Ontogenetic shift in the diet of Dajaus monticola (Mugiliformes: Mugilidae) with comments in the recruitment of young individuals in the Honduran Caribbean coast

ABSTRACT

Studies have been devoted to describing the diet of D. monticola. However, knowledge of how D. monticola utilizes food resources through ontogeny remains unknown. We characterized D. monticola general dietary patterns and tested for ontogenetic diet shifts. We also inferred on juvenile recruitment patterns. We examined the stomach contents of 120 specimens ranging in size from 20 to 154 mm in standard length (SL). To infer on recruitment periodicity, we examined the size of specimens deposited in museum collections to compile size frequencies by month. We assume that the occurrence of smaller-size class categories will shed light on their recruitment time. Our results show that D. monticola is an omnivore that largely feeds on aquatic insects but also includes detritus, terrestrial material, fishes and crustaceans. Our analysis did not detect strong changes in diet through ontogeny, instead some changes were detected but mainly on the percentage of some food items included at different size category classes. In regards to the recruitment periodicity, we found younger D. monticola (20–40 mm SL) throughout most of the year, suggesting that they may be reproducing for longer periods of time than those previously reported from Honduras.

Resumen

Varios estudios se han dedicado a describir la dieta de D. monticola. Sin embargo, el conocimiento de cómo D. monticola utiliza los recursos alimenticios a través de la ontogenia sigue siendo desconocido. Caracterizamos los patrones generales de la dieta de D. montícola. Tambien estudiamos los cambios ontogenéticos en dieta e inferimos sobre los patrones de reclutamiento de juveniles. Con el fin de comprender los cambios ontogenéticos en la dieta, examinamos el contenido estómacal de 120 especímenes que varían en tamaño de 20 a 154 mm en longitud patrón (SL). Para inferir sobre la periodicidad de reclutamiento, examinamos el tamaño de los especímenes depositados en las colecciones de los museos para recopilar las frecuencias de tamaño por mes. Suponemos que la aparición de categorías de clase de menor tamaño arrojará luz sobre su tiempo de reproducción. Nuestros resultados muestran que D. monticola es un omnívoro que se alimenta en gran medida de insectos acuáticos, pero también incluye detritus, material terrestre, peces y crustáceos. No detectamos cambios fuertes en la dieta a través de la ontogenia, sino que se detectaron algunos cambios, pero principalmente en el porcentaje de algunos alimentos incluidos en diferentes categorías de tamaño. Con respecto a la periodicidad de reclutamiento, encontramos D. monticola juveniles (20 - 40 mm SL) durante la mayor parte del año, lo que sugiere que pueden estar reproduciéndose por períodos de tiempo más largos que los reportados previamente en Honduras.

KEYWORDS:

• NMDS
• species indicator analysis
• mullet
• generalist feeder
• diet shifts

Acknowledgments

We are grateful to two anonymous reviewers for providing helpful comments on an earlier draft of this manuscript. We thank the Honduran Instituto de Conservacion Forestal for issuing collection permits to WAM. In addition we thank the staff at University of Michigan Museum of Zoology (UMMZ), The Florida Museum of Natural History (UF), the Los Angeles County Museum of Natural History (LACM) and the United States National Museum (USNM) for loaning specimens. Collection trips to Honduras were possible for a World Wildlife Fund (WWF) and United States Agency for International Development (USAID) grants to WAM. Additional funding was provided by a Critical Environment Partnership Fund.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Collection trips to Honduras were possible for a World Wildlife Fund (WWF) and United States Agency for International Development (USAID) grants to WAM. Additional funding was provided by a Critical Ecosystem Partnership Fund.