Trophic spectrum of the sailfishIstiophorus platypteruscaught off Acapulco in the southern Mexican Pacific

Abstract

The sailfish Istiophorus platypterus is one of the most common billfish species in the Mexican Pacific. Information about its feeding habits in the coastal region of Acapulco, Guerrero is extremely limited. In the present study we quantified the diet of sailfish, based on captures made from March 2008 to December 2009 by the sport fishing fleet of Acapulco. We analysed a total of 561 stomachs, of which 254 contained food (45%). The size interval of examined specimens was between 101 and 212 cm postorbital length and between 15 and 47 kg total weight. In general, teleosts were the most important prey, followed by cephalopods. According to index of relative importance, the most important species in the diet were the fish Auxis thazard (63.04%) and Fistularia commersonii (6.62%), followed by the cephalopod Octopus spp. (4.58%). There were no significant differences in the diet by sex (males and females), sexual maturity (immature and mature), or by season (warm and cold seasons). In all cases the most important prey species was A. thazard. We conclude that the sailfish I. platypterus off Acapulco behaves as a specialist predator because, despite the consumption of a high number of prey items, it feeds preferentially on a reduced number of prey species that form schools, and are available and abundant in the ocean.

Feeding habits of billfishes (Carangaria: Istiophoriformes) in the Ecuadorian Pacific Ocean

“…The diet of I. platypterus varied seasonally; this contrasts with the results reported for this species off Acapulco, Mexico, where no seasonal differences have been observed in diet (Hernández-Aguilar et al, 2013). This seasonal variation may be influenced by the coastal habitat of this species and the seasonal availability of different prey in the area.…”

“…has been reported as an abundant prey in the eastern Pacific Ocean (Olson, Boggs, 1986;Olson et al, 2014); the importance of Auxis spp. for billfishes previously was demonstrated off the coast of Cabo San Lucas, Mexico, for M. nigricans (Abitia-Cárdenas et al, 1999), and off Acapulco, Mexico, for I. platypterus (Hernández-Aguilar et al, 2013). Scombrid fishes, including Auxis thazard and Auxis rochei also have been reported as the most abundant prey group for I. platypterus, M. nigricans, and K. audax in the eastern North Pacific Ocean (Shimose et al, 2010).…”

“…The asymptote was not reached in any of the species accumulation curves despite the large sample size; a number of factors contributed to this, including differential digestion rates, regurgitation of the stomach contents as the result of being caught during fishing (Chase, 2002;Hernández-Aguilar et al, 2013), and the daily periodicity of feeding (Shimose et al, 2006). The low SCI values suggest that these billfishes do not feed actively before dawn or at night in this area.…”

Trophic interactions between five pelagic fish species cohabiting in the coast of Oaxaca, MexicoRelaciones tróficas entre cinco especies de peces pelágicos que cohabitan en las costas de Oaxaca, México

“…En estudios sobre hábitos alimentarios, donde conocer el espectro trófico de las especies presa es importante, es posible observar sesgos causado por la falta de representatividad en las muestras. En el presente estudio, el índice de vacuidad fue alto (69%), situación que al parecer es frecuente en este tipo de estudios, donde reportan niveles aproximados (Hernández-Aguilar et al, 2012;Varghese et al, 2014). De acuerdo a Olson y Boggs (1986), este tipo de especies presenta una alta tasa de evacuación, debido a sus altos requerimientos energéticos para nadar continuamente, mantener su equilibrio hidrostático y ventilar sus branquiespinas.…”

“…Los estudios sobre este tópico en pelágicos mayores son comunes, los cuales indican en general, que estos organismos se alimentan principalmente de cefalópodos, peces y crustáceos, aunque en diferentes proporciones (Olso & Galván-Magaña, 2002;Arizmendi-Rodríguez el al., 2006;Ravi & Sekar, 2010;Duffy et al, 2015). Las especies Coryphaena hippurus Linnaeus, 1758 y Carcharhinus falciformis (Bibron, 1839) se les considera oportunistas que se alimentan de una variedad de presas, pero que dependen de la disponibilidad y abundancia de las mismas (Olson & Galván-Magaña, 2002;Duffy et al, 2015), mientras que Istiophorus platypterus (Shaw, 1792) es más selectiva al consumir un mayor porcentaje de peces y cefalópodos (Arizmendi-Rodríguez et al, 2006;Ravi & Sekar, 2010;Hernández-Aguilar et al, 2012) y Thunnus albacares Bonnaterre, 1788, es considerada que posee un amplio intervalo de alimentación con altos requerimientos energéticos (Olson et al, 2014).…”