Spatial and temporal distribution of sea turtles related to sea surface temperature and chlorophyll-a in Mexican Central Pacific waters

Abstract

espanolEn este estudio se describe la distribucion espacio-temporal de tortugas marinas y su relacion con parametros oceanograficos en el Pacifico Central Mexicano (PCM) durante el 2010 (invierno, primavera y otono). Los resultados muestran variaciones en la distribucion de tortugas marinas. En invierno, la distribucion de tortugas fue homogenea en areas costeras y oceanicas; asociadas a la presencia de frentes termicos debido a la interaccion de una corriente de agua calida del sur y la intrusion de agua fria proveniente del noroeste, asi como con los limites de un giro ciclonico. En primavera, la distribucion de tortugas se concentro hacia la zona costera y parte central de la zona oceanica, donde prevalecieron los efectos de una surgencia y los limites de un giro ciclonico. El mismo patron de distribucion ocurrio al inicio de otono, mientras que las condiciones oceanograficas cambiaron para la segunda semana de muestreo, cuando ocurrio la formacion de una surgencia costera. Los eventos de apareamiento solo se registraron durante otono para la tortuga golfina (Lepidochelys olivacea), la especie dominante de la region. Se concluye que en otono el patron de distribucion de tortugas marinas fue hacia la zona costera del PCM, y se relaciono con actividades de reproduccion; mientras que en invierno y primavera este patron tendio a la region central/oceanica vinculado potencialmente con actividades de forrajeo. EnglishIn this study we describe the spatial and temporal distribution of sea turtles and their association with oceanographic parameters in waters of the Mexican Central Pacific (MCP) during 2010 (winter, spring and autumn). Our results showed variations in sea turtle distribution through the sampling year. Sea turtle distribution was homogeneous in coastal and oceanic areas during winter; there was an association with thermal fronts generated by a current of cold water flowing from the northwest and a warm current coming from the south, as well as with the boundaries of a cyclonic gyre. Sea turtles were distributed in the coastal zone and the central part of the oceanic zone in spring, where the effects of a cyclonic gyre and coastal upwelling prevailed. The same distribution trend was recorded at the beginning of autumn, whereas oceanographic characteristics changed during the second sampling week, when upwelling occurred. Mating events were only recorded in autumn for olive ridley sea turtles (Lepidochelys olivacea), the dominant species in the region. It was concluded that sea turtles were distributed in the coastal zone of MCP waters in autumn due to reproductive activities, whereas in winter and spring sea turtles were distributed towards the central/oceanic region, potentially related to foraging activities.