Caracterización morfométrica de pangora (Menippe frontalis) en Posorja, Guayas, Ecuador
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2019
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Facultad de Ciencias Naturales. Universidad de Guayaquil
Resumen
Se estudió un total de 227 individuos de Mennipe frontalis obtenidos de la pesca artesanal de Posorja (Guayas, Ecuador) durante marzo – julio del 2018. Los especímenes fueron separados por sexo, pesados y se tomaron medidas del cefalotórax y quelas con el objetivo de determinar cambios de fases ontogénicas con base a sus variables morfométricas. La proporción sexual fue de 1:1.2, lo cual corresponde a 45% de machos y 55% de hembras. El rango de tallas observado para el ancho del cefalotórax fue de 50.65 mm a 144.80 mm. Los valores obtenidos de las mediciones de cefalotórax y quelas fueron representados mediante regresiones lineales. La relación ancho vs. largo del cefalotórax mostró una clara separación de dos grupos, que corresponde a dos períodos diferenciados de crecimiento y que fueron estadísticamente validados a través de la propuesta de Drape y Smith. Las relaciones morfométricas fueron sometidas a cinco modelos estadísticos candidatos (lineal, cuadrático, cúbico, punto de inflexión y dos segmentos) y el mejor modelo fue elegido mediante el criterio de selección de Akaike corregido (AIC) y el Bayesiano (BIC). El modelo lineal representó un mejor ajuste en la mayoría de las relaciones morfométricas y la relación tamaño-peso mostró una tendencia positiva. Adicionalmente, el análisis de covarianza mostró diferencias significativas (p < 0.001) en el crecimiento de hembras y machos.
A total of 227 individuals of Mennipe frontalis obtained from artisanal fishery in Posorja (Guayas, Ecuador) were studied during March - July of 2018. The specimens were separated by sex, weighed and measurements of cephalothorax and chelas were taken in order to determine changes in ontogenic phases based on their morphometric variables. The sex ratio was 1: 1.2, corresponding to 45% of males and 55% of females. The cephalothorax width size ranged from 50.65 mm to 144.80 mm. The values obtained from the measurements of cephalothorax and chelas were represented by linear regressions. The relation between cephalotorax width and length showed a clear separation of two groups, corresponding to two different periods of growth, which were statistically validated through Drape and Smith´s proposal. The morphometric relations were subjected to five candidate statistical models (linear, quadratic, cubic, inflection point and two segments) and the best model was selected by Akaike corrected criteria (AIC) and Bayesian (BIC). The linear model represented a better fit for most of the morphometric relations and the relation size-weight showed a positive trend. Additionally, the covariance analysis showed no significant differences (p < 0.001) in the growth of females and males.
A total of 227 individuals of Mennipe frontalis obtained from artisanal fishery in Posorja (Guayas, Ecuador) were studied during March - July of 2018. The specimens were separated by sex, weighed and measurements of cephalothorax and chelas were taken in order to determine changes in ontogenic phases based on their morphometric variables. The sex ratio was 1: 1.2, corresponding to 45% of males and 55% of females. The cephalothorax width size ranged from 50.65 mm to 144.80 mm. The values obtained from the measurements of cephalothorax and chelas were represented by linear regressions. The relation between cephalotorax width and length showed a clear separation of two groups, corresponding to two different periods of growth, which were statistically validated through Drape and Smith´s proposal. The morphometric relations were subjected to five candidate statistical models (linear, quadratic, cubic, inflection point and two segments) and the best model was selected by Akaike corrected criteria (AIC) and Bayesian (BIC). The linear model represented a better fit for most of the morphometric relations and the relation size-weight showed a positive trend. Additionally, the covariance analysis showed no significant differences (p < 0.001) in the growth of females and males.
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ALOMETRÍA, CANGREJO DE ROCA, CRECIMIENTO RELATIVO, RELACIONES MORFOMÉTRICAS