Distribution and abundance of Heterocarpus reedi Bahamonde, 1955, Cervimunida johni Porter, 1903, and Pleuroncodes monodon (H. Milne Edwards, 1837), larvae off Coquimbo and Caldera, Chile

Abstract

To better understand the population dynamics of fishery resource species, 160 zooplankton samples were obtained with a Bongo net at 40 oceanographic stations around Caldera and Coquimbo in October and December, 2005, and analyzed. All crustacean decapod larvae were sorted, and Heterocarpus reedi, Cervimunida johni, and Pleuroncodes monodon larvae were identified. For all three species, the highest abundances of early zoea were found in October in Coquimbo, whereas advanced larval stages were predominant in December. In Caldera, advanced larval stages of H. reedi and P. monodon, and early zoeas of C. johni were dominant during both sampling months. The frequency of occurrence of H. reedi larvae was similar during both sampling months in Coquimbo and greater in October in Caldera. The frequency of occurrence of the larvae of P. monodon and C. johni was greater in both areas in October. All the megalops captured in both zones and sampling months corresponded to a single morphotype, with morphological characteristics similar to the smallest P. monodon juvenile specimens. Based on the larval distribution and abundance of these three species, it is postulated that spawning occurs earlier in the Caldera area than around Coquimbo, mainly in areas near the coast, given the differences in abundance of the developmental stages.