Dietary habits of juveniles of the Mayan cichlid, Cichlasoma urophthalmus, in mangrove ponds of an offshore islet in Belize, Central America

Abstract

Foraging habitats of juveniles of the Mayan cichlid, Cichlasoma urophthalmus (Günther, 1862), were investigated in two mangrove ponds located in Twin Cays offshore islet in Belize: Sink Hole pond (SH) and Hidden Lake pond (HL). Sink Hole pond is a semiclosed body of water, whereas Hidden Lake pond is connected by a channel to adjacent seagrass beds that surround the islet. Gut contents of 21 juvenile C. urophthalmus (9.8-13.2 cm total length) were analyzed, and five prey taxa were identified. In both mangrove ponds, C. urophthalmus were opportunistic carnivores and consumed primarily crustaceans. Plant material and detritus present in gut contents were most likely ingested incidentally when the fish foraged on small invertebrates. Carbon isotopic values of fish specimens from the two ponds were similar (mean ± SD of -19.2 ± 0.4‰ in SH and -19.4 ± 0.4‰ in HL), and were close to those of mangrove prey (mean ± SD = -20.2 ± 1.5‰), suggesting that this fish species forages in this habitat. Mixing models showed a higher contribution of mangrove food sources to the fish diet than seagrass food sources. This study reveals that young Mayan cichlids, inhabiting two Belize mangrove ponds, are generalists and opportunistic carnivores that forage on mangrove food sources and do not appear to move to adjacent seagrass beds to complement their diets. Understanding trophic linkages between aquatic consumers and food resources may contribute to better management of threatened coastal ecosystems.Habitats de alimentação de juvenis do ciclídeo-maia, Cichlasoma urophthalmus (Günther, 1862), foram investigados em duas lagoas de mangue localizadas nas ilhas Twin Cays em alto mar em Belize: Sink Hole Lake (SH) e Hidden Lake (HL). Sink Hole é um corpo d'água parcialmente isolado, enquanto Hidden Lake é ligada por um canal com bancos de sargaços que cercam a ilhota. O conteúdo estomacal de 21 juvenil de C. urophthalmus (9,8-13,2 cm de comprimento total) foram analisados e cinco táxons de presas foram identificados. Em ambas as lagoas de mangue, 'C.' urophthalmus foram carnívoros oportunistas e consumiram principalmente crustáceos. Material vegetal e detritos presentes no conteúdo digestivo foram provavelmente ingeridos acidentalmente quando o peixe se alimentava de pequenos invertebrados. Os valores de isótopos estáveis do carbono em espécimes de peixes das duas lagoas foram semelhantes (média ± SD -19,2 ± 0,4 ‰ em SH e -19,4 ± 0,4 ‰ em HL), e foram próximos aos de presas de mangue (mean ± SD = -20.2 ± 1.5 ‰), sugerindo que esta espécie de peixe vai à procura de alimentos neste habitat. Modelos mistos mostraram uma maior contribuição de fontes alimentares de mangue para a dieta dos peixes do que de fontes alimentares de algas marinhas. Este estudo revela que juvenis do ciclídeo-maia que habitam duas lagoas de mangue em Belize, são carnívoros generalistas e oportunistas que se ingerem alimentos dos manguezais e não parecem se mover para leitos de algas marinhas adjacentes para complementar suas dietas. Compreender as ligações tróficas ent...

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