Evidence of summer parturition in shortfin mako (Isurus oxyrinchus) sharksfrom New Zealand waters

A litter of eight near-term shortfin mako (Isurus oxyrinchus Rafinesque 181 0) embryos is described from a 317.5 cm total length (TL) female caught off Hawke Bay, south-east North Island, New Zealand on 5 February 1999. The em bryos (3 males and 5 females) were 67.2-77.0 cm TL. Embryo length, conditio n, hepato-somatic indices. and mass of yolk in their stomachs all indicate they were close to birth. This is the first shortfin make litter reported f rom New Zealand and is outside the late winter-early spring parturition per iod predicted from estimated embryonic and juvenile growth rates. Uterine w idth data from four mature non-pregnant females and age-0+length-at-capture data suggest parturition occurs from September to late February (late wint er-mid summer) but is infrequent after January. We suggest that shortfin ma kos have an extended parturition period, possibly year-round, with peak par turition occurring in late winter-spring.