Feeding Ecology of the Blackwing Searobin Prionotus rubio (Jordan, 1886) Over the Western Continental Shelf off Alvarado, Veracruz, Mexico

Seasonal changes of food habits of the blackwing searobin Prionotus rubio were studied over the continental shelf off Alvarado, Veracruz, Mexico, from Sept. 1994 to Aug. 1995. A total of 234 stomachs (182 with identifiable food) were analyzed. Brown shrimp Farfantopenaeus aztecus, blue crab Portunus spinicarpus, and rock shrimp Sicyonia dorsalis were the main dietary items. Low values of prey diversity and dietary breadth suggest the main prey were always relatively abundant over the western continental shelf of the Gulf of Mexico. We concluded the blackwing searobin is part of a trophic guild of demersal marine fish that impact mainly on epibenthic invertebrates

Riqueza y abundancia relativa de los batoideos de la pesquería artesanal en el archipiélago Espíritu Santo, BCS, México

Background: The Gulf of California possesses a high diversity of marine ichthyofauna while representing one of the main fishing areas in Mexico. The shark and ray fishery constitute an important economic and social importance. Goals: In the present study, the richness and relative abundance was estimated (expressed as CPUE), for 15 batoids species taken by the artisanal fisheries in the southern zone of the Espiritu Santo Island, State of B.C.S. from October 2013 to December 2015. Methods: Batoids were taxonomically identified to species level, measured, sexed and weighed and species richness calculated. Catch as CPUE was standardized to 100 m of gillnet per hour (x100 as a scaling factor) and evaluated among species and at different spatial scales (season, year, season per year and month). Results: A total of 2198 individuals were captured and comprised of four orders, 10 families, 10 genera, and 15 species. The nominal capture effort used was 27560 m of bottom-set gillnet and 1763 h submerged time. Four species, Rostroraja velezi, Pseudobatos glaucostigma, Urobatis maculatus and Mobula mobular, were added to the existing ichthyofauna listing for the Espiritu Santo Island. Additionally, Mobula munkiana and Hypanus dipterurus represented the highest contribution in abundance and weight during the time of this study. The first species is currently protected by national and international laws, whereas the latter is a commercially exploited species. Conclusions: The partial overlap of the highest CPUE values recorded in the warm season, with the fishing ban and the reproductive activity of some species in summer, could contribute as a population recovery effect if the fishing effort after the ban is regulated.Antecedentes: El Golfo de California presenta una alta diversidad de organismos marinos y es una de las principales áreas de pesca en México. La pesquería de tiburones y rayas constituye una importante actividad económica con relevancia social. Objetivo: En el presente estudio se estima la riqueza y abundancia relativa (expresada como CPUE), de 15 especies de batoideos capturados por la pesca artesanal en la zona sur de la Isla Espíritu Santo, B.C.S. desde octubre del 2013 a diciembre de 2015. Métodos: Los ejemplares capturados fueron determinados taxonómicamente al nivel de especie, medidos, sexados y pesados. La riqueza específica correspondió al número total de especies capturadas durante el periodo de estudio. Los datos de CPUE fueron estandarizados a 100 metros de red por hora (x100 como factor de escalamiento) y evaluados entre especies y a diferentes escalas temporales (época, año, época por año y meses). Resultados: Se capturó un total de 2198 individuos, agrupados en cuatro órdenes, 10 familias, 10 géneros y 15 especies. El esfuerzo nominal empleado fue de 27560 metros de red y 1763 horas de remojo. Las especies Rostroraja velezi, Pseudobatos glaucostigma, Urobatis maculatus y Mobula mobular fueron adicionadas a los listados ictiofaunísticos existentes para la Isla Espíritu Santo. Mobula munkiana e Hypanus dipterurus, fueron las especies de batoideos con la mayor contribución en abundancia y peso durante el tiempo de la investigación. La primera está protegida por leyes nacionales e internacionales y la segunda es una especie aprovechada comercialmente. Conclusiones: La superposición parcial de los valores de CPUE más altos registrados en la época cálida, con la veda y la actividad reproductiva de algunas especies en verano, podría contribuir como un efecto de recuperación poblacional si se regula el esfuerzo pesquero posterior a la veda

Interdependencia ecotrófica entre Laguna de Alvarado, Veracruz y la plataforma continental adyacente

