Distribution, development, and metabolism of larval stages of the warmwater shrimp, Caridina babaulti basrensis (Decapoda, Atyidae)

Abstract

Peak release of zoea I larvae of the warmwater shrimp, Caridina babaulti basrensis (Al-Adhub AHY 1987) in the field coincided with the highest summer water temperature (33°C). Zoea I abundances did not correlate significantly with the phase of the lunar cycle (p = 0.256) and only slightly with time of day (day : night regimes, p = 0.079). Temperature correlated significantly with zoeae I larval release in the field (p < 0.0001). Development and respiration were measured at constant water temperatures ranging from 20 to 35°C in coordination with the temporal distribution of larvae in the field. Cumulative duration for the development of the larval phase of C. babaulti basrensis was 11.4, 7.7, and 6.1 days at 25, 30, and 35°C, respectively. Larvae were unable to complete development at 20°C. Respiration rate for larval C. babaulti basrensis increased in direct proportion to temperature, and revealed metabolic stress at high temperatures. Laboratory rearing supported field data, which indicated a constraint on the presence of stage I zoeae in the plankton at lower temperatures (20°C). Although some larval stages may be metabolically stressed at higher temperatures, rapid development rates accomplished at higher temperatures may be a likely mechanism for retention within the habitat and recruitment to the adult population.