Integrated ecosystem assessment around islands of the tropical South Mid-Atlantic Ridge

The South Mid Atlantic Ridge comprises three main oceanic islands in the equatorial and tropical portions of the Atlantic Ocean. These islands are isolated from each other and equidistant from both the continental margins of South America and Africa, sharing common patterns but with different types of human use and pressures. Moreover, the areas beyond national jurisdiction between those islands are visited and exploited by distant fishing fleets and include large areas of shipping activity for commodities. Here, a pioneering integrated ecosystem assessment (IEA) process is constructed for the region among Saint Peter and Saint Paul’s Archipelago (Brazil), Saint Helena Island and Ascension Island (UK overseas territories). For that, we used a qualitative assessment of risks arising from anthropogenic activities, representing a novel contribution to the field. The Options for Delivering Ecosystem-Based Marine Management (ODEMM) approach was applied to trace sector–pressure–component pathways. A ‘linkage framework’ was outlined including pressures affecting each ecosystem component, and supported a process of knowledge attributions that scored the impact risks. All results were validated with regional stakeholders through workshops, including local and international management bodies, non-governmental organizations (NGOs) and scientists. The approach focused on a significant area among encompassing the open ocean, shallow and deep-sea biomes, analyzing the main sectors and pressures affecting the ecological components. Our results identified 14 sectors and 16 key pressures associated with 23 ecosystem components, totaling 780 impact chains. Fishing, shipping, wastewater, and tourism/recreation appeared as the top impacting sectors. Fishing and shipping were the most connected with ecosystem components links. Litter, species extraction, contaminants, and bycatch were the pressures that had the highest risk of impact values. Lastly, demersal and pelagic fish and pelagic and demersal elasmobranchs were the groups with the highest risk related to overall impacts, which were supported by local and regional evidence from long term monitoring programs and local studies. Our study demonstrated that these seemingly pristine islands and oceanic waters are already experiencing human impacts that should be addressed by local both conservation measures and international agreements. We also highlight the pressures that should be prioritized for better monitoring and policy, as well as those linkage components that have been less investigated

Hyperdominance and habitat composition drive reef fish foraging on Atlantic oceanic islands

<p>Spatial and temporal patterns of benthic community structure play a crucial role in shaping reef habitats and have a direct impact on fish foraging dynamics, alongside density-dependence effects on the whole community. In isolated oceanic islands, the relatively low fish species richness often leads to the hyperdominance of a few species and a general reduced trophic redundancy. However, the influence of benthic habitat features and hyperdominant species on foraging selection in oceanic islands has been largely overlooked. This study aimed to investigate, using Remote Underwater Videos (RUVs), whether reef fishes consistently forage on specific habitats across five different oceanic islands in the Atlantic Ocean, especially focusing on the importance of the role of hyperdominant species. We analysed 295 RUVs, within 2m2 areas (3-15 m deep), totalling 49 hours of video. Photoquadrats were utilised to gauge benthic group coverage in the same habitats. Our results revealed five prevalent habitats and six fish trophic groups interacting with reef benthos. The intensity of feeding pressure varied across islands, depending on the diversity of habitats. Herbivores and omnivores exhibited the highest feeding pressure, with omnivores foraging on crustose coralline algae and macroalgae habitats, while herbivores primarily fed on habitats dominated by the epilithic algal matrix. Hyperdominant species forage in multiple habitats, indicating a comparatively high degree of dietary plasticity. Our findings also demonstrated that fish feeding pressure is influenced by both habitat features and fish biomass. Therefore, our study can provide valuable insights for prioritising the management of key species in isolated oceanic reefs.</p&gt

Under pressure: an integrated assessment of human activities and their potential impact on the ecosystem components of the Southern Brazilian continental shelf

Abstract Economic activities in the South Brazilian Shelf (SBS) are concentrated on the coast, causing several impacts. To balance biodiversity and habitat conservation in coastal and marine areas with human activities relevant to society, it is important to identify and understand those sectors and pressures. We conducted an analysis to assess ecosystem risks from multiple drivers and pressures in the continental shelf that extends from the Southernmost point of Brazil (Chuí) to Cabo Frio cape, in Rio de Janeiro State. We used the Integrated Ecosystem Assessment (IEA) methodology, a framework for implementing ecosystem-based management grounded on five steps: scoping, indicator development, ecosystem assessment, risk analysis, and management strategy evaluation. This work presents the scoping step consisting of a semi-quantitative assessment identifying sector–pressure–ecological component pressure pathways. Subsequently, these pathways were scored using expert judgment supported by literature and data, regarding their level of overlap with each ecosystem component, frequency of occurrence, and degree of impact, enabling estimation of the magnitude of impact risk arising from each one of the sectors and pressures. The assessment involved 20 experts from multiple disciplines and backgrounds. To validate the results, we conducted a thorough literature review and engaged in further discussions with relevant stakeholders. As a result, 16 sectors and 19 pressures were identified as impacting 18 ecological components. Fishing, land-based industry, tourism and recreation, wastewater, and coastal infrastructure represented the main economic sectors impacting the area. The major associated pressures were the incidental catch of species, the introduction of contaminants and organic matter into the water, and the generation of waste. The most affected ecosystem components were, in turn, those located on or close to the coast, such as mangroves, saltmarshes, and rocky reefs while the preeminent impacted taxonomic groups were elasmobranchs, seabirds, reptiles, mammals, and bony fish. The literature review supported the expert assessment, and the stakeholders’ workshop endorsed our findings. Additionally, this assessment highlights the need to implement public policies that focus on reducing the impact of the most influential sectors and pressures and the necessity of strengthening research and monitoring. Identifying these priorities for integrated coastal and marine management is crucial, and our research outcomes can be key in promoting regional ocean sustainability

