Effects of live and prepared feeds on postlarval stages of Pleoticus muelleri Bate (Crustacea, Penaeoidea)
J.L. Fenucci, J. C. Mallo
Abstract:
The red shrimp Pleoticus muelleri has a
distribution along the South American coastal waters from, Brazil (23°00'S)
to Patagonia, Argentina (49°45'S). This species has high commercial value
but has had yearly fluctuations in catches. It is therefore important to
establish the possibility of culturing on commercial basis. Since one of the
main problems in postlarval production in hatcheries is feeding the early
postlarval stages the aim of this work was to find a diet that promotes
optimal growth and survival of the early postlarval stages of
this species. Two experiments were run in 10-liter
fiberglass containers, the first using one-day postlarvae (PL 1) and the
second animals of 10 days (PL 10). The postlarvae were obtained from the
hatchery of the University of Mar del Plata. The following feeds were tested
in duplicate: A. Live naupliar stages of Artemia sp.; B. Dry Artemia
flakes enriched with unsaturated fatty acids; C. A commercial
microencapsulated feed and D. A microencapsulated prepared at the
laboratory. Water was changed 100% daily and all the tanks were supplemented
with Chaetoceros gracilis and Tetraselmis chuii. The temperature ranged from
17 to 20°C and 19 to 22°C during the first and second experiment,
respectively. Salinity was 33%o. Total length and weight of animals were
determined at the beginning and at the end of the experiments. In the first
experiment the best growth in total length, mean weight and survival were
found in shrimp fed with live naupliar Artemia, these results were
significantly higher than those obtained with the other feeds. In the second
experiment, after 15-day trial, the best growths in total length and mean
weight were obtained feeding the feeds B, C and D. Also the best survivals
between 70.2 and 76.5% were obtained with these treatments, while survival
in treatment A was 56.5%.
These results stress the importance of adequate
feeding of postlarval stages according with their changes in habitat, since
postlarval stages of Pleoticus muelleri change from planktonic to
bentonic habits between PL7 and PL 11. On the other hand, these findings
allow to obtain high quality PL20 the age at which the shrimp are stocking
in the nursery ponds.
(Facultad.
de Cs. Exactas y Naturales, Depto. de
Cs. Marinas,
UNMP/CONICET. Funes 3350 (7600) Mar del Plata, Argentina, e-mail: jfenucci@mdp.edu.ar)