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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. ...

Coastal zones support fisheries that provide food for humans and feed for animals. The decline of fisheries worldwide has fostered the development of aquaculture. Recent research has shown that extracellular polymeric substances (EPS) synthesized by microorganisms contribute to sustainable aquaculture production, providing feed to the cultured species, removing waste and contributing to the hygiene of closed systems. As ubiquitous components of coastal microbial habitats at the air-seawater and seawater-sediment interfaces as well as of biofilms and microbial aggregates, EPS mediate deleterious processes that affect the performance and productivity of aquaculture facilities, including biofouling of marine cages, bioaccumulation and transport of pollutants. These biomolecules may also contribute to the persistence of harmful algal blooms (HABs) and their impact on cultured species. EPS may also exert a positive influence on aquaculture activity by enhancing the settling of aquaculturally valuable larvae and treating wastes in bioflocculation processes. EPS display properties that may have biotechnological applications in the aquaculture industry as antiviral agents and immunostimulants and as a novel source of antifouling bioproducts.

The present study reports the seasonal dynamics of the fish community structure in the presence of a non-native fish (Pterygoplichthys pardalis) in tropical waterbodies of southern Mexico. The studied floodplain existed in both connected pools and disconnected pools “to the Palizada river”. Local fish fauna showed consistent assemblages across seasons, but among the 17 local fish species recorded, the non-native species P. pardalis showed the highest percentage of contribution to the fish community (ca. 20%). Conversely, the frequency of occurrence and density of the non-native species showed variation in relation to the type of waterbody and seasonality; its density was approximately four times higher in disconnected pools than in connected pools in the rainy season and its predominant size class in both pool types was 21-30 cm in standard length. Interestingly, the diversity of the native species was negatively related to the density of the non-native species, indicating that the presence of P. pardalis can be a factor involved in the decline of native fish diversity in these local communities. Currently, the possible impacts of the presence of P. pardalis on local fish diversity at the regional scale are unknown, but our results suggest that hydrological dynamics regulate the establishment of the non-native species in this region. However, future studies are needed to provide insights into the actual scenario of P. pardalis distribution in Yucatan Peninsula and the possible impacts on the native fish fauna in southern Mexico.