IMPRESO Y PD

Fish communities in high-latitude mangrove in north-western Mexico

Studying fish communities in extreme habitats is important to better understand the variation in their ranges under climatic scenarios or anthropogenic pressure. In particular, the mangroves in Baja California Sur occupy the northernmost distribution range under two extreme conditions (temperate waters and arid weather). In this context, the aim of the presently reported study was to analyze the functional characteristics of ichthyofauna in two localities, La Paz Bay (BP) and Almejas Bay (BA), which are also located in different ecoregions. For both bays, the composition and frequency values were compiled from monthly samples and the literature. Eleven functional traits were assessed from the morphology of every fish species. Functional indices (Richness, Evenness, Divergence, and Originality) were used to evaluate different aspects of the community structure. A total of 83 species were found at both sites, with 54 in BP and 50 in BA. In BP, six species were residents, eight were temporal visitors, and 36 were occasional visitors. In BA, six species were residents, 15 species were temporal visitors, and 33 were occasional visitors. At both sites, 12% of the species were permanent residents; BA had a higher percentage of temporal residents (27%), while BP had a higher percentage of occasional visitors (72%). The functional analysis detected communities with specialized traits, but in comparison to BP, BA had higher evenness in the community structure. Although greater structural complexity was expected in the community during the warm months, because of the increase in richness and attributes, BA had higher values during the cold months, which was probably because the area is a transition zone and the fish communities are adapted to colder climates. In comparison to BA, BP had higher originality values, and colder months presented higher values than warmer months. Although the mangrove sites had the same northernmost latitudinal limits and both had extreme conditions compared to those in mangroves in tropical environments, the fish communities differed in their composition, frequency, and functionality with more extreme functional traits in colder weather than in warmer weather

Importance of Weak Trophic Interactions in the Structure of the Food Web in La Paz Bay, Southern Gulf of California: A Topological Approach

Here, we describe the trophic structure of the La Paz Bay, Baja California Sur, Mexico, and evaluate the role of weak trophic interactions in the ecosystem using a suite of topological indices. We used information derived from published and unpublished stomach contents analysis studies from the region to construct an unweighted and directional trophic network (comprising 250 nodes and 1528 associated interactions) to assess the impact of predators in three scenarios. Each scenario simulated the removal of weak interactions corresponding to removal of those nodes with trophic contributions less than 5%, 10%, and 15%. In each removal scenario, the nodes phytoplankton and zooplankton exhibited the greatest betweenness and closeness centrality, suggesting that they are critical groups in the structure of the web, especially in the transference of indirect effects to the largest number of possible nodes in the network. The multiphyletic nature of the phytoplankton and zooplankton, and their ubiquity in diets served to increase their connectivity to all taxonomic groups. We note the presence of numerous weak interactions (67% of taxa have weak trophic interactions) and speculate that this characteristic confers ecological resilience in the Bay of La Paz coastal marine ecosystem

“Diabetes and Metabolism Disorders Medicinal Plants: A Glance at the Past and a Look to the Future 2018”: Antihyperglycemic Activity of Hamelia patens Jacq. Extracts

Diabetes is one the world’s most widespread diseases, affecting over 327 million people and causing about 300,000 deaths annually. Despite great advances in prevention and therapy, existing treatments for this disorder have serious side effects. Plants used in traditional medicine represent a valuable source in the search for new medicinal compounds. Hamelia patens Jacq. has been used for treating diabetes and, so far, no reports have been made on the in vivo antihyperglycemic activity of this plant. The present study on H. patens aimed to test the antihyperglycemic effect of repeated administrations of the crude and fractional methanolic extracts (CME and FME, respectively) on rats with hyperglycemia induced by streptozotocin. After 10 administrations (20 days), each extract had lowered blood glucose to a normal level. The extracts produced effects similar to metformin. Of the five compounds identified by chromatographic analysis of the extracts, epicatechin and chlorogenic acid demonstrated antihyperglycemic effect. The antioxidant activity of the extracts was evidenced by their IC50 values (51.7 and 50.7 μg/mL, respectively). The LD50≥2000 mg/Kg suggests low toxicity for both CME and FME. Thus, considering that the antihyperglycemic and antioxidant effects of metformin and extracts from H. patens were comparable, the latter may be efficacious for treating diabetes

Functional Diversity In Fish Assemblages of the Tropical Eastern Pacific Ocean: A Review of Two Decades of Progress In the Functional Diversity Approach

Background: One of the most relevant topics in ecology and evolution is understanding the relationship between biological and functional diversity at the ecosystem level; both important in the evolutionary processes and the structuring of complex communities. Goals: In this essay, the explanatory hypotheses focused on global patterns of the distribution of species are described along with selected hypotheses relating species richness/biodiversity to ecosystem function, and the differentiation of the terms guild and functional groupare discussed. Methods: Both biodiversity and functional diversity are key in the evolutionary processes and the structuring of complex communities and thus examples of functional equivalence of convergent evolution derivatives are presented in terms of the form and ecological habits of fishes of the Tropical Eastern Pacific Ocean. Finally, the importance of redundancy in ecosystem functioning is examined as well as the impact of environmental disturbances on ecosystem function. Results: In general, systems with low species richness and redundancy within functional groups are more vulnerable to disturbances. However, despite the extensive effort to understand the relationship between species richness/biodiversity and ecosystem functioning, there is no consensus on the effect of species loss on the functioning of the ecosystem. Some hypothesize that each species is unique and plays a unique role in the ecosystem whereas alternate hypotheses indicate that species overlap in function supporting sustainability at the ecosystem level, such that the removal of one species function may be replaced by another. Conclusions: The most widely accepted concept is that a greater number of species increases the efficiency in the use of resources and also provides resilience against environmental changes or impacts through functional redundancy