Abstract:The size and spatial distribution of the blue shark, Prionace glauca, were described
based on 3942 specimens, that were collected by scientific observers on-board
Taiwanese large-scale tuna longline fleets in the North Pacific between June 2004 and
December 2014. Size segregation was found, and the mean size of blue sharks in the
tropical and subtropical area (0-30 °N) was significantly smaller than those in the
temperate area (north of 30 °N). No significant sex segregation was found. Males
predominated in the size range of 210-290 cm TL in the temperate area and in the
range of 230-310 cm TL in the tropical and subtropical area.