El mundo oceánico: realidades, desafíos y amenazas

El océano ha cambiado rápidamente, durante los últimos cincuenta años. La sobreexplotación de los recursos marinos, el aumento de la contaminación costera, el calentamiento global y la acidificación oceánica no son fantasías generadas por los ecologistas

Monitoreo de fauna pelágica de los Montes submarinos del Pacífico colombiano usando BRUVS

In December 2021, we conducted the first expedition to the seamounts of the Malpelo and Yuruparí ridges. Eight seamounts were explored using Baited Remote Underwater Video Systems (BRUVS). A total of 48 BRUVS were deployed, registering five pelagic species (Sphyrna lewini, Mobula birostris, Pteroplatytrygon violacea, Kajikia audax and Istiophorus platypterus) where Pteroplatytrygon violacea constituted a new record for the region. Pelagic species were recorded in all seamounts, although sharks were exclusively associated with the seamounts to the west of the ridges, especially in the area known as Bajo Navegador, the shallowest seamount in the region. This work is a first step to guide the following explorations of these ecosystems.En diciembre de 2021 se desarrolló la primera expedición a los montes submarinos de las dorsales de Malpelo y de Yuruparí. En total se exploraron ocho montes submarinos por medio de BRUVS (Baited Remote Underwater Video Systems). Se desplegaron 48 BRUVS, registrando cinco especies pelágicas (Sphyrna lewini, Mobula birostris, Pteroplatytrygon violácea, Kajikia audax y Istiophorus platypterus), donde Pteroplatytrygon violácea constituyó un nuevo registro para la región. En todas las zonas se registraron especies pelágicas, aunque los tiburones se asociaron exclusivamente a los montes al oeste de las dorsales, en especial al monte conocido como Bajo Navegador, el más somero de la región. Este trabajo es un primer paso para orientar las siguientes exploraciones de estos ecosistemas

Richness distribution patterns of marine elasmobranchs in Colombia: Patrones de distribución de la riqueza de elasmobranquios marinos en Colombia

An analysis on the species richness distribution of marine sharks and batoids for the Colombian Caribbean and Pacific regions was carried out. A total of 138 species was documented in nearby marine waters off Colombia, including 76 sharks and 62 batoids; 20 species occurred on both coasts with the Caribbean generally having a higher observed richness than the Pacific. The Caribbean had high richness values both in the insular as well as in the northern region. However, the highest richness values per spatial unit in the Pacific islands of Gorgona and Malpelo, with completeness richness estimate represented mostly by values below 90%. Richness estimators showed values higher than the observed richness, indicating that the inventories and the description of marine shark and batoid richness in Colombia are still incomplete. Despite this, the results of this study are relevant to make decisions aimed at the conservation of this taxonomic group, both in marine protected and unprotected areas of the Pacific and Caribbean coasts of Colombi

Global collision-risk hotspots of marine traffic and the world’s largest fish, the whale shark

