Hábitos alimenticios en juveniles de Sphyrna Zygaena Linnaeus 1758 (Chondrichthyes: Sphyrnidae) en el puerto pesquero de Santa Rosa de Salinas, Guayas durante mayo – diciembre 2004
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2006
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Durante el periodo de mayo a Diciembre del 2004 se realizó el estudio acerca de
los hábitos alimenticios de los juveniles del tiburón martillo Sphyrna zygaena en el
puerto pesquero Santa Rosa del cantón Salinas; capturados con redes de enmalle
por la flota pesquera artesanal ecuatoriana. Se obtuvo información de 206 tiburones con la finalidad de conocer las especies presas que componen su dieta de acuerdo al estado de digestión de las presas, cantidad e importancia de cada una de ellas por medio del índice de importancia relativa (IIR). Se contabilizaron un total de 1921 presas, correspondiendo a 48 ítem presas; pertenecientes a 27 familias, 36 especies, 9 ítems presas se identificaron hasta el taxón Familia. Representando una diversidad moderada de acuerdo al índice de Shannon-Weaver y la equidad de Pielou. También se realizó el análisis de acuerdo a cinco intervalos de tallas y a meses de muestreo. Aplicando el índice de Morisita-Horn según N,% IIR, % F, %N y % W; entre machos y hembras se obtuvo valores superior a 0.6, lo que indica que no existe diferencia en la alimentación y entre las tallas existe un traslapo significativo en los intervalos de talla II-III (de 0.71 a 0.89) y III-IV (de 0.63 a 0.90). La amplitud de la dieta, determinada con el índice de Levin es baja (0.06), lo que indica que los juveniles de la especie S. zygaena se consideran depredadores especialistas por usar presas específicas para su consumo. Hábitos alimenticios en juveniles de Sphyrna zygaena Bolaño, N. 2006
From May to December of 2004 the study on feeding habits of juveniles of hammerhead shark Sphyrna zygaena in the fishing port Santa Rosa of the canton Salinas was done. The sharks were caught with nets from the Ecuadorian artisanal fishing fleet. A number of 206 sharks was obtained to know the prey species that compose their diet, based on digestion state of prey, quantity and importance of each one by means of the index of relative importance (IIR). A total of 1921 prey were recorded, corresponding to 48 items; belonging to 27families, 36 species, 9 items were identified until the taxon Family. Representando una diversidad moderada de acuerdo al índice de Shannon-Weaver y la equidad de Pielou. Also an analysis according to five ranges of sizes and months were done. By means of Morisita-Horn Index were got values between males and females higher than 0,6 which indicate that do not exist differences in the food, but between sizes exists a significant overlaping in the ranges of size IIIII (from 0.71 to 0.89) and III-IV (from 0.63 to 0.90). The niche trophic based on index of Levin it is low (0.06), which indicates that juvenile of S. zygaena is considered a specialist predator which use only some prey as main food.
From May to December of 2004 the study on feeding habits of juveniles of hammerhead shark Sphyrna zygaena in the fishing port Santa Rosa of the canton Salinas was done. The sharks were caught with nets from the Ecuadorian artisanal fishing fleet. A number of 206 sharks was obtained to know the prey species that compose their diet, based on digestion state of prey, quantity and importance of each one by means of the index of relative importance (IIR). A total of 1921 prey were recorded, corresponding to 48 items; belonging to 27families, 36 species, 9 items were identified until the taxon Family. Representando una diversidad moderada de acuerdo al índice de Shannon-Weaver y la equidad de Pielou. Also an analysis according to five ranges of sizes and months were done. By means of Morisita-Horn Index were got values between males and females higher than 0,6 which indicate that do not exist differences in the food, but between sizes exists a significant overlaping in the ranges of size IIIII (from 0.71 to 0.89) and III-IV (from 0.63 to 0.90). The niche trophic based on index of Levin it is low (0.06), which indicates that juvenile of S. zygaena is considered a specialist predator which use only some prey as main food.
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CONDRICTIOS, HÁBITOS ALIMENTICIOS, ÍNDICE, MUESTREO, TALLA, TIBURÓN MARTILLO