15 DECEMBER 1999
M.K. Gullian, W.Q. Seiffert, E. Beltrame
Two experiments were performed at the Laboratory of Marine shrimp at Federal University of Santa Catarina (Brazil) with the objective to analyse the tolerance of Litopenaeus vannamei at low temperature and to determine at what temperature it stops feeding itself .
In the first experiment, the survival of postlarvae in the stages 21 and 31 was evaluated. Each postlarval stage was submitted to an acclimation procedure to the temperatures 7, 10, 13, 16, 19 C and kept in these temperatures for a 24 hours period. After this period, the survival data from the experimental unit and the related treatments were transformed in arcsine and compared through statistic analysis. No statistic differences were observed (p>0.05) among the larval stages related to the survival data obtained. However statistic differences were found (P< 0,05) among the studied temperatures referring to the survival data. The survival data were also submitted to a linear regression analysis for different analysed temperatures, being found in the surviving equation Y = -43,5399 + 7.88122 X. From the curve obtained throughout the polynomial regression it was possible to determine that the 11,2 C temperature fits into the lethal temperature (LT50) for L. vannamei post larvae. The second experiment was designed to evaluate the survival and stop rate of food consumption in juveniles (9,7g +\- 2.8). They were submitted to an acclimation procedure throughout the temperatures 7, 10, 13, 16, 19, 22, 25, 28 C and kept in these temperatures for a 24 hours period. After this period, the temperature data where food consumption stopped was found under the 16 C. However 100% survival was found from 13 C during the whole experimental period. The results obtained with this experiment reaffirm the capability that L. vannamei has of supporting low temperatures and keeping banks of reproducers and postlarvae in regions where geographical latitudes do not reach the lethal temperature.
(LCM, Laboratorio de Camarones Marinos, Depto. de Acuicultura, Centro de Ciencias Agrarias, Universidad Federal de Santa Catarina, Brazil, e-mail: ecalcm@mboxl.ufse.br)