EFFECT OF STARVATION ON THE FIRST LARVAE OF HOMARUS-AMERICANUS (DECAPODA, NEPHROPIDAE) AND PHYLLOSOMAS OF JASUS-VERREAUXI AND JASUS-EDWARDSII (DECAPODA, PALINURIDAE)

Food is one of the important factors controlling decapod larval cultur e, however, little is known about the effect of the starvation regimen on the physiological condition of the larvae. In the present study, t he influence of starvation upon survival rate and the intermolt period was observed in the first instar of the American lobster, Homarus ame ricanus, the first instars of phyllosomas of the red rock lobster, Jas us edwardsii, and the green rock lobster, J. verreauxi. Larvae were re ared in receptacles of 150 ml capacity filled with sea water and submi tted to two feeding regimens: larvae were submitted to an initial peri od of starvation and larvae were submitted to an initial period of fee ding. Larvae of H. americanus were cultured individually at 17-18 degr ees C, while phyllosomas were cultured at five larvae per receptacle a t temperatures of 19-22 degrees C and 16-17 degrees C for J. edwardsii and J. verreauxi. respectively. No larvae succeeded in molting if com pletely starved or if they were fed after a prolonged starvation perio d. However, the species showed a period of tolerance before food was i ntroduced. The average interval between the first day of feeding and t he first day of molting was relatively constant within each species: a bout 4, 10 and 12 d for H. americanus, J. edwardsii and J. verreauxi, respectively. The starvation tolerance period (50% survival) averaged about 5, 4 and 8 d for these species, respectively. The interval betwe en the ending of starvation and the initial molting period were roughl y equivalent although it was shorter in H. americanus than in the Jasu s species. The beginning of molting in each species was delayed in acc ordance with prolonged days of starvation. The feeding period that all owed at least 50% of the larvae to molt to the 2nd instar was 1, 5 and 7 d for these species, respectively. Molting in each species began af ter a rather constant intermolt period (5, 12, 13 d, respectively), re gardless of the length of the initial feeding period. These results in dicate that the first instar phyllosoma of these Jasus spp. are less t olerant of starvation and require a longer feeding period to molt comp ared to Homarus larvae.