Fish diet composition in permanent and semi-permanent pools in tropical wetlands of the Yucatan Peninsula

Abstract

We compared fish diet composition between permanent (P) and semi-permanent (SP) pools in Petenes Biosphere Reserve (PBR), Campeche. A total of 445 gut contents were examined to determine stomach relative fullness (RF), fish diet as index of niche breadth (INB) and diet overlap. In SP pools, species showed a RF of 1.66 (57.20 % empty stomachs) whereas in P pools, the RF was 2.91 (31.16%). We classified fish diet into six trophic groups: detritivorous, herbivorousdetritivorous, insectivorous, piscivorous, omnivorous and malacophagous. Species in P pools were found to be specialist. Conversely, species present in both habitats shifted to generalist patterns. There was a 54.0% dissimilarity in fish diet composition between pools. From all items identified, detritus (21.33% of the total dissimilarity), aquatic and terrestrial invertebrates (12.31%), fish remains (10.29%), plant remains (7.37%), and crustaceans (2.74%) distinguished diets between pools. Significant diet overlaps (>0.6) and low INB values (<0.3) were observed in P pools, whereas in SP pools, intermediate-low diet overlaps (<0.4) and higher INB values (>0.5) were observed. In SP pools seasonality had a strong effect on fish diet, increasing the frequency of food items such as terrestrial insects, amphipods and arachnids, during the rainy season while P pools showed lower variation. Thus, fish trophic habits appear to be regulated by pools hydrology.Se analizaron y compararon los contenidos estomacales de la ictiofauna en cuerpos de agua permanentes (P) y semipermanente (SP) de la reserva de la Biosfera Los Petenes, Campeche. Se analizaron un total de 445 estómagos en los cuales se determino la diversidad de dieta (como Índice de amplitud de nicho = INB), plenitud relativa de estómagos (PRE) y traslape de dietas. En las pozas SP 57.20 % de los estómagos se encontraron vacíos y los estómagos con alimento presentaron un PRE de 1.66. En las pozas P solo el 31.16 % de los estómagos se encontraron vacíos y un PRE de 2.91. Los peces se clasificaron en seis grupos tróficos: detritívoros, herbívoros-detritívoros, insectívoros, piscívoros, omnívoros y malacófagos. Los individuos en la pozas P tendieron a presentar dietas especializadas mientras que en las pozas SP patrones generalistas. Se observo una disimilitud de dietas entre pozas del 54.0 % asociada a los items: detritus (21.33%), invertebrados acuáticos y terrestres (12.31%), fragmentos de peces (10.29%), fragmentos de vegetación (7.37%) y crustáceos (2.74%). Los mayores traslapes de dietas (> 0.6) y menores INB (< 0.3) se observaron en especies presentes en las pozas P mientras que en las pozas SP se observaron valores de traslape intermedios-bajos (<0.4) e INB mayores (> 0.5) en especies que utilizaron mayores fuentes de alimento. En las pozas SP la estacionalidad tuvo una marcada influencia en la proporción de los ítems: insectos acuáticos, anfípodos y arácnidos, los cuales presentaron mayores frecuencias, sobre todo en la época de lluvias, mientras que las pozas P no presentaron cambios significativos. ...

Fish functional groups in a tropical wetland of the Yucatan Peninsula, Mexico

“…Functional characterization was performed on a maximum of 15 adult individuals randomly selected from each species (Table 1). In the laboratory, fish were anesthetized with benzocaine (250 mg/L) before they were euthanized by overdose (Hinojosa-Garro et al, 2013). Immediately, mouth traits were measured and high-quality photographs were taken.…”

“…Therefore, it is necessary to seek further support for the functional groups based on additional biological information (Dumay et al, 2004). Here, we contrasted functional groups with published gut contents data (Soto-Galera, 2006;Miller, 2009;SchmitterSoto et al, 2011;Hinojosa-Garro et al, 2013) to determine trophic groups (Table 1).…”

Trophic strategy of Atlantirivulus riograndensis (Cyprinodontiformes: Rivulidae), a non-annual rivulid threatened by extinction, in a perennial environment, Brazil)

“…Fish with specialist tendencies associated with more stable habitats in regards to water variation (Poff & Allan, 1995;Hinojosa-Garro et al, 2013) are more easily detected when the food source is abundant compared to generalist fish associated with scarce food resources (Gerking, 1994).…”

“…Alternatively, the environment can dry up completely during the period of low rainfall, creating seasonal habitats (Lake, 2003;Mas-Martí et al, 2010;Hinojosa-Garro et al, 2013). The hydroperiod restrict the spatial distribution of ichthyofauna when the water levels fall or determine the existence of a community composed of species with the ability to sustain viable populations even in seasonal habitats (DeAngelis et al, 2010).…”

“…Specialist trends in stream fish were observed in stable hydrological systems in Wisconsin and Minnesota (in the United States), while in hydrologically variable stream ecosystems species appear to be more tolerant and to have increased trophic and habitat generalism (Poff & Allan, 1995). Likewise, a generalist feeding behavior has been identified in fish from seasonal pools in the Yucatan Peninsula, Mexico, contrasting specialist diets in populations of perennial habitats (Hinojosa-Garro et al, 2013).…”