Growth, molt and survival of Palaemonetes argentinus (Decapoda, Caridea) under different light-dark conditions

Abstract

Growth, survival and molting rate in Palaemonetes argentinus Nobili, 1901 were compared under different light-dark conditions. During 80 days, 150 immatures of both sexes (initial mean weight 0.09±0.002g), from Los Padres lagoon, Mar del Plata, Argentina, were maintained in aquaria at 19±0.4°C under three light conditions: 0:24, 10:14 and 13:11 (L-D). They were fed daily on an artificial diet (45% proteins, 17.2% lipids, 7% water, 7% ash). Good weight increment was obtained with the three treatments, finding a positive linear correlation between mean weight and time (0:24, r=0.97; 10:14, r=0.99; 13:11, r=0.98). There were no significant differences in the percentage increment in mean weight among the treatments (0:24, 19.3%; 10:14, 29.3% and 13:11, 26.5%) (p<0.05). Molting rate was significantly higher at a long-day photoperiod (MR=1.7) than at a shortday (MR=0.6) or continuous dark condition (MR=0.3) (p<0.05). The lowest survival was found in animals maintained under 13:11 L-D conditions (77%), being statistically different of the other two treatments (92% and 89% at 10:14 and 0:24, respectively) (p<0.05). These results suggest that the best growth and survival in P. argentinus result with a 10:14 L-D cycle, and that the growth is less affected by photoperiod than molting rate and survival.

Energy reserves mobilization: Strategies of three decapod species

“…This could be because a high molt rate would imply a high metabolism and, therefore, greater energy requirements would be needed during starvation to maintain homeostasis. In our three studied species molting frequency is variable: 40 d -1 [ 57 ], 45–50 d -1 (Sacristan unpublished data), and 2 yr -1 [ 28 ] in Palaemon argentinus , Cherax quadricarinatus and Munida gregaria respectively, and therefore this coincides with the type of reserve mobilized during starvation for the three species.…”

Crescimento de Aegla itacolomiensis (Crustacea, Decapoda) em um arroio da Mata Atlântica no sul do Brasil

“…A taxa de crescimento dos animais pode estar diretamente ligada a fatores abióticos que exercem influência sobre os indivíduos de uma população, podendo inclusive desencadear ou alterar processos fisiológicos relacionados entre outros, aos eventos da reprodução e ao crescimento (DÍAZ et al, 2003, CREAR et al, 2003. No presente trabalho, registrou-se que os machos de A. itacolomiensis possuem uma taxa de crescimento mais elevada do que as fêmeas.…”

Setogenesis and characterization of the new moult substages in the freshwater shrimp Palaemon argentinus (Nobili, 1901) (Caridea: Palaemonidae)

“…This rapid growth rate in optimum temperatures may be associated with increased food consumption (Wyban et al, 1995), which was widely available for the species under study. Moreover, according to Díaz et al (2003), a 13h/11h light/dark photoperiod favors the moult frequency, and our laboratory conditions were similar to this photoperiod.…”