Alometría en Lithodes antarcticus Jacquinot, 1983 (Crustacea: decapoda): largo de la quela derecha versus largo del caparazón
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1987
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Se estudió la relación entre el largo de la quela derecha y el largo del caparazón en machos de Lithodes antarcticus Jacquinot 1853, de cinco áreas de pesca de la región de Magallanes (entre 50° y 54° 30' L.S.). Los especímenes fueron colectados hasta una profundidad aproximada de 60 m., entre septiembre-octubre de 1980 y enero-febrero de 1984. La información fue analizada mediante un análisis de regresiones y aplicando la ecuación alométrica de crecimiento linealizada. Se estudiaron separadamente los datos de juveniles (inmaduros) y adultos (maduros) . Debido a la variabilidad individual, existe un rango de tamaños en él que se traslapan ejemplares inmaduros y maduros. Los especímenes de este rango fueron clasificados según un criterio morfométrico utilizando una técnica similar a un análisis de conglomerados no jerárquico. En los juveniles, el crecimiento relativo entre ambas estructuras es isométrico y en los adultos, alométrico. Este patrón de crecimiento está asociado a la madurez sexual, siendo el incremento del largo de la quela alrededor de un 51% mayor durante la fase adulta. Los juveniles de las cinco áreas estudiadas, presentaron una tasa de crecimiento relativo homogénea. Un resultado similar se obtuvo con los adultos, por lo que se calculó una regresión común para cada fase de crecimiento. La diferencia entre los stocks estudiados, está en el tamaño al cual ocurre la ruptura de la línea de crecimiento. El rango de tamaños de este quiebre en cada sector está definido por las tallas del "maduro más pequeño" y el "inmaduro más grande". Existe un alto traslapo de este rango en casi todos los sectores estudiados, dificultando la identificación de los especímenes, si se usa el tamaño de la quela derecha para precisar el área de captura.
Son necesarios más estudios para comprender las variaciones geográficas de la morfometría y detectar rasgos evolutivos divergentes en el crecimiento relativo de los stocks de L. antarcticus, en la región de Magallanes.
Right chela length and carapace length relationship in males of Lithodes antarcticus Jacquinot 1853, from five fishing areas of the Magellan region (between 50º and 54º 30' S.L.) was studied. Specimens were collected approximately up to 60 m depth, between september-october 1980 and january-february 1984. Information was analyzed using a regression analysis applying the linearized allometric growth equation. Data from juveniles (inmatures) and adults (matures) were studied separately. Due to individual variability, there is a size range, where inmature and mature specimens overlap. Specimens from this range were classified according to a morphometric criterion, using a technique similar to a non hierarchical cluster analysis. Relative growth between both body structures is isometric in the juvenile phase, and allometric during the adult phase. This growth pattern is asseciated to sexual maturity, being the chela length increase about 15% higher during the adult phase. Juveniles from the five study areas showed a homogenous relative growth rate, and a similar result was obtained for adults. Thus, a common regression for each growth phase was calculated. Differences between studied stocks are in the sizes at which occur the rupture of growth line. The size range of this rupture in each sector is defined by the sizes of the "smallest mature specimen" and the "largest inmature specimen". There is a high overlap of this size range between study sectors, difficulting, specimens identification to precise capture area if right chela size is used. More studies are needed to comprise geographic morphometric variations and to detect evolutive divergence features in relative growth of L. antarcticus stocks in the Magellan region.
Right chela length and carapace length relationship in males of Lithodes antarcticus Jacquinot 1853, from five fishing areas of the Magellan region (between 50º and 54º 30' S.L.) was studied. Specimens were collected approximately up to 60 m depth, between september-october 1980 and january-february 1984. Information was analyzed using a regression analysis applying the linearized allometric growth equation. Data from juveniles (inmatures) and adults (matures) were studied separately. Due to individual variability, there is a size range, where inmature and mature specimens overlap. Specimens from this range were classified according to a morphometric criterion, using a technique similar to a non hierarchical cluster analysis. Relative growth between both body structures is isometric in the juvenile phase, and allometric during the adult phase. This growth pattern is asseciated to sexual maturity, being the chela length increase about 15% higher during the adult phase. Juveniles from the five study areas showed a homogenous relative growth rate, and a similar result was obtained for adults. Thus, a common regression for each growth phase was calculated. Differences between studied stocks are in the sizes at which occur the rupture of growth line. The size range of this rupture in each sector is defined by the sizes of the "smallest mature specimen" and the "largest inmature specimen". There is a high overlap of this size range between study sectors, difficulting, specimens identification to precise capture area if right chela size is used. More studies are needed to comprise geographic morphometric variations and to detect evolutive divergence features in relative growth of L. antarcticus stocks in the Magellan region.
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Centolla (Lithodes antárctica Jacquinot), Alometría
Citación
Anales del Instituto de la Patagonia, Vol. 17, pp. 89-98, 1987.