes: Carcharhinidae) in the Tropical-Subtropical Transition Zone of the North-Eastern Pacific

Abstract

Regional ecological patterns, distribution and population structure of Prionace glauca were analyzed based on samples collected on-board two long-line fleets operating in oceanic waters (1994e96/2000e 02) and in coastal oceanic waters (2003 e2009) of the eastern tropical Pacific off México. Generalized additive models were applied to catch per unit of effort data to evaluate the effect of spatial, temporal and environmental factors on the horizontal distribution of the life stages (juvenile, adult) and the sexes at the estimated depth of catch. The presence of breeding areas was explored. The population structure was characterized by the presence of juveniles aggregations and pregnant females towards coastal waters and the presence of adult males.