TimeFISH: Long-term assessment of reef fish assemblages in a transition zone in the Southwestern Atlantic

The TimeFISH database provides the first public time-series dataset on reef fish assemblages in the southwestern Atlantic (SWA), comprising 15 years of data (2007–2022) based on standardized Underwater Visual Censuses (UVCs). The rocky reefs covered by our dataset are influenced by pronounced seasonal cycles of ocean temperatures with warm tropical waters from the Brazil Current in the summer (~27°C) and colder waters from the La Plata River Plume discharge and upwelling from the South Atlantic Central Water in the winter (~18°C). These oceanographic conditions characterize this area as the southernmost tropical–subtropical climatic transition zone in the Atlantic Ocean. As a result, reef fish assemblages are comprised of both tropical and subtropical species. All records included in TimeFISH were collected using UVCs, a nondestructive method that allows the estimation of fish species richness, abundance, and body size distributions. UVCs were performed through 40 m2 belt transects by scuba diving in nine locations along the southern Brazilian coast (25–29°S). Four of these locations lie within the boundaries of the no-entry Arvoredo Marine Biological Reserve, where fishing and recreational activities are forbidden, and the remaining locations are unprotected from these activities. During each belt transect, a diver swam at a constant depth above and parallel to the reef, identifying fish species, counting the number of individuals, and estimating the total body length (Lt in cm) of all detected individuals. All fish individuals in the water column (up to 2 m above the substratum) and at the bottom were targeted. In total, 202,965 individuals belonging to 163 reef fish species and 53 families were recorded across 1857 UVCs. All survey campaigns were funded by either public or mixed capital (private–public) sources, including seven grants from the Brazilian federal and Santa Catarina state governments. Part of the data has already been used in multiple MS.c. and Ph.D. theses and scientific articles. TimeFISH represents an important contribution for future studies aiming to examine temporal and spatial variations of reef fish assemblages in transition zones. No copyright restrictions apply to the use of this data set, other than citing this publication

Effect of indomethacin on the pregnant rat

The objective of this study was to evaluate the reproductive performance, liver morphological study and post mortem characteristics of the pregnant Wistar rats treated with indomethacin, a general COX inhibitor. Indomethacin at doses of 0 (control), 0.32, 1.68 and 8.40 mg/kg/day were orally given once daily to each group (n=10) on days 3 and 4 of pregnancy (day 0 = first day of pregnancy = positive vaginal sperm). The animals were euthanized under anesthesia on day 11 of pregnancy, and were carried out necropsy and microorganism culture study. The results showed that the doses of 0.32 and 1.68 mg/kg body weight (the therapeutic dose for humans) of indomethacin caused no embryotoxic or lethal effects. The highest dose (8.40 mg/kg) of indomethacin disturbed implantation process and, thus, interrupted major development in some fetuses. The peritonitis was detected in the necropsy and in the bacteriological study of the animals treated with 8.4 mg/kg. It was considered death cause of these animals. Thus, this study analyzed a pharmacological agent on pregnancy in rodents and it provided some evidences that indomethacin presented embryotoxic and lethal effects at a high dose, but it was safe in the therapeutic dose used for humans.<br>O objetivo deste trabalho foi avaliar a performance reprodutiva, estudo morfológico do fígado e características " post mortem" de ratas Wistar prenhes tratadas com indometacina, um inibidor geral de COX. Indometacina foi administrada oralmente, nas doses de 0 (controle), 0,32, 1,68 e 8,40 mg/kg/dia (n=10/grupo), nos dias 3 e 4 de prenhez (dia 0 = primeiro dia de prenhez = esperma positivo). Os animais foram eutanasiados sob anestesia no 11º dia de prenhez, e foram realizadas necropsia e cultura de microorganismos. Os resultados mostraram que as doses de 0,32 e 1,68 mg/kg de peso corpóreo (dose terapêutica para humanos) de indometacina não causaram efeitos embriotóxicos ou letais. A maior dose (8,40 mg/kg) de indometacina prejudicou o processo de implantação e, portanto, interferiu no desenvolvimento fetal. A peritonite foi detectada na necropsia e nos estudos bacteriológicos dos animais tratados com 8,4 mg/kg e considerada a causa-morte destes animais. Portanto, este estudo analisou um agente farmacológico na prenhez de roedores e evidenciou que a indometacina apresentou efeitos embriotóxicos e letais na maior dose empregada, mas foi segura na dose terapêutica usada pelo homem