Spatial and temporal variation in diet composition of invertivore fishes in a tropical stream, Venezuela. Invertivores fishes are an important component of neotropical streams and they represent a link between aquatic invertebrates and piscivorous species. This study evaluated the breadth diet and interspecific food overlap of nine invertivores fish species during three consecutive hydrological phases: falling (December/07, January/08, February/08 and March/08), low (April/08) and rising waters (June/08), in two sections of a Venezuelan neotropical stream, which were located at different elevation, high watershed (HW) and low watershed (LW). The fishes were collected with a beach seine (5mm mesh) between 8:00 and 11:00 hours. The diet of each species was evaluated using an index of relative importance (IRI), which includes as variables the number, weight and occurrence frequency of food items consumed. The Levin' index (B i) and Morisita (IM) were used to estimate the breadth diet and interspecific food overlap, respectively. All estimations were made using the numeric proportion of preys. Nine fish species were captured, eight Characiformes, of which three were captured in HW (Knodus deuteronoides, Creagrutus bolivari and C. melasma) and five in LW (Thoracocharax stellatus, Moenkhausia lepidura, Cheirodon pulcher, Ctenobrycon spilurus and Aphyocharax alburnus), and one Cyprinodontiformes (Poecilia reticulata), which was also found in HW. In HW aquatic insects were the main resource consumed by fishes while plant material and terrestrial arthropods were secondary resources. In LW the fishes ingested all of these items in addition to zooplankton (Copepoda, Cladocera and larval stages of Decapoda). However, there was a temporal replacement with a predominance of zooplankton in falling and low water. In general, the breadth diet decreased during the falling water in both sections and increased in rising water. However, the average breadth diet was higher in HW. The interspecific food overlap was high in HW while low values were more frequent in LW and its temporal variation was opposed in both sections during almost all the sampling period.

No abstract

Trophic network of a fish community in a seagrass bed in the Venezuelan Caribbean. Seagrass beds are considered important feeding places for a variety of fish species characterized with complex trophic interactions. In this paper we described the trophic network of a fish community inhabiting a seagrass bed in the Venezuelan Caribbean. In addition, a consumption index (CI) for each prey ingested is proposed using two variables: abundance and consumption frequency. Eight samplings (at four time intervals: 6:00, 12:00, 18:00 and 24:00 hours) were done in August 2005 and January 2006. Fifty one fish species in 29 families were captured; Haemulidae was the most abundant. Crustacea was the most important food resource of the 28 food items identified. The relative importance of trophic guilds, considering abundance and taxonomic species richness, was: benthophagous>herbivorous>piscivorous. The features of the trophic network were: 1) high proportion of short chains (two links), 2) high number of intermediate species, 3) high consumption of benthos, 4) low CI values and 5) few species with a high number of linkages. Temporal (hourly and monthly) differences were obtained in fish species number (total, intermediate and top), total linkages, connectivity and maximal chain lengths. The connectance did not show significant temporal variation and it was similar to other environments with different species richness. In contrast, the connectivity was lower than the one reported for environments with low species richness. As in other reports, the temporal variation of the trophic parameters and the community structure was different. The values of CI for the different preys were low except for harpacticoid copepods and crustacean larvaes. The cluster value of CI was high for benthos (>80 %) and, in general, low for plankton and nekton preys. The seagrass bed studied was an important feeding place where the configuration of trophic network changed in different temporal scales and reflected the dynamic of the feeding relationships this fish community.

Venezuela has suffered a severe academic and research management crisis and funding opportunities for marine research and data management have been practically absent. This has worsened over the past five years and, as a result, libraries and other institutional spaces have been repeatedly vandalised, with hundreds of records, specimens and historical data stolen, destroyed or burned. To avoid the loss of irreplaceable data on Venezuelan biodiversity, an initiative was promoted, aimed at digitising information to create a rich dataset of biodiversity records, with emphasis on marine protected areas for the country, as well as to fill gaps in the distribution and status of marine biodiversity in Venezuela. Nighteen (19) institutions in the country focusing on marine science have consistently produced a wealth of information about Venezuela’s marine biodiversity in the form of specimen collections, unpublished sampled data and research theses through the work of hundreds of researchers and students. An inventory of available data sources at these national institutions was conducted under the National Biodiversity Data Mobilization Grant and the Biodiversity Information for Development Program, together with the Global Biodiversity Information Facility (GBIF) support. All recovered and processed datasets were published in the Ocean Biodiversity Information System (OBIS) and the Global Biodiversity Information Facility (GBIF) repositories. This occurrences data collection represents a major contribution to the marine biodiversity inventory in Venezuela. It is based on numerous published papers, reports, books and checklists provided by experts, covering a broad taxonomic collection from which we obtained species occurrences (present and absent), organised into 59 datasets containing 40,881 records. This represents a 28.49% contribution to the records of the Venezuelan marine biodiversity reported to the OBIS (143,513 records in the OBIS until November 2022). The extracted data showed 3,041 marine species, with representatives of each of the six kingdoms: Animalia, Chromista, Bacteria, Plantae, Fungi and Protozoa. The datasets provide information on occurrence since 1822, extending the temporal coverage of the species occurrence inventory for Venezuela, which was established in 1879 before this project. The number of records for Venezuela increased by 41.3% compared with the data available before the project. Most of the occurrences (63.47%) were registered in Marine Protected Areas. Data collection included records of non-native species, descriptions of new species and species listed under different IUCN categories.

Venezuela has suffered a severe academic and research management crisis, and funding opportunities for marine research and data management have been practically absent. This has worsened over the past five years, and as a result, libraries and other institutional spaces have been repeatedly vandalized, with hundreds of records, specimens, and historical data stolen, destroyed, or burned. To avoid the loss of irreplaceable data on Venezuelan biodiversity, an initiative aimed at digitizing information to create a rich dataset of biodiversity records, with emphasis on marine protected areas for the country, as well as to fill gaps in the distribution and status of marine biodiversity in Venezuela. Around 10 institutions in the country focusing on marine science have consistently produced a wealth of information about Venezuela’s marine biodiversity in the form of specimen collections, unpublished sampled data, and research theses through the work of hundreds of researchers and students. An inventory of available data sources at these national institutions was conducted under the National Biodiversity Data Mobilization Grant and the Biodiversity Information for Development Program, together with the Global Biodiversity Information Facility (GBIF) support. All recovered and processed datasets were published in the Ocean Biodiversity Information System (OBIS) and the Global Biodiversity Information Facility (GBIF) repositories. This data collection represents a major contribution to the marine biodiversity inventory in Venezuela. It is based on numerous published papers, reports, books, and checklists provided by experts, covering a broad taxonomic collection of 3,041 marine species, with representatives of each of the five kingdoms: Animalia, Chromista, Bacteria, Plantae, and Protozoa. The datasets provide information on occurrence since 1822, extending the temporal coverage of the species occurrence inventory for Venezuela, which was established in 1879 before this project. The species occrrences are organized into 59 datasets containing 40,881 records, which represent a 28.49% contribution to the records of Venezuelan marine biodiversity reported to the OBIS (143,513 records in OBIS until November 2022). The number of records for Venezuela increased by 41.3% compared with the data available before the project. Most of the occurrences (63.47%) were registered in Marine Protected Areas. Data collection included records of non-native species, descriptions of new species, and species listed under different IUCN categories.