RESUMEN. Se analiza la distribución vertical y abundancia de larvas de crustáceos decápodos planctónicos en canales orientales de la isla Chiloé. Se relaciona la distribución de larvas con la hora de captura y marea, que interferirían con las migraciones verticales u ontogénicas descritas para el meroplancton. De las especies identificadas, las larvas de Neotrypaea uncinata fueron las más abundantes. Su distribución vertical, fue inversa a la descrita para la migración circadiaria de zooplancton, sin que se encontraran diferencias significativas en la abundancia en los dos estratos de profundidad. Las abundancias de larvas de Cancridae y Pinnotheridae, fueron las únicas que tuvieron diferencias significativas en ambos estratos, aunque inversas al patrón de distribución vertical circadiaria. La amplitud de marea y dinámica oceanográfica descrita para los canales del área de estudio, serían determinantes en la distribución de las larvas en el sector, sobreponiéndose el transporte de ellas al comportamiento migratorio descrito para el zooplancton en general. Palabras clave: larvas de decápodos, distribución vertical, canales australes, Chile. Vertical distribution of planktonic decapods crustacean larvae in oriental channels of the Chiloé Island, ChileABSTRACT. The vertical distribution and abundance of planktonic decapods larvae in channels from the inside part of Chiloé Island is analyzed. The larvae distribution is related with the capture daytime and the tide conditions and which could interfere with the vertical or ontogenic migrations described for the meroplankton. From the identified species, the Neotrypaea uncinata larvae were the most abundant. Their vertical distribution was inverse to the one described by the circadian migration of the zooplankton, without detecting significant differences among the abundances in both sampled strata. The abundance of Cancridae and Pinnotheridae larvae were the only ones that had significant differences in the two strata, although they were inverse to the pattern of circadian vertical distribution. The tide height and the oceanographic dynamic described for the channels of the area under study would be decisive in the distribution of larvae in the sector, overcoming their transport to the migratory behavior described for the zooplankton in general.
Resumen.-El desarrollo embrionario y larval de Dissostichus eleginoides es descrito por primera vez utilizando ejemplares cultivados en laboratorio (4 a 8°C). Periódicamente fueron fijados huevos y larvas para describir el desarrollo. Los huevos midieron de 3,1 a 3,5 mm de diámetro, esféricos, de corion transparente y superficie levemente rugosa, con 28 gotas oleosas, ubicadas en torno al polo germinativo y tardaron 30 a 33 días en eclosionar. Las larvas consumieron el saco vitelino en 18 días (larvas vitelogénicas, 8-13 mm), luego comienzan a desarrollarse los rayos de las aletas, se incrementa la pigmentación y se distinguen 3 zonas con agregación de melanóforos (parte posterodorsal de la cabeza, sobre el intestino y delante del pedúnculo caudal). El complejo hipural a estuvo completamente formado cuando las larvas midieron entre 49 y 53 mm (LS), lo que ocurrió a 57 días de la eclosión. Palabras clave: Dissostichus eleginoides, desarrollo embrionario y larvalAbstract.-This is the first description of the embryonic and early larval development of laboratory-reared (4-8°C) Dissostichus eleginoides. Specimens were periodically sampled to describe egg and larval development. Eggs were spherical (3.1-3.5 mm diameter) and had a transparent chorion and slightly rough surface, with 28 oil globules located around the germinal pole. Eggs incubated between 30 and 33 days until hatching. At day 18 post-hatching, the yolk sac was absorbed by vitellogenic larvae (8-13 mm total length), after which, the fin rays started to develop, pigmentation increased, and main melanophore aggregation zones were distinguished on the posterodorsal part of the head, the intestine, and before the caudal peduncle. The hypural complex was fully formed by day 57 post-hatching (49-53 mm standard length).
ABSTRACT. The larvae of Emerita analoga, captured on the northern coast of Chile, during three consecutive years, during the austral summer, were separated by stage of development and their abundance, occurrence, and distribution, was analyzed for its proximity to the coast. The highest abundance was determined in coastal sampling stations and near the main sandy beaches of the study area, where the initial developmental stages were predominantly represented. The intermediate development stages proportionally increased in abundance at sampling stations in remote coastal stations, while more developed individuals had similar distribution than the first zoeae. Statistical analysis established significant differences in abundance, dominance, and occurrence of the different stages with respect to its distance to the coast. The Coquimbo Bay system had the highest concentrations of larvae, which has been associated with adult populations and oceanographic dynamics of the area. Spatial segregation of developmental stages and oceanographic dynamics of the area of greatest abundance would suggest that larval dispersion and retention are associated with water flows and circadian and ontogenetic vertical migration. Keywords: Emerita analoga, larval stages, larval dispersion, distribution, northern Chile. Dispersión de larvas de Emerita analoga (Stimpson, 1857) en la costa norte de Chile (25°-31,5°S)RESUMEN. Las larvas de Emerita analoga, capturadas en la costa norte de Chile en tres años consecutivos, durante el verano austral, se separaron por estado de desarrollo y se analizó su abundancia, ocurrencia y distribución respecto a su proximidad a la costa. La mayor abundancia se determinó en las estaciones costeras y próximas a las principales playas de arena de la zona de estudio, donde predominaron los primeros estados de desarrollo. Los estados intermedios de desarrollo incrementaron su abundancia proporcionalmente en las estaciones más alejadas de la costa, mientras que los más desarrollados tuvieron similar distribución que las primeras zoeas. El análisis estadístico, estableció diferencias significativas entre la abundancia, dominancia y ocurrencia de los distintos estadios, respecto de su distancia a la costa. El sistema de bahías de Coquimbo, tuvo las mayores concentraciones de larvas, lo que ha sido asociado a las poblaciones de adultos y dinámica oceanográfica de la zona. La segregación espacial de los estados de desarrollo y la dinámica oceanográfica de la zona de mayor abundancia, permite postular que la dispersión y retención larval, está asociada a flujos de agua y migración vertical circadiana y ontogénica. Palabras clave: Emerita analoga, estados larvales, dispersión larval, distribución, norte de Chile.
The presence of a Palinuridae phyllosoma larvae near Salado Bay (27º'S) north-central coast of Chile, is reported. The identification is discussed and the possibility of this larvae being Projasus bahamondei, which is the only species from the family that is described for the area, is discarded. The shape, size and position of the cephalic, pereionic, abdominal and telson appendices concords with descriptions of advanced stage Jasus frontalis larvae. Moreover, the specimen described here has five pairs of biramous pereiopods with setose exopods. In accordance with these observations and published data, it is proposed that this phyllosoma corresponds to a stage XII or XIII of J. frontalis larva.
Euphausia mucronata abundance and distribution of the developmental stages (calyptopis, furciliae, juveniles, and adults) was analyzed as a function of seawater temperature and chlorophyll-a concentration between Paposo (25°S) and Coquimbo (30°S), Chile. Zooplankton samples were obtained using bongo nets during February of three consecutive years (2014-2016). The Q coefficient was used to explore the relationship between the distribution and abundance of the development stages of E. mucronata with the temperature recorded throughout the water column. The adults were considerably more abundant than the rest of the ontogenetic development stages during the study period. The abundance of adults decreased from February 2014 to 2016, having a negative correlation with temperature. Relative abundance of juveniles and larvae increased positively related to the total euphausiid abundance. The Q coefficient showed a significant association of all development states concerning the low-temperature intervals recorded throughout the seawater column. Q coefficient showed no association with chlorophyll-a concentration through the recorded intervals throughout the water column and neither with the vertical abundance and distribution of E. mucronata specimens.
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