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About the Authors:
Paola A. Mejía-Falla
* E-mail: [email protected]
Affiliations Fundación Colombiana para la Investigación y Conservación de Tiburones y Rayas, SQUALUS, Carrera 60A No 11-39, Cali, Colombia, Grupo de Investigación en Ecología de Arrecifes Coralinos, Departamento de Biología, Universidad del Valle. A.A. 25360, Cali, Colombia
Enric Cortés
Affiliation: NOAA/National Marine Fisheries Service, Panama City, Florida, United States of America
Andrés F. Navia
Affiliation: Fundación Colombiana para la Investigación y Conservación de Tiburones y Rayas, SQUALUS, Carrera 60A No 11-39, Cali, Colombia
Fernando A. Zapata
Affiliation: Grupo de Investigación en Ecología de Arrecifes Coralinos, Departamento de Biología, Universidad del Valle. A.A. 25360, Cali, Colombia
Introduction
Knowledge of age and growth characteristics allows construction of age-based population models and, together with the consideration of other life history aspects and removal rates by fisheries, can eventually lead to an assessment of the population status of a given species [1]. While target species have often been intensely studied, bycatch species are often ignored. These commercially unimportant species, such as the stingrays in the Family Urotrygonidae, are also impacted by fisheries and information on their life history is needed as input to formulate fisheries management decisions.
The round stingray Urotrygon rogersi (Jordan and Starks 1895) is an endemic batoid of the Eastern Tropical Pacific Ocean that occurs on soft bottoms in coastal and shallow zones at depths of 2 to 30 m [2]. It is the most abundant elasmobranch species in the bycatch of artisanal and industrial prawn trawl fisheries on the Colombian Pacific coast and does not have any commercial value [3].
This species is a specialist that feeds mainly on crustaceans and polychaetes, showing a strong diet overlap between sexes and size classes [4]. This aplacental viviparous species attains a maximum size of 20 cm disc width (DW), its median size at maturity is 11.5–11.8 cm DW in males and 11.8–12.3 cm DW in females, size at birth is 7.5–8.2 cm DW and 11.5–14.7 cm total length, gestation lasts about 5–6 months, and the reproductive cycle is triannual and aseasonal [5].
Seasonally reproducing species usually have relatively well-defined birth dates [6] and therefore the age of individuals can be determined with reasonable accuracy [7]. In contrast, non-seasonally reproducing species can have several reproductive peaks or reproduce throughout...