Growth, hatch size and maturation in a southern population of the loliginid squidLoliolus noctiluca

Abstract

Age, growth and cost of reproduction were examined for the small near-shore loliginid squidLoliolus noctilucain Tasmanian waters, near the southern limit of its distribution. The effects of several factors on hatch size were also evaluated by comparing the statolith natal ring size (NR) from individuals collected in different locations, seasons and years. The life cycle ofL. noctilucawas less than six months. July-hatched females grew faster than their May-hatched counterparts, indicating a faster growth in winter-hatched compared with autumn-hatched individuals. There was considerable variation in NRs as function of location, season, year and sex, with females displaying NRs considerably larger than males in any location and year. Immature and maturing females displayed poorer body condition than mature counterparts, suggesting that gonad growth does not affect the mantle or fin growth. A good condition was maintained also in spent individuals indicating thatL. noctilucacontinued to invest in somatic organs throughout the spawning period. A reproductive strategy closer to ‘multiple spawning’, than to ‘single spawning’ was proposed for this species.Loliolus noctilucawas used as a model to explore the possible effects of climate change on near-shore loliginid populations.