SUMMARY: Artificial collection of early juveniles ("spat") of the scallop Argopecten purpuratus in Japanese-type collectors was evaluated between January 2001 and July 2002 in the La Rinconada Marine Reserve, Antofagasta, Chile. This area of Antofagasta Bay has in the past been noted for the retention of scallop larvae by local gyres, in which their numbers can vary between 89 and 34175 larvae m -3 , producing larval sets of 400 to 15340 post-larvae (spat) per collector. The results showed no quantitative relationship between larval abundance in the water and the spat density collected per day in the collectors, although high settlement rates were associated with high numbers of umboned larvae in the water. Allowing collectors to remain in situ for extended periods of 88 and 159 days resulted in a severe loss of seed which had settled in the collectors during the first 28 to 40 days of immersion. These losses varied between 50.9 and 99.6% of the spat collected, and were more prejudicial for the smaller cohorts that had settled in the collectors at the end of the first immersion period. The growth rates measured among different cohorts for each immersion period varied between 81.3 and 235.2 μm/day for the first cohort (C 1 ) and between 64.0 and 167.4 μm/day for the second cohort (C 2 ). The highest growth rates occurred in collectors containing the lowest numbers of spat after the occurrence of spat losses during the long periods of immersion. Occurrence of intraspecific competition within the collectors is discussed as potentially responsible for the decreases in spat numbers and the variations observed in their growth rates. No se encontró una relación directa entre abundancia larvaria y asentamiento, sin embargo, las mayores captaciones estuvieron asociadas a la presencia de un elevado número de estados umbonados. La mantenimiento prolongado de colectores in situ, por periodos que variaron entre 88 y 159 días, provocó una fuerte reducción en el número de semillas que se asentaron en ellos durante los primeros 28 a 40 días de inmersión Estas reducciones variaron entre el 99.6 y el 50.9% de la semilla fijada, siendo las más perjudicadas las cohortes más pequeñas, asentadas al final del primer periodo de inmersión. Las tasas de crecimiento registradas en estas cohortes, para cada periodo de inmersión, variaron entre 81.3 y 235.2 μm/día para las cohortes C 1 y entre 64.0 y 167.4 μm/día para las cohortes C 2 . Las mayores tasas están directamente relacionadas con un menor número de semilla recuperada. Se discuten las competencias intraespecíficas ocurridas en los colectores, como responsables de la disminución del número de semilla y de las variaciones registradas en sus tasas de crecimiento.
Se presentan los parámetros de crecimiento L ∞ = 120.38 mm y K = 0.9668 para el banco de Argopecten purpuratus de la Reserva Marina La Rinconada (Antofagasta, Chile), obtenidos entre marzo de 2001 y mayo de 2003 usando métodos de marcaje y recaptura de ejemplares. La elevada recaptura de individuos marcados (60-80%) indica baja mortalidad natural y una conducta sedentaria del recurso. Las evaluaciones anuales realizadas para estimar el tamaño del banco confirmaron tal conducta, encontrándose la mayoría de los individuos agregados en el centro, con densidades que variaron entre años de 9 a 14.8 ind m-2 .
ARTÍCULO Evaluación del desempeño de la primera reserva marina de Chile, La Rinconada, en el ámbito de la conservación de su especie focal, el ostión del norte Argopecten purpuratusEvaluation of the performance of the first marine reserve in Chile, La Rinconada, in the field of conservation on its focal species, the scallop Argopecten purpuratusAbstract.-We evaluated the performance of the first marine reserve in Chile, created in La Rinconada, Antofagasta, based on biotic indicators (abundance; population structure and recruitment success) of its focal species the scallop Argopecten purpuratus. This was attained by analyzing species population information, acquired during 2001, 2002, 2005 and 2009, by direct assessment diving, and on spat settlement into artificial collectors. The results show variation in the density of the specimens, which strongly affects the total abundance of the population, with a significant decrease in their average size in time, which is a decrease of individuals on the minimum legal size (90 mm) from 2.6 x 10 6 individuals in 2001 to 1.5 x 10 5 individual in 2009. This reduction has generated a drastic decline in their spawning stock, which has seriously impacted on the uptake of seed, descending from 15,340 ind. collector -1 in 2001 to 1,157 ind. collector -1 in 2009. The analysis of these results through 3 indicators, indicates that the measures of conservation have failed to recover its density and size structure, to enhance the availability of seeds and breeding adults, which were the main purposes for the creation of this marine reserve. While the main reason that inspired its creation was the conservation of the resource A. purpuratus, this measure has resulted in increased interest for illegal exploitation.The need for implementing measures that allow effective participation is concluded, with equity regarding resource utilization, considering that after 20 years of fishing ban, regulatory measures imposed by the State, have not had the expected results.Resumen.-Se evalúa el desempeño de la primera reserva marina de Chile, creada en La Rinconada, Antofagasta, en base a los indicadores bióticos (abundancia; estructura poblacional y éxito del reclutamiento) de su especie foco de conservación, el pectínido A. purpuratus. Se utilizó información de la población de esta especie en 2001, 2002, 2005 y 2009, obtenida mediante evaluación directa por buceo, y del asentamiento de semilla sobre colectores artificiales. Los resultados muestran variación en la densidad de los ejemplares, que repercute fuertemente en la abundancia total de la población, con una disminución significativa de su talla media, y de los individuos sobre la talla mínima legal (90 mm) que se redujeron de 2,6 x 10 6 en 2001 a 1,5 x 10 5 en 2009. Esta reducción ha generado una disminución drástica de su stock desovante, afectando seriamente la captación de semilla, que ha descendido de un máximo de 15.340 ind. colector -1 el 2001, a 1.157 ind. colector -1 el 2009. El análisis de estos resultados bajo el prisma de 3 indic...
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