Evaluación de algunos aspectos poblacionales de Centropomus unionensis Bocourt, 1868, en la parte interna del Golfo de Nicoya, Costa Rica
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2013
Autores
Zubiría Rengifo, William
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Universidad Nacional (Costa Rica)
Resumen
Desde enero de 2009 a diciembre de 2010, se estudiaron y examinaron en diferentes centros de acopio, puntos de venta y muelles de desembarco ubicados en la parte interna del Golfo de Nicoya, 734 ejemplares de róbalo "mano de piedra" Centropomus unionensis con una longitud total (Lt) entre 21,1 y 38 cm, una talla media de 29,1 cm (D.E=3,1) y un peso total entre 123,3 y los 511 gramos. Se determinaron aspectos como la relación longitud total-peso eviscerado (Lt vs Pe), crecimiento, proporción de sexos, y talla de primera madurez sexual.
La relación longitud total-peso eviscerado resultó ser igual a Pe = 2* 10-5 Lt 289 con un 0,8507; C. unionensis presentó una proporción de sexos de 2.3:1 (Hembras:Machos). Se observó la presencia de individuos en estados iniciales de maduración en todos los meses que la especie pudo ser monitoreada, pero el periodo reproductivo más importante se observó en los meses de marzo a mayo y, el segundo, en el mes de agosto, por tanto los mayores valores del índice gonadosomático (IGS) se presentaron en esos mismos meses.
La talla media de madurez (TMM) de las hembras estudiadas durante este periodo de estudio fue de 29,2 cm. La longitud asintótica obtenida mediante la ecuación de Von Bertalanffy fue de 41,5 cm, mostrando un crecimiento rápido en el primer año de vida. Las tasas de mortalidad obtenidas fueron: Natural (M=l ,83), por pesca (F= 2,87), Total (Z= 4,7) y el índice de explotación (E= 0,61). A pesar de que la especie no se encuentra sobreexplotada en el área de estudio, se recomienda regular su captura sobre todo en los meses de mayor actividad reproductiva.
From January 2009 to December 2010, 734 specimens of "stone hand" snook Centropomus unionensis with a length of total (Lt) between 21.1 and 38 cm, an average height of 29.1 cm (SD=3.1) and a total weight between 123.3 and 511 grams. Aspects such as the total length-gutted weight ratio (Lt vs Pe), growth, sex ratio, and size at first sexual maturity were determined. The relationship total length-gutted weight was equal to Pe = 2* 10-5 Lt 289 with 0.8507; C. unionensis presented a sex ratio of 2.3:1 (Female:Male). The presence of individuals in initial stages of maturation was observed in all the months that the species could be monitored, but the most important reproductive period was observed in the months of March to May and, the second, in the month of August, therefore the highest values of the gonadosomatic index (IGS) occurred in those same months. The mean size at maturity (TMM) of the females studied during this study period was 29.2 cm. The asymptotic length obtained using the Von Bertalanffy equation was 41.5 cm, showing rapid growth in the first year of life. The mortality rates obtained were: Natural (M=1.83), by fishing (F= 2.87), Total (Z= 4.7) and the exploitation index (E= 0.61). Despite the fact that the species is not overexploited in the study area, it is recommended to regulate its capture, especially in the months of greatest reproductive activity.
From January 2009 to December 2010, 734 specimens of "stone hand" snook Centropomus unionensis with a length of total (Lt) between 21.1 and 38 cm, an average height of 29.1 cm (SD=3.1) and a total weight between 123.3 and 511 grams. Aspects such as the total length-gutted weight ratio (Lt vs Pe), growth, sex ratio, and size at first sexual maturity were determined. The relationship total length-gutted weight was equal to Pe = 2* 10-5 Lt 289 with 0.8507; C. unionensis presented a sex ratio of 2.3:1 (Female:Male). The presence of individuals in initial stages of maturation was observed in all the months that the species could be monitored, but the most important reproductive period was observed in the months of March to May and, the second, in the month of August, therefore the highest values of the gonadosomatic index (IGS) occurred in those same months. The mean size at maturity (TMM) of the females studied during this study period was 29.2 cm. The asymptotic length obtained using the Von Bertalanffy equation was 41.5 cm, showing rapid growth in the first year of life. The mortality rates obtained were: Natural (M=1.83), by fishing (F= 2.87), Total (Z= 4.7) and the exploitation index (E= 0.61). Despite the fact that the species is not overexploited in the study area, it is recommended to regulate its capture, especially in the months of greatest reproductive activity.
Descripción
Zubiría Rengifo, W. (2013). Evaluación de algunos aspectos poblacionales de Centropomus unionensis Bocourt, 1868, en la parte interna del Golfo de Nicoya, Costa Rica. [Tesis de Maestría]. Universidad Nacional, Puntarenas, C.R.
Palabras clave
REPRODUCCION, REPRODUCTION, ESPECIES, PECES, FISH, AGUA DULCE, GOLFO DE NICOYA (COSTA RICA)