Effects of temperature and
salinity on artificially reproduced eggs and larvae of the leopard grouper Mycteroperca
rosacea
V. Gracia-López, M. Kiewek-Martínez, M.
Maldonado-García-2004
Aquaculture, 237(1-4): 485-498
Abstract:
The effects of temperature and salinity on eggs and
larvae of the leopard grouper, Mycteroperca rosacea, were studied.
Eggs from hormone-induced spawning were artificially fertilized. The effect
of temperature (20, 24, 26, 28, and 30 °C) on hatch rate, notochord length,
yolk sac volume, and oil droplet diameter was recorded. Times from
fertilization to 50% hatch and hatching period duration (first to last
hatch) were also recorded for each temperature. The effect of temperature
(20, 24, 26, and 28 °C) on survival, growth rate, and final larval lengths
5 days after fertilization was demonstrated. The effect of salinity (0‰,
8‰, 16‰, 24‰, 32‰, 40‰, 48‰, 56‰, and 64‰) on hatching rate
and larval lengths at hatch was recorded. Additionally, the effect of
salinity (0‰, 10‰, 20‰, 30‰, and 40‰) on survival and growth of
larvae until total absorption of the yolk sac was demonstrated. Also, egg
buoyancy at different salinities was established. Results indicate better
hatching rates (70–78%) in temperatures ranging from 24 to 30 °C than at
20 °C. The notochord length of newly hatched larvae was inversely related
to temperature and to the oil droplet diameter. Larvae that hatched at 20 °C
were the longest and had the smallest oil droplet diameters and yolk sac
volumes. The largest yolk sac volumes were observed at 26 and 28 °C.
Times from fertilization to 50% hatch and hatching
period duration decreased with increasing temperature. A higher larval
growth rate to day 5 after fertilization was obtained at higher
temperatures. Eggs maintained at 32‰ salinity showed the best hatching
rates (80.7%). In the salinity growth trial, final notochord lengths of the
larvae were inversely related to salinity. Eggs were buoyant at salinities
above 34‰.