EFFECT OF STARVATION ON THE FIRST LARVAE OF HOMARUS-AMERICANUS (DECAPODA, NEPHROPIDAE) AND PHYLLOSOMAS OF JASUS-VERREAUXI AND JASUS-EDWARDSII (DECAPODA, PALINURIDAE)
Fa. Abrunhosa et J. Kittaka, EFFECT OF STARVATION ON THE FIRST LARVAE OF HOMARUS-AMERICANUS (DECAPODA, NEPHROPIDAE) AND PHYLLOSOMAS OF JASUS-VERREAUXI AND JASUS-EDWARDSII (DECAPODA, PALINURIDAE), Bulletin of marine science, 61(1), 1997, pp. 73-80
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.