Temporal variation in growth rates and reproductive parameters in the small near-shore tropical squid Loliolus noctiluca; is cooler better?

Abstract

Seasonal growth rates and size- and age-at-maturity were analysed for the small near- shore tropical loliginid squid Loliolus noctiluca off North Queensland, Australia, over a period of 2 yr. Age of individuals was determined using daily statolith increments. The life cycle of L. noctiluca off North Queensland was just over 4 mo. Analysis of growth found that growth was non-asymptotic, and the form of the curve; exponential, linear or log-linear, depended on sex and season that individuals were caught. Winter-caught individuals were the fastest growing and achieved the largest size com- pared with summer or autumn-caught individuals. Furthermore, females grew faster than males dur- ing the winter. The patterns of growth of L. noctiluca were compared between tropical North Queensland and temperate New South Wales. The temperate individuals lived longer and had slower growth rates. There was also a marked seasonal influence on the onset of sexual maturity among the North Queensland population, with the fastest growing winter-caught individuals matur- ing later than the autumn or summer individuals. L. noctiluca has a large latitudinal range from New Guinea to Tasmania, this study, and published work, suggests a trend towards increased lifespan and decreased growth rate with increasing latitude.