Fishing monitoring to gather fishery dynamic data is usually land‐based or carried from onboard inspections. However, direct georeferencing of fishing activities using aerial drones is a versatile ...and easy option that can potentially improve fishery studies, especially in Marine Protected Areas. We investigated the utility of aerial images to understand spatial displacement and fishing territoriality in a Brazilian MPA system under risk of deregulation. Survey flights were conducted in the multiple use area where fishing is allowed in the Fernando de Noronha Archipelago, located in the South Atlantic Ocean and considered one of the main ecotourism destinations and marine conservation sites in Brazil. An aircraft was used to map and detect several aspects of fishing activities and shallow seabed characteristics to demonstrate its utility for fishery management. We recorded 89 fishing activities in the marine area and 75 shore fishers on beaches. Results documented areas most intensively targeted by fishers, and operational aspects of fishing effort, both onboard and shoreline activities targeting shoals. Enforcement and monitoring efforts must be strengthened to assess the impact of expanded fishing activity in this marine sanctuary, mainly due to fading conservation rules imposed by top‐down political decisions. This aerial approach demonstrates the utility of quantifying and mapping fishing activities to assist both MPA and fisheries management aligned to benchmarks for biodiversity conservation and human‐based demands.
Studies on the distribution and evolution of organisms on oceanic islands have advanced towards a dynamic perspective, where terrestrial endemicity results from island geographical aspects and ...geological history intertwined with sea-level fluctuations. Diversification on these islands may follow neutral models, decreasing over time as niches are filled, or disequilibrium states and progression rules, where richness and endemism rise with the age of the archipelago owing to the splitting of ancestral lineages (cladogenesis). However, marine organisms have received comparatively little scientific attention. Therefore, island and seamount evolutionary processes in the aquatic environment remain unclear. Here we analyse the evolutionary history of reef fishes that are endemic to a volcanic ridge of seamounts and islands to understand their relations to island evolution and sea-level fluctuations. We also test how this evolutionary history fits island biogeography theory. We found that most endemic species have evolved recently (Pleistocene epoch), during a period of recurrent sea-level changes and intermittent connectivity caused by repeated aerial exposure of seamounts, a finding that is consistent with an ephemeral ecological speciation process. Similar to findings for terrestrial biodiversity, our data suggest that the marine speciation rate on islands is negatively correlated with immigration rate. However, because marine species disperse better than terrestrial species, most niches are filled by immigration: speciation increases with the random accumulation of species with low dispersal ability, with few opportunities for in situ cladogenesis and adaptive radiation. Moreover, we confirm that sea-level fluctuations and seamount location play a critical role in marine evolution, mainly by intermittently providing stepping stones for island colonization.
This study investigated the ingestion of microplastics and artificial cellulose particles by 103 specimens belonging to 21 reef fish species from the southwestern Atlantic. Specimens of six species ...had ingested microplastics and artificial cellulose particles, while those of another three species had ingested only one type of material. In our samples, man-made cellulose fibers were more common than microplastics. The tomtate grunt, Haemulon aurolineatum, ingested more particles than any of the other species. Overall, transparent particles were predominant, and polyamide was the most common plastic material. Household sewage, fishery activity, and navigation appear to be the principal sources of the artificial particles ingested by the reef fishes. Our results provide an important database on oceanic contamination by microplastics and artificial cellulose particles. Understanding this impact on tropical reef fish will contribute to the development of strategies to mitigate pollution by anthropogenic debris in reef systems.
•Reef fishes ingested more man-made cellulose fibers than microplastics.•Transparent particles were predominant in the samples.•Household sewage, fishery and navigation are likely the main sources of particles.
Three sardine species of
Harengula
and one of
Opisthonema
(Clupeiformes, Clupeidae) are known in the Western Atlantic, where the Amazon-Orinoco plume has been recognized as a major biogeographic ...barrier, albeit permeable to larger and generalist species. Here we used mitochondrial
cox1
gene DNA sequences to check the lineage delimitation of both genera, testing the influence of the Amazon-Orinoco barrier (AOB) and marine provinces on their phylogeographic structure. Results indicate that the two genera are differently affected by the AOB, including cryptic speciation in
Harengula
and population structure in
Opisthonema
.
