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We used shore boulders that had been previously colonized, and were scattered in a seagrass bed as models for islands. We tested two predictions of Island Biogeography theory: (1) small boulders harbored fewer species than large boulders, and (2) small boulders had higher rates of extinction than large boulders, as reflected in higher faunal replacement variability. We detected a definite relation between species richness and boulder size although not for all statistical models. We did not confirm higher compositional variability in small boulders.

Landings of the artisanal fishery in the Colombian Caribbean from 2013 to 2021 were characterized by means of two indicators: the trophic level and the vulnerability to fishery landings. Indicators showed a statistically significant decreasing trend in vulnerability and trophic level, suggesting that the fishery is increasingly targeting species of low vulnerability and trophic level, thus moving down the food web. The overall pattern of indicators was not uniform in space. Incidence interaction of gears and species landed explained the trajectory of indicators at the scale of Departments. Fishing gears targeted different levels in the food web, with gillnets responsible for the bulk of landings. Compared to a previous study, the group of fish species supporting most of landings has changed towards species with lower vulnerability, i.e. resistant to fishing mortality due to their evolved life-history but still of predatory habits in general. A notable exception is Mugil incilis, a species with a low trophic level that has become third in importance of landings in the database.

We compiled georeferenced records of deep demersal fishes from the Colombian Caribbean Sea in order to assess the level of survey coverage and geographic completeness of species richness inventories at a scale of 15 min by 15 min cells, in view of threats from fishing and oil and natural gas exploration. We identified a rich fauna with a minimum of 362 species registered. Areas with high observed and predicted species richness were identified. Survey coverage and geographic richness completeness resulted in being deficient with no cell reaching the status of well-sampled spatial unit, being 83% of the Colombian Caribbean Exclusive Economic Zone bottoms unexplored, particularly depths beyond 1,000 m. A plea is made for renewed survey efforts with a focus on the protection of the Colombian Caribbean deep-sea biota.

This study presents a spatial analysis of species richness of soft-bottom bony and cartilaginous fish species in the Colombian Caribbean. The dataset consisted of 625 species distributed among 15651 georeferenced occurrences. The global richness completeness analysis suggests that the list is close to completion but that probably more species await being registered at greater depths. In spatial terms, our knowledge of fish richness remains incomplete as none of the spatial units, in which the general area was divided reached 100 % completeness and few reached 70 % or higher completeness probably due to the incidence of numerous rare species. The Guajira, Palomino, Tayrona and Golfo de Salamanca zones, displayed the highest observed and predicted richness. The Galerazamba, Arco (coralline archipelago) and Arboletes zones were predicted to have high species richness. In view of the results, marine protected areas need to be expanded to include soft-bottom habitats. Future research efforts should focus on the high species richness areas observed and predicted and surveys should include more extensively depth locations.

