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1