Harengula
show a broad distribution in the Brazilian Province (BRA) distinct from
H. clupeola
and
H. jaguana
from the Greater Caribbean Region (GCR). Divergence time between
Harengula
from the GCR
vs
. BRA was estimated as about 2.4 Mya, which coincides with the period of increasing sediment and freshwater discharge of the Amazon River in the Atlantic. Results also indicate the existence of a single species of
Opisthonema
, albeit with population structuring related to the marine provinces. Since species of both genera are relevant to artisanal fisheries and the maintenance of oceanic ecosystems, these results may help in fisheries management of these important marine resources.
Declines and extinctions are increasing globally and challenge conservationists to keep pace with biodiversity monitoring. Organisms leave DNA traces in the environment, e.g., in soil, water, and ...air. These DNA traces are referred to as environmental DNA (eDNA). The analysis of eDNA is a highly sensitive method with the potential to rapidly assess local diversity and the status of threatened species. We searched for DNA traces of 30 target amphibian species of conservation concern, at different levels of threat, using an environmental DNA metabarcoding approach, together with an extensive sequence reference database to analyse water samples from six montane sites in the Atlantic Coastal Forest and adjacent Cerrado grasslands of Brazil. We successfully detected DNA traces of four declined species (Hylodes ornatus, Hylodes regius, Crossodactylus timbuhy, and Vitreorana eurygnatha); two locally disappeared (Phasmahyla exilis and Phasmahyla guttata); and one species that has not been seen since 1968 (putatively assigned to Megaelosia bocainensis). We confirm the presence of species undetected by traditional methods, underscoring the efficacy of eDNA metabarcoding for biodiversity monitoring at low population densities, especially in megadiverse tropical sites. Our results support the potential application of eDNA in conservation biology, to evaluate persistence and distribution of threatened species in surveyed habitats or sites, and improve accuracy of red lists, especially for species undetected over long periods.
Amphibians are facing population declines and extinctions across the globe, and megadiverse Brazil is no exception. One of the global hotspots of amphibian declines is Brazil's Atlantic Forest (AF), ...an ecoregion that in the past covered over 1,300,000 km2 of luxuriant coastal rainforests. Reports of historical declines were concentrated in the southern and southeastern sections of AF, however we now propose that these reports did not capture the whole extent and complexity of historical amphibian declines. Here, we conducted a refined review of historical amphibian declines that have been linked to environmental factors, climatic anomalies, and the emergence of the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). We reviewed data on 169 populations of 106 species that have undergone population declines in the southern and southeastern Atlantic Forest, more than doubling the number of population declines reported in previous studies. These numbers place the Atlantic Forest among the ecoregions with the highest rates of amphibian declines and extinctions globally. We provide novel spatiotemporal information of amphibian declines, underscoring that the peak of declines happened in 1979, and that population recoveries, when they occurred, often took over 30 years. Our analyses indicate that the volume of field collections accessioned in museums over time matched temporal patterns of declines and extinctions, which indicates that historical declines might have impacted a far larger number of amphibian populations and species. Our review helps guide targeted management programs for amphibian surveys and Bd surveillance with practical implications for conservation.
•Brazil's Atlantic Forest is the place on Earth with the highest number of amphibian population declines ever reported.•The number of declines reported in the present study roughly doubles previous estimates.•The peak of amphibian declines was in 1979.•Declined populations took 21 years in mean to recover.•Museum records supports a large-scale amphibian die-off in the Atlantic Forest.
The mechanisms driving the ecology and biodiversity of seamount communities are still unclear. Here we analyzed the distribution and species traits of reef fish species recorded over seamounts, ...oceanic islands, and the continental shelf of the southwestern Atlantic Ocean to understand the influence of mechanisms of dispersal and establishment in these ecosystems. Species richness did not decrease with distance from the mainland, and community composition was not related to geographic position and geological history of seamounts and oceanic islands. Similarity among sites was explained by habitat heterogeneity, shallowest depth, and distance from mainland. Inter-site isolation had a significant influence on the spatial turnover of species. All species traits related to dispersal and establishment worked as ecological filters driving the composition of communities and distribution of species along seamounts and oceanic islands. We conclude that seamount communities are closely related to those of oceanic islands, with the stepping-stones (inter-site isolation) process being the most important one shaping species composition and distribution. Establishment and dispersal mechanisms, in combination with historical sea-level fluctuations, regulate the persistence of species and the similarity of communities among adjacent and environmentally similar sites.
