Journal of the Marine Biological Association of India

Volume 52 Issue 2
Higher water temperature leads to precocious maturation of western rock lobsters (Panulirus cygnus), but are things that simple?
*R. Melville-Smith, 1S. de Lestang and 1D. J. Johnston
Abstract
During a rock lobster post-puerulus grow out project, western rock lobsters from three different cohorts (post-puerulus, year-1 and year-2)were held for 12 months under two temperature regimes(ambient
and 23° C) and two feed delivery treatments (the same ration of pe-lleted diet fed once nightly and in the alternate treatment,thrice nightly). At the end of the trial, 43% of females from the largest cohort (2-year post settlement) in the 23oC treatment, had ovigerous setae. However, none of the animals held at ambient temperatures showed signs of maturity. Feed delivery did not influence the pre-sence or absence of ovigerous setae. Male maturity responded to ele-vated temperature in the same way as for females, as indicated by merus/carapace length ratios.The response of female size at maturity to 23° C was compared to a similar trial in the 1970s in which 2-year post settlement animals were held at 25° C.Maturity of fe-males in that study was one year later than in the trial reported here, in-dicating that there may have been a decrease in age at maturity since the 1970s. The conclusion from this and research on other rock lobster species, is that size/age at maturity is likely to be complex response to a range of contributing factors of which tempera-ture is an important one.
Keywords
Maturity, life history, aquaculture, Bergmann's rule
Date : 03-03-2011