Hábitos de alimentación de peces arrecifales asociados con manglares y pastos marinos en una laguna del Caribe: Un enfoque de isótopos estables

Mangroves and seagrass beds represent suitable fish habitats as nurseries or feeding areas. This study was conducted in a Caribbean lagoon to assess the foraging habits of juvenile transient reef fishes in these two habitats. Twelve fish species were sampled in coastal mangroves, an offshore mangrove islet, and a seagrass bed site, and stable isotope analyses were performed on fishes and their prey items. The SIAR mixing model indicated that transient fishes from both mangroves and seagrass beds derived most of their food from seagrass beds and their associated epiphytic community. Only a few species including planktivores (Harengula clupeola, Anchoa lyolepis) and carnivores (Centropomus undecimalis and small specimens of Ocyurus chrysurus) presented depleted carbon values, showing reliance on mangrove prey in their diets. Mangrove-derived organic matter contributed marginally to the diet of transient fishes, which relied more on seagrass food sources. Thus, mangroves seem to function more as refuge than feeding habitats for juvenile transient fishes

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

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

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

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

Resource use by three juvenile scarids (Cryptotomus roseus, Scarus iseri, Sparisoma radians) in Caribbean seagrass beds

International audienceThe bucktooth parrotfish Sparisoma radians, the striped parrotfish Scarus iseri and the bluelip parrotfish Cryptotomus roseus are three herbivorous fishes commonly found at juvenile stages in Caribbean seagrass beds. While the diet of the three species as adults is relatively well known, few studies have been conducted on the feeding patterns of juveniles. In this study, the resource use of the juveniles of three scarid species were studied using two complementary methods: gut content and stable isotope analyses (13C:12C and 15N:14N ratios). Bayesian mixing model approaches were used to calculate the contribution of each food item to fish diets (SIAR, mixing models). The three parrotfish species appeared to rely essentially on the consumption of fleshy macrophytes. Cryptotomus roseus consumed more benthic invertebrates and presented a higher trophic level than the two other scarid species. Scarus iseri presented a higher assimilation of benthic biofilm, in accordance with the high percentage of sediment in its gut content, and Sparisoma radians assimilated more Thalassia testudinum leaves. This research highlighted a food resources partitioning among the juveniles of the three herbivorous fishes, probably to avoid inter-specific competitive interactions for the most palatable food at a critical stage of their life