Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile

Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile

Continuing studies at our Antofagasta (Chile) laboratory provided data from March 2001 to May 2003 on population parameters of Argopecten purpuratus in the scallop bed occupying the nearby La Rinconada Marine Reserve. Population growth parameters of L∞ = 120.38 mm and K = 0.9668 were obtain...

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Autores principales: Avendaño, M, Cantillánez, M
Format: Online
Jezik:eng
Izdano: Iniversidad Autónoma de Baja California 2005
Online dostop:https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/46
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record_format ojs
institution Ciencias Marinas
collection OJS
language eng
format Online
author Avendaño, M
Cantillánez, M
spellingShingle Avendaño, M
Cantillánez, M
Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile
author_facet Avendaño, M
Cantillánez, M
author_sort Avendaño, M
title Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile
title_short Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile
title_full Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile
title_fullStr Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile
title_full_unstemmed Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile
title_sort growth and population structure of argopecten purpuratus at la rinconada marine reserve, antofagasta, chile
description Continuing studies at our Antofagasta (Chile) laboratory provided data from March 2001 to May 2003 on population parameters of Argopecten purpuratus in the scallop bed occupying the nearby La Rinconada Marine Reserve. Population growth parameters of L∞ = 120.38 mm and K = 0.9668 were obtained using marking and recapture methods. The high recapture percentage (60–80%) of marked individuals indicates a low natural rate of mortality, as well as a sedentary behavior. Annual population estimates confirmed the sedentary behavior of the scallops, with most of the individuals concentrating towards the center of the bed at densities between 9–14.8 ind m–2. Scallop abundance showed interannual variation, with total individual counts ~10.1 × 106 in 2001, 8.2 × 106 in 2002, and 12.4 × 106 in 2003. Evaluations showed a reduction in mean size within the population from one year to the next, the mean length of 75.8 mm in 2001 decreasing to 62.1 mm in 2002 and to 51.7 mm in 2003. This decrease also occurred in the number of individuals of legal extraction size (90 mm), from 2.6 × 106 individuals in 2001 to 3.7 × 105 in 2003. Application of the growth parameters to the population structure in the bed showed recruitment of a new year-class of 6.5 × 106 individuals in 2002 and 11.2 × 106 in 2003. Subtraction of these numbers from the total numbers present in both years showed losses of about 8.4 × 106 individuals in 2002 and 7.0 × 106 in 2003. Based on the population growth parameters and supported by analysis of the catch curve using the Fisat program, these losses concerned the size range of scallops over 60 mm in length with a mortality Z = 2.15 in 2002 for individuals ranging from 67.5 to 115.5 mm in length and Z = 3.08 in 2003 for those ranging from 64.3 to 112.5 mm. The results suggest that the loss of scallops from these size ranges was due to human intervention (clandestine harvesting), also reported by wardens in the field. Illegal harvesting of this resource contravenes Chilean national legislation designed to conserve A. purpuratus and maintain its rational exploitation.
publisher Iniversidad Autónoma de Baja California
publishDate 2005
url https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/46
_version_ 1715723927967236096
spelling oai:cienciasmarinas.com.mx:article-462019-04-10T23:53:03Z Growth and population structure of Argopecten purpuratus at La Rinconada Marine Reserve, Antofagasta, Chile Crecimiento y estructura demográfica de Argopecten purpuratus en la Reserva Marina La Rinconada, Antofagasta, Chile Avendaño, M Cantillánez, M Argopecten purpuratus growth population structure marine reserve Chile Argopecten purpuratus crecimiento estructura demográfica reserva marina Chile Continuing studies at our Antofagasta (Chile) laboratory provided data from March 2001 to May 2003 on population parameters of Argopecten purpuratus in the scallop bed occupying the nearby La Rinconada Marine Reserve. Population growth parameters of L∞ = 120.38 mm and K = 0.9668 were obtained using marking and recapture methods. The high recapture percentage (60–80%) of marked individuals indicates a low natural rate of mortality, as well as a sedentary behavior. Annual population estimates confirmed the sedentary behavior of the scallops, with most of the individuals concentrating towards the center of the bed at densities between 9–14.8 ind m–2. Scallop abundance showed interannual variation, with total individual counts ~10.1 × 106 in 2001, 8.2 × 106 in 2002, and 12.4 × 106 in 2003. Evaluations showed a reduction in mean size within the population from one year to the next, the mean length of 75.8 mm in 2001 decreasing to 62.1 mm in 2002 and to 51.7 mm in 2003. This decrease also occurred in the number of individuals of legal extraction size (90 mm), from 2.6 × 106 individuals in 2001 to 3.7 × 105 in 2003. Application of the growth parameters to the population structure in the bed showed recruitment of a new year-class of 6.5 × 106 individuals in 2002 and 11.2 × 106 in 2003. Subtraction of these numbers from the total numbers present in both years showed losses of about 8.4 × 106 individuals in 2002 and 7.0 × 106 in 2003. Based on the population growth parameters and supported by analysis of the catch curve using the Fisat program, these losses concerned the size range of scallops over 60 mm in length with a mortality Z = 2.15 in 2002 for individuals ranging from 67.5 to 115.5 mm in length and Z = 3.08 in 2003 for those ranging from 64.3 to 112.5 mm. The results suggest that the loss of scallops from these size ranges was due to human intervention (clandestine harvesting), also reported by wardens in the field. Illegal harvesting of this resource contravenes Chilean national legislation designed to conserve A. purpuratus and maintain its rational exploitation. 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. La abundancia de ejemplares también mostró variabilidad interanual, con cifras de 10.1 × 106 en 2001, 8.2 × 106 en 2002 y 12.4 × 106 en 2003. Estas evaluaciones mostraron, además, una disminución en la talla media de la estructura demográfica del banco entre un año y otro, reduciéndose de 75.8 mm en 2001 a 62.1 mm en 2002 y a 51.7 mm en 2003. Esta disminución también ocurrió con el número de ejemplares mayores o iguales a la talla mínima legal (90 mm), reduciéndose de 2.6 × 106 ejemplares presentes en 2001 a 3.7 × 105 ejemplares en 2003. La aplicación de los parámetros de crecimiento sobre la estructura poblacional del banco entre 2002 y 2003 señaló la integración de una nueva clase anual de 6.5 × 106 de ejemplares en 2002 y de 11.2 × 106 de individuos en 2003. El descuento de estas cifras, del número total de ejemplares presentes en ambos años, demuestra una pérdida cercana a los 8.4 × 106 de ostiones en 2002 y de cerca de 7.0 × 106 de individuos en 2003. Estas pérdidas correspondieron a ejemplares con tallas superiores a los 60 mm, lo cual es corroborado con el análisis de la curva de captura realizado con el programa Fisat, cuyos resultados señalan una mortalidad Z = 2.15 en 2002 para el segmento de la población entre 67.5 y 115.5 mm, y Z = 3.08 en 2003 para el segmento de 64.3 a 112.5 mm. Los resultados sugieren que las pérdidas de ejemplares fueron producidas por la pesca clandestina, actividad que contraviene la legislación chilena diseñada para conservar a A. purpuratus y sostener una explotación racional de este recurso. Iniversidad Autónoma de Baja California 2005-03-06 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article Artículo Arbitrado application/pdf https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/46 10.7773/cm.v31i3.46 Ciencias Marinas; Vol. 31 No. 3 (2005); 491-503 Ciencias Marinas; Vol. 31 Núm. 3 (2005); 491-503 2395-9053 0185-3880 eng https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/46/28

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