La pesquería de tiburones oceánicos-costeros en los litorales de Colima, Jalisco y Michoacán

Abstract

Fishery of oceanic and coastal sharks in Colima, Jalisco and Michoacán. Shark fishery is one of the most important activities in the Mexican Pacific coast, nevertheless, there is few data available about the specific captures done by the fleet along the coast. This study describes fishery biology aspects of the shark species catched by the semi-industrial long-line fleet of Manzanillo. Monthly samplings were made on board of these vessels during an annual period from April 2006 to April 2007. Captured species composition (n=1 962 organisms) was represented by nine species. The one that sustains this fishery was Carcharhinus falciformis (88.12%), followed by Prionace glauca (8.21%). Low frequency species were represented by Sphyrna zygaena (1.78%), Alopias pelagicus (0.82%), Carcharhinus longimanus (0.45%). Furthermore, rare species were Alopias superciliosus (0.35%), Carcharhinus leucas (0.1%), Carcharhinus limbatus (0.1%) and Isurus oxyrinchus (0.05%). Fishery activity affected principally (60-92.70%) young males of C. falciformis, S. zygaena, C. longimanus and I. oxyrinchus; adult males (56-75%) of A. pelagicus, A. superciliosus, and C. limbatus; for P. glauca there were primarily female adults. For all the species found, females showed the bigger sizes when compared to males (with the exception of S. zygaena, that showed sexual dimorphism). Considering the lineal regressions made between precaudal length and total length, and, fork length and total length for C. falciformis, P. glauca, S. zygaena and A. pelagicus, the determination coefficients (r 2 ) showed that both lengths can be useful to obtain the total length of fish with some damage or absence of its caudal fin. The estimated fecundity for C. falciformis was of 3-7 offspring/female of 30-45cm LT (average of 40.57+2.03cm LT); and for P. glauca 5-52offspring/female of 5-18.6cm LT (average of 11.61±0.21cm LT). In the case of C. longimanus only one female was captured with a total of eight embryos, with an average of 45cm LT each; for this reason we assumed that the fishery areas do not coincide with the nursery oness for this species. According to the information obtained, we concluded that C. falciformis has a concurrent cycle and P. glauca a consecutive biannual one. Rev. Biol. Trop. 59 (2): 655-667. Epub 2011 June 01.

Population structure and reproductive characteristics of the silky shark Carcharhinus falciformis (Müller & Henle, 1839) (Carcharhiniformes: Carcharhinidae) off the coast of Oaxaca, Mexico

“…En la costa de Oaxaca las hembras pueden contener al mismo tiempo ovocitos vitelogénicos, huevos o embriones, que junto con la distribución mensual de la talla de los embriones, sería indicativo que esta especie da a luz a lo largo del año o en la mayor parte del año. Esto se ha observado en otras regiones tropicales del Pacífico e Índico, donde no tiene un periodo de alumbramiento fijo (Strasburg, 1958;Bass et al, 1973;Stevens & McLoughlin, 1991;Cruz et al, 2011;Hoyos-Padilla et al, 2012). Sin embargo, en aguas templadas-cálidas del Golfo de México, Branstetter (1987) y Bonfil et al (1993 sugieren un periodo de gestación de 12 meses y fijan el período de nacimientos de mayo a junio.…”

“…Debido a su amplia distribución e importancia pesquera (Bonfil et al, 2009), se han realizado estudios sobre aspectos reproductivos de esta especie en diferentes partes del mundo (Branstetter, 1987;Last & Stevens, 1994;Oshitani et al, 2003;Joung et al, 2008;Hall et al, 2012). Sin embargo, son escasos los antecedentes en las costas Atlántica (Bonfil et al, 1993) y Pacífica de México (Soriano et al, 2006;Cruz et al, 2011;Hoyos-Padilla et al, 2012;Galván-Tirado et al, 2015).…”

Resilience of Sphyrna lewini, Rhizoprionodon longurio, and Carcharhinus falciformis at the entrance to the Gulf of California after three decades of exploitation

“…En el sur del Pacífico mexicano, esta especie es también un componente importante de los desembarques de la flota artesanal; por ejemplo, en Oaxaca, contribuyó con 64% de las Oaxaca it accounted for 36% of the shark landings during 2004-2005(n = 1187) (Alejo-Plata et al 2006. Additionally, it contributes significantly to the catches of the semi-industrial fleet operating in the central Mexican Pacific, representing 88% of the landings during 2006-2007 (n = 1962) (Cruz et al 2011) and 53% of the catches of longline vessels during 2003-2011 (Santana-Hernández and Flores-Valdez 2013). The analyzed species are widely distributed at the entrance to the GC (Compagno et al 1995) (fig.…”

“…En Chiapas representó 60% de la captura total de tiburón durante 1996-2003(Soriano-Velásquez et al 2006, y en Oaxaca representó 36% de los desembarques de tiburón durante 2004-2005(n = 1187) (Alejo-Plata et al 2006. Además, C. falciformis contribuye significativamente a las capturas de la flota semi-industrial que opera en el Pacífico central mexicano, representando el 88% de los desembarques durante 2006-2007 (n = 1962) (Cruz et al 2011) y el 53% de las capturas de la flota palangrera durante 2003-2011 (Santana-Hernández y Flores-Valdez 2013).…”

New report of malformations in blue shark embryos (Prionace glauca) from the western coast of Baja California Sur, Mexico

“…This fishery faces management problems with overfishing because catches are predominately immature sharks, motivating the need for further research (Sosa-Nishizaki et al , 2008). The catch size reported has been 77–274 cm TL (Cruz et al , 2011) while size at first maturity in females is 186–212 cm TL (Nakano & Seki, 2003). The blue shark is a viviparous species with a gestation period of 9–12 months and high fecundity (Pratt, 1993; Hazin et al , 2000).…”