Aspectos de la biología reproductiva de la Corvina Aguada (Cynoscion squamipinnis) en el Golfo de Nicoya, Costa Rica
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Fecha
1999
Autores
Vásquez Arias, Ana Rita
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Editor
Universidad Nacional (Costa Rica)
Resumen
La corvina "aguada" Cynoscion squamipinnis es la especie íctica más importante de las explotadas en las aguas costeras del pacífico costarricense. De ahí que no sean pocos los estudios que, tanto en materia de pesquería como en biología básica, se han dirigido hacia esta corvina. El presente trabajo trató de la confección, para las hembras de C. squamipinnis, de una clave para la identificación clara de los estadios de madurez gonadal; características de gran relevancia a la hora de determinar aspectos tales como ciclos de reproducción, fecundidad y otros. Para esto se realizó el análisis gonadal tanto a escala macroscópica como microscópica. El análisis macroscópico tomó como principales características para definir el estado de madurez: el tamaño relativo de la gónada, su coloración, grado de irrigación y tamaño aparente de los oocitos. Así fue posible diferenciar claramente seis estadios de madurez: inactivo o inmaduro (individuos con gónadas muy pequeñas como filamentos, generalmente no es posible distinguir el sexo, talla menor a los 220 mm longitud total), madurando I (gónadas pequeñas pero se diferencia claramente el sexo, color rojizo traslucido); En desarrollo o En reposos (gónadas donde se aprecia mayor tamaño, coloración que evidencia el inicio de la vitelogénesis, pueden ser gónadas que se están recuperando de un previo desove o gónadas madurando por primera vez; los oocitos si se observan muy pequeños); Maduro o Desarrollado (la gónada se observa turgente, de color anaranjado, oocitos claramente distinguibles); Ovulación y Desove (estado difícil de encontrar por lo rápido que ocurre, caracterizado por la pérdida de coloración debido a los oocitos hidratados) y Reabsorción (la gónada se vuelve flácida, con mucho fluido, puede tomar un color violáceo). Para cada estado microscópico se realizó un análisis y descripción de la apariencia celular en los cortes microscópicos, donde se comprobó el carácter asincrónico de la vitelogénesis en esta especie. Por otro lado, la fecundidad absoluta de "aguada" vario entre 48.286 y 416.540 oocitos para hembras con tallas de 330 a 490 mm longitud total. La fecundidad relativa promedio (# de oocitos por gramo de hembra) fue de 139-467 y no presentó relación alguna con la talla. La longitud de primera madurez se estimó en [293-339] 95% de longitud total en mm.
The "aguada" croaker Cynoscion squamipinnis is the most important fish species exploited in the coastal waters of the Costa Rican Pacific. Hence, there are many studies that, both in terms of fisheries and basic biology, have been directed towards this croaker. The present work dealt with the creation, for C. squamipinnis females, of a key for the clear identification of the stages of gonadal maturity; characteristics of great relevance when determining aspects such as reproduction cycles, fertility and others. For this, the gonadal analysis was performed both on a macroscopic and microscopic scale. The macroscopic analysis took as main characteristics to define the state of maturity: the relative size of the gonad, its coloration, degree of irrigation and apparent size of the oocytes. Thus, it was possible to clearly differentiate six stages of maturity: inactive or immature (individuals with very small gonads such as filaments, it is generally not possible to distinguish the sex, size less than 220 mm total length), maturing I (small gonads but the sex, translucent reddish color); In development or At rest (gonads where larger size is appreciated, coloration that shows the beginning of vitellogenesis, may be gonads that are recovering from a previous spawning or gonads maturing for the first time; oocytes if they are observed very small); Mature or Developed (the gonad is turgid, orange, clearly distinguishable oocytes); Ovulation and Spawning (a state that is difficult to find because of how quickly it occurs, characterized by loss of color due to hydrated oocytes) and Reabsorption (the gonad becomes flaccid, with a lot of fluid, it can take on a purplish color). For each microscopic state, an analysis and description of the cellular appearance in the microscopic sections was carried out, where the asynchronous character of vitellogenesis in this species was verified. On the other hand, the absolute fecundity of "aguada" varied between 48,286 and 416,540 oocytes for females with sizes from 330 to 490 mm total length. The average relative fecundity (# of oocytes per gram of female) was 139-467 and did not show any relationship with height. The length at first maturity was estimated at [293-339] 95% of total length in mm.
The "aguada" croaker Cynoscion squamipinnis is the most important fish species exploited in the coastal waters of the Costa Rican Pacific. Hence, there are many studies that, both in terms of fisheries and basic biology, have been directed towards this croaker. The present work dealt with the creation, for C. squamipinnis females, of a key for the clear identification of the stages of gonadal maturity; characteristics of great relevance when determining aspects such as reproduction cycles, fertility and others. For this, the gonadal analysis was performed both on a macroscopic and microscopic scale. The macroscopic analysis took as main characteristics to define the state of maturity: the relative size of the gonad, its coloration, degree of irrigation and apparent size of the oocytes. Thus, it was possible to clearly differentiate six stages of maturity: inactive or immature (individuals with very small gonads such as filaments, it is generally not possible to distinguish the sex, size less than 220 mm total length), maturing I (small gonads but the sex, translucent reddish color); In development or At rest (gonads where larger size is appreciated, coloration that shows the beginning of vitellogenesis, may be gonads that are recovering from a previous spawning or gonads maturing for the first time; oocytes if they are observed very small); Mature or Developed (the gonad is turgid, orange, clearly distinguishable oocytes); Ovulation and Spawning (a state that is difficult to find because of how quickly it occurs, characterized by loss of color due to hydrated oocytes) and Reabsorption (the gonad becomes flaccid, with a lot of fluid, it can take on a purplish color). For each microscopic state, an analysis and description of the cellular appearance in the microscopic sections was carried out, where the asynchronous character of vitellogenesis in this species was verified. On the other hand, the absolute fecundity of "aguada" varied between 48,286 and 416,540 oocytes for females with sizes from 330 to 490 mm total length. The average relative fecundity (# of oocytes per gram of female) was 139-467 and did not show any relationship with height. The length at first maturity was estimated at [293-339] 95% of total length in mm.
Descripción
Vásquez Arias, A. (1999). Aspectos de la biología reproductiva de la Corvina Aguada (Cynoscion squamipinnis) en el Golfo de Nicoya, Costa Rica. [Tesis de Licenciatura]. Universidad Nacional, Costa Rica.
Palabras clave
CORVINA, ANIMALES ACUÁTICOS, AQUATIC ANIMALS, FERTILIDAD ANIMAL, ANIMAL FERTILITY, REPRODUCCION ANIMAL, CYNOSCION SQUAMIPINNIS, GOLFO DE NICOYA (COSTA RICA)