La Guajira es un ecosistema de surgencia explotado en la costa del Caribe colombiano. Con el propósito de integrar la información disponible sobre el sistema se construyó un modelo trófico de 27 grupos funcionales usando el programa Ecopath 5.0 Beta. Se obtuvo una base cuantitativa para compararlo con otros sistemas de surgencia. La Guajira presenta una biomasa total de 68 t/km²/año, la producción primaria neta del sistema es de 1 248.51 t/km²/año y las transferencias totales del sistema son de 3 275 t/km²/año, lo que indica un ecosistema con una surgencia moderada comparada con otros sitios. Las mayores transferencias de energía se dan del nivel trófico I-II (68.93 %), aunque existe una importante proporción de flujos al detritus (32 %). Los resultados en los atributos de madurez del sistema sugieren que La Guajira es un ecosistema inmaduro debido a que la relación P/R excede a 1 y está en desarrollo debido a la baja ascendencia (33.7 %) y alta capacidad de desarrollo (66.3 %) como ocurre con otras surgencias donde se presentan valores de ascendencia entre 20 % y 35 %. Aunque los datos básicos de entrada en el modelo fueron buenos, gracias a las investigaciones que se han elaborado entre 1995 y 2000, existen algunos grupos donde no se encuentra aún información adecuada; especialmente en los valores de biomasa del fitoplancton, invertebrados, bagres, peces depredadores pelágicos, así como estimaciones de producción en invertebrados, peces depredadores pelágicos y peces pequeños pelágicos. No existe una cuantificación de las poblaciones de mamíferos y aves en el área de estudio, los cuales constituyen depredadores superiores y hacen parte esencial en sistemas de surgenciaBiomass flow and structure of a tropical upwelling ecosystem in La Guajira, Colombian Caribbean. La Guajira is an exploited tropical upwelling ecosystem in the Colombian Caribbean coast. A trophic model of 27 functional groups was constructed using the ECOPATH 5.0 Beta software to integrate the available information on the ecosystem. The model allowed a comparison with other trophic flow models of upwelling ecosystems. Total system biomass (68 t/km²/year), net system production (1248.5 t/km²/year), and total system throughput (3 275 t/km²/year) make La Guajira moderate when compared with other systems. The largest amount of energy throughput is achieved from trophic level I to II (68.93 %), although an important proportion of the total flow originates from detritus (32 %). The production/respiration ratio exceeds 1, suggesting that La Guajira is an immature ecosystem and is in development, as determined by its low ascendency (33.7 %) and high development capacity (66.3 %), similar to other upwellings that have values of ascendency between 20 % and 35 %. Although the basic input data were good and covered 1995 to 2000, appropriate information is still not available on some trophic groups such as biomass (for phytoplankton, invertebrates, catfishes and pelagic predator fishes), secondary production data (invertebrates, pelagic predator fishes, and small pelagic fishes), and seabird and mammal populations, which are top trophic levels and an essential part of upwelling ecosystems. Rev. Biol. Trop. 54 (4): 1257-1282. Epub 2006 Dec. 15

Se sugiere un nuevo método de censo para comunidades bentónicas sésiles que tiene en cuenta la epibiosis y la complejidad comunitaria. La distribución entre sitios y vertical de especies es examinada en sitios con alto y bajo oleaje. Se examina como el oleaje determina mecanismos como el reclutamiento y algunas interacciones bióticas. Se relacionan estos mecanismos con la distribución vertical de las especies en las porciones de la raíz de mangle que están en el intermareal y en el submareal. Se propone un esquema idealizado de distribución vertical de especies para sitios con alto y bajo oleaje. La dinámica a pequeña escala fue examinada en huecos naturales de la biota sésil en las raíces de manglar. La recolonización de los huecos fue examinada y se relacionó con la teoría. La supervivencia de adultos, reclutas, organismos solitarios y coloniales fue examinada experimentalmente. Con la información experimental de la recolonización de los huecos y la supervivencia se examinaron las propiedades comunitarias de las comunidades naturales asociadas con raíces de Rhizophora mangle. Se relacionaron las propiedades comunitarias con la hipótesis del distur-bio intermedio. Se examinó experimentalmente la sucesión haciendo énfasis en el reemplazo direccional de especies. Se presentan las características de las comunidades en sitios con alto y bajo oleaje.

Succession studies on artificial substrates in the Bay of Santa Marta, Colombian Caribbean showed Balanus trigonus (Darwin) as one of the more prominent members of the fouling community. This fact prompted the interest for a closer examination of its biology. Four aspects were touched upon: recruitment, growth and mortality rates, and orientation with respect to the horizon line. Two hypotheses were tested. First, that orientation of individuals was random within the orientation range observed during succession, and second, that there was no relationship between orientation and age of the individuals. Larvae settling was found to occur throughout the year but with a well delimited peak in the dry season (January to April). The availability of competent larvae is reflected in the abundance of the species during succession. Growth and mortality proceed rapidly. Maximal growth (6.2 mm average carino-rostral distance) is reached in 20 weeks after settlement. Mortality is substantial: 50% of recruits, on average, died after 3-4 weeks from settlement. Orientation at settlement was found to be not random: for instance, 64% of individuals orientated between 0°-60° from the horizon. With age the orientation patterns at settlement changed statistically. Biological and ecological implications of these findings are discussed and comparisons made with other studies. It is concluded that Balanus trigonus could act as a model species for latitudinal comparisons in view of its wide distribution, adaptability and sessile habit.