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Womersley, F. C., Humphries, N. E., Queiroz, N., Vedor, M., da Costa, I., Furtado, M., Tyminski, J. P., Abrantes, K., Araujo, G., Bach, S. S., Barnett, A., Berumen, M. L., Bessudo Lion, S., Braun, C. D., Clingham, E., Cochran, J. E. M., de la Parra, R., Diamant, S., Dove, A. D. M., Dudgeon, C. L., Erdmann, M. V., Espinoza, E., Fitzpatrick, R., González Cano, J., Green, J. R., Guzman, H. M., Hardenstine, R., Hasan, A., Hazin, F. H. V., Hearn, A. R., Hueter, R. E., Jaidah, M. Y., Labaja, J., Ladinol, F., Macena, B. C. L., Morris Jr., J. J., Norman, B. M., Peñaherrera-Palmav, C., Pierce, S. J., Quintero, L. M., Ramırez-Macías, D., Reynolds, S. D., Richardson, A. J., Robinson, D. P., Rohner, C. A., Rowat, D. R. L., Sheaves, M., Shivji, M. S., Sianipar, A. B., Skomal, G. B., Soler, G., Syakurachman, I., Thorrold, S. R., Webb, D. H., Wetherbee, B. M., White, T. D., Clavelle, T., Kroodsma, D. A., Thums, M., Ferreira, L. C., Meekan, M. G., Arrowsmith, L. M., Lester, E. K., Meyers, M. M., Peel, L. R., Sequeira, A. M. M., Eguıluz, V. M., Duarte, C. M., & Sims, D. W. Global collision-risk hotspots of marine traffic and the world’s largest fish, the whale shark. Proceedings of the National Academy of Sciences of the United States of America, 119(20), (2022): e2117440119, https://doi.org/10.1073/pnas.2117440119.Marine traffic is increasing globally yet collisions with endangered megafauna such as whales, sea turtles, and planktivorous sharks go largely undetected or unreported. Collisions leading to mortality can have population-level consequences for endangered species. Hence, identifying simultaneous space use of megafauna and shipping throughout ranges may reveal as-yet-unknown spatial targets requiring conservation. However, global studies tracking megafauna and shipping occurrences are lacking. Here we combine satellite-tracked movements of the whale shark, Rhincodon typus, and vessel activity to show that 92% of sharks’ horizontal space use and nearly 50% of vertical space use overlap with persistent large vessel (>300 gross tons) traffic. Collision-risk estimates correlated with reported whale shark mortality from ship strikes, indicating higher mortality in areas with greatest overlap. Hotspots of potential collision risk were evident in all major oceans, predominantly from overlap with cargo and tanker vessels, and were concentrated in gulf regions, where dense traffic co-occurred with seasonal shark movements. Nearly a third of whale shark hotspots overlapped with the highest collision-risk areas, with the last known locations of tracked sharks coinciding with busier shipping routes more often than expected. Depth-recording tags provided evidence for sinking, likely dead, whale sharks, suggesting substantial “cryptic” lethal ship strikes are possible, which could explain why whale shark population declines continue despite international protection and low fishing-induced mortality. Mitigation measures to reduce ship-strike risk should be considered to conserve this species and other ocean giants that are likely experiencing similar impacts from growing global vessel traffic.Funding for data analysis was provided by the UK Natural Environment Research Council (NERC) through a University of Southampton INSPIRE DTP PhD Studentship to F.C.W. Additional funding for data analysis was provided by NERC Discovery Science (NE/R00997/X/1) and the European Research Council (ERC-AdG-2019 883583 OCEAN DEOXYFISH) to D.W.S., Fundação para a Ciência e a Tecnologia (FCT) under PTDC/BIA/28855/2017 and COMPETE POCI-01–0145-FEDER-028855, and MARINFO–NORTE-01–0145-FEDER-000031 (funded by Norte Portugal Regional Operational Program [NORTE2020] under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund–ERDF) to N.Q. FCT also supported N.Q. (CEECIND/02857/2018) and M.V. (PTDC/BIA-COM/28855/2017). D.W.S. was supported by a Marine Biological Association Senior Research Fellowship. All tagging procedures were approved by institutional ethical review bodies and complied with all relevant ethical regulations in the jurisdictions in which they were performed. Details for individual research teams are given in SI Appendix, section 8. Full acknowledgments for tagging and field research are given in SI Appendix, section 7. This research is part of the Global Shark Movement Project (https://www.globalsharkmovement.org)

Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes

Copyright: © 2011 Mora et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas

Global Spatial Risk Assessment of Sharks Under the Footprint of Fisheries

Effective ocean management and conservation of highly migratory species depends on resolving overlap between animal movements and distributions and fishing effort. Yet, this information is lacking at a global scale. Here we show, using a big-data approach combining satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively) and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of high-seas fishing effort. Results demonstrate an urgent need for conservation and management measures at high-seas shark hotspots and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real time, dynamic management

First record of giant trevally (Caranx ignobilis)around the Clipperton Atoll-La Passion Island(North-Eastern Tropical Pacific)

International audiencePremière identification de la carangue grosse tête(Caranx ignobilis) autour de l’île de Clipperton-La Passion (océanTropical Nord-Est).Une mission réalisée en février 2016 sur l’île de Clipperton-LaPassion (océan Tropical Nord-Est) a permis l’identification inéditede la carangue grosse tête Caranx ignobilis (Forsskål, 1775)

Data from: Conservation genetics of the scalloped hammerhead shark in the Pacific coast of Colombia

Previous investigations of the population genetics of the scalloped hammerhead sharks (Sphyrna lewini) in the Eastern Tropical Pacific have lacked information about nursery areas. Such areas are key to promoting conservation initiatives that can protect young sharks from threats such as overfishing. Here, we investigated the genetic diversity, phylogeography, and connectivity of S. lewini found in 3 areas of Colombia’s Pacific coast: around Malpelo Island and in 2 National Natural Parks on the Colombian Pacific mainland (Sanquianga and Ensenada de Utría). We analyzed mtDNA control region (CR) sequences and genotyped 15 microsatellite loci in 137 samples of adults and juveniles. The mtDNA analyses showed haplotypes shared between the Colombian Pacific individuals sampled in this investigation and other areas in the Eastern Tropical Pacific, the Indo-Pacific, and with sequences previously reported in Colombia (Buenaventura Port), as well as 4 unique haplotypes. Population assignment and paternity analyses detected 3 parent–offspring pairs between Malpelo and Sanquianga and 1 between Malpelo and Utría. These results indicate high genetic connectivity between Malpelo Island and the Colombian Pacific coast, suggesting that these 2 areas are nurseries for S. lewini. This is, to our knowledge, the first evidence of nursery areas identified for the scalloped hammerhead shark anywhere in the world. Additional conservation planning may be required to protect these nursery habitats of this endangered shark species