Visual records, radio interviews and onboard observations of the fishing activities during a 58 days scientific expedition to Trindade Island and the Martin Vaz Archipelago were obtained from ...February to April 2007. The regular activities of four different fisheries were observed: pelagic longline, bottom line, trolling and handline. These fisheries caused mortality of at least seven species with some level threat, according to the International Union for Conservation of Nature list. The establishment of specific restriction norms for hook-and-line activities around the oceanic islands was seen as an alternative for the conservation of the ichthyofauna of the region. Satellite monitoring to track the fishery vessels could be established through the national program as another legal mean to diminish fishing the impact.
Reportamos atividades de pesca comerciais no complexo insular mais afastado da costa brasileira: Ilha da Trindade e Arquipélago Martin Vaz. As atividades foram estudadas através de embarques e entrevistas com os mestres e pescadores das embarcações durante uma expedição cientifica realizada entre fevereiro e abril de 2007. Quatro modalidades de atividades de pesca são realizadas na região, capturando ao menos sete espécies que possuem algum risco de extinção. O estabelecimento de normas específicas de restrição para atividades que pescam sobre os recifes das ilhas é uma alternativa para a conservação das espécies ameaçadas. O monitoramento das embarcações pode ocorrer via satélite através do programa nacional de rastreamento de embarcações pesqueiras (PREPS).
Seamounts and oceanic islands play an important role as biodiversity hotspots amid the vastness of the oligotrophic open ocean. While island ecology and evolution have received a lot of attention in ...the last decades, the exploration and understanding of community and habitat dynamics of seamounts remain challenging. Here, we investigate the ecology and biogeography of fish and benthic communities of a recently discovered southwestern Atlantic reef system at Davis seamount. This seamount belongs to the Vitória-Trindade Chain and is located in international waters off the Brazilian coast. We present this reef system, that also occurs on other shallow seamounts of the chain, as a new reef habitat named “Coralline Hills”: Its hill-shaped structure is mainly built by crustose coralline algae and rises up from the seamount summit at 60–70 m to 17 m depth. The benthic community is mainly composed by coralline algae and sponges. Fish biomass at Davis coralline hill is dominated by carnivores, mainly top predators such as nurse sharks and large groupers. The relatively shallow reef top presents higher species richness, abundance and distinct trophic structure (mostly omnivore and planktivore species) than the mesophotic zone (with higher abundance of carnivorous fishes). A biogeographic analysis revealed that the reef fish community structure is greatly influenced by a set of dispersal and establishment traits that strongly differs from that encountered on coastal reefs of the central Brazilian coast and on insular reefs of Trindade Island. Gathering information about the ecology and structure of such unique and remote habitat is timely, since the region is under imminent threat such as fishing and mining and lacks international attention.
Patterns of community structure in the marine environment are strongly influenced by population relationships to biotic and physical gradients. The aim of this work is to explore the relationships of ...tropical rocky reef fish assemblages to wave exposure and benthic coverage in a gradient of distance from the coast. The study was conducted on the Guarapari Islands, southeastern Brazilian coast. Fish were sampled by underwater visual census (166 transects) and benthic cover was estimated with quadrats (223 replicates). Two main kinds of habitats were found to be derived from the close interrelation between exposure and benthic coverage: (1) exposed areas subjected to major hydrodynamic forcing, and (2) sheltered or moderately exposed areas. The first group is associated with mid-water schooling species like planktivorous labrids and Chromis, piscivorous Caranx, as well as gregarious omnivores like Abudefduf and Diplodus. In terms of benthic composition, macroalgae and encrusting calcareous algae prevail in this high-energy habitat. The second group is characterized by site-attached and reef associated species like territorial pomacentrids, invertebrate feeders such as Halichoeres poeyi and Chaetodon striatus, and small cryptobenthic fishes (e.g. blenniids and labrisomids). Turf algae, zoanthids and massive corals dominate this environment. Environmental plasticity is also common with some genera showing high abundances in all habitats (e.g. Holocentrus, Haemulon, Acanthurus). Examples of the coupling of food availability and fish abundance were found. Planktivores, territorial herbivores, macroalgae browsers and spongivores were positively related with the abundance of their preferred food items along the exposure gradient. Within-family analyses of Pomacentridae and Labridae showed that niche partitioning is likely occurring and seems to be mediated by swimming 'ability' and associated feeding performance.
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