Variabilidad estacional de la distribución y abundancia de larvas de langostino colorado en la zona norte de Chile (Decapoda, Anomura, Galatheidae)

Abstract

RESUMEN.Se analiza la distribución y abundancia de los estadios larvales de langostino colorado Pleuroncodes monodon en la zona norte de Chile, capturados entre 0 y 100 m, en cuatro cruceros oceanográficos efectuados en enero, mayo, agosto y octubre de 2003, en un área adyacente a la desembocadura del río Loa (20°40'-21°20'S). Se realizó un total de 20 estaciones oceanográficas y las muestras zooplanctónicas se obtuvieron mediante redes Bongo desde la superficie hasta 100 m de profundidad, registrándose además datos de temperatura, oxígeno disuelto y densidad en cada estación. Los máximos de abundancia se registraron en enero y agosto, y el mínimo en mayo. En sentido norte-sur, las mayores abundancias se encontraron en las secciones situadas en el sector norte. No obstante, en octubre se observó una distribución de abundancia más homogénea. En sentido costa-océano se determinó un patrón diferenciado, con una preferencia oceánica de los estadios zoea III-V y megalopa. Además, se observó una tendencia estacional de los focos de mayor abundancia larvaria asociados a las estaciones con temperaturas medias de 14,0-16,0°C y a concentraciones medias de oxígeno disuelto de 1,58-4,55 mL·L -1 .Palabras clave: Pleuroncodes monodon, Galatheidae, estadios larvales, variabilidad espacio-temporal, abundancia, norte de Chile. Seasonal variability in the distribution and abundanceof larvae of the red squat lobster (Decapoda, Anomura, Galatheidae) from Northern ChileABSTRACT. An analysis was made of the distribution and abundance of red squat lobster (Pleuroncodes monodon) larvae off the mouth of the Loa River, northern Chile (20°40'-21°20'S) during oceanographic cruises in January, May, August and October 2003. A total of 20 oceanographic stations were occupied, with zooplankton samples taken using Bongo nets towed from the surface to 100 m depth. Other data obtained at each station included temperature, dissolved oxygen, and seawater density. Maxima of abundance of these larvae were recorded in January and August, with a minimum in May. On N-S tracks the highest abundances were recorded in the northern sector. A more homogeneous distribution of abundance was observed in October. On E-W tracks a differentiated pattern was observed, where zoea stages III-V and megalopae occurred in the oceanic (westward) samples. Also, a seasonal tendency was noted, with foci of larval abundance associated with stations having average temperatures of 14.0-16.0°C and dissolved oxygen concentrations of 1.58 -4.55 mL·L -1 .

Variation in cheliped form in two species of squat lobsters (Decapoda: Anomura) from Chile

“…In spite of being target of a trawl fishery operating on the continental margin along the Chilean coast, the general biology of these two species is only poorly known (THIEL and LOVRICH, 2011). Few studies have focused on the reproductive biology of these species, especially in P. monodon: PALMA (1994) and RIVERA and SANTANDER (2005) have reported the presence of larval stages in the plankton, and PALMA and ARANA (1997) have studied the developmental stages of embryos in the egg mass. ESPINOZA-FUENZALIDA et al (2012) reported that females of both species mate during the intermolt period and become receptive shortly after having released larvae from a previous brood, when they form pairs with males.…”

Annual brood number and breeding periodicity of squat lobsters (Decapoda: Anomura: Galatheidae) from the continental shelf of the SE Pacific—Implications for fisheries management

“…This number is substantially higher than previous estimates for both species (1-2 broods), which were based on indirect methods such as the proportion of ovigerous females, the developmental stages of incubated embryos, or the presence of larval stages in the plankton (Palma, 1994;Palma and Arana, 1997;Rivera and Santander, 2005). The high proportion of females from the field that readily produced a new brood in the laboratory environment confirms that female squat lobsters indeed produce more than one annual brood in the field.…”

“…However, females with late-stage embryos are already found during the peak of the reproductive period and females with early-stage embryos are still observed toward the end of the annual reproductive periods (Wolff and Aroca, 1995;Palma and Arana, 1997). Similarly, late-stage larvae already appear in the plankton early during the reproductive season, while early-stage larvae are still found late in the annual reproductive period (Palma, 1994;Rivera and Santander, 2005;Mujica et al, 2011;Yannicelli et al, 2012). All this indirect evidence strongly suggests that females might produce more than one annual brood.…”

Breeding behavior and sex ratio variation of Pleuroncodes monodon (Crustacea: Galatheidae) off the Peruvian coast

“…Along the coast of South America, it is distributed from Lobos de Afuera Island (~06º S), Peru, to Ancud Bay (~42º S), Chile (Chirichigno 1970). Its depth distribution is conditioned by the oceanography of the region and reproductive behavior (Rivera and Santander 2005). Under this premise, Palma and Arana (1997) determined the depth distribution of P. monodon females off the coast of Chile, and found that at the beginning of the egg-carrying period (autumn) they inhabit deeper waters, between 200 and 350 m depth, and at the end of winter they migrate to shallower waters, between 70 and 200 m depth, where the highest percentage of ovigerous females was recorded.…”

“…Palma and Arana (1997) recorded that egg carrying peaked between May and late October off the coast of Concepción, Chile. Rivera and Santander (2005) determined that the reproductive stage of P. monodon occurs with greater incidence in winter (August). In the case of the pelagic red crab, Pleuroncodes planipes, from the North Pacific, the egg-carrying period extends from December to April (Boyd and Johnson 1963).…”