| Autor: |
Torres-Huerta, A. M., Cruz-Acevedo, E., Carrasco-Bautista, P. E., Meraz-Hernando, J. F., Ramírez-Chávez, E. J., Tapia-García, M., Gracía, A. |
| Zdroj: |
Marine & Freshwater Research; 2020, Vol. 71 Issue 7, p844-854, 11p |
| Abstrakt: |
From January 2008 to December 2009, 451 specimens of witch guitarfish Zapteryx xyster were caught in the Gulf of Tehuantepec. Total weight, total length (TL), sex, maturity stage and catch depth were recorded for each specimen. Maturity stage distribution exhibited significant differences with respect to depth. The data indicated that adults migrated towards shallow waters (25–37 m) to reproduce, starting in February. Males reached maturity at 44 cm TL, whereas females reached maturity at 48 cm TL. Witch guitarfish females are synchronous; therefore, ovulation and mating begin in March and parturition begins in April. Females showed a 2-year cycle with consecutive vitellogenesis and gestation. Fecundity was five to eight embryos (mean six embryos) and the sex ratio of embryos was 1 : 1. Birth occurred in April and May, with an average size at parturition of 17.3 cm TL. There was sexual dichromatism between males and females during the breeding period, and sexual polymorphism in adult females. The incidental catch of the witch guitarfish during courtship and mating threatens the survival of this species. The witch guitarfish is caught incidentally in bottom trawl nets used in the shrimp fishery in the Gulf of Tehuantepec. Adults are probably concentrated at depths >60 m in the Gulf of Tehuantepec during most of the year and migrate towards shallow waters (from 25 to 37 m) to reproduce in February. The incidental catch of witch guitarfish during its reproductive cycle using bottom trawl nets could negatively affect the reproductive success and long-term viability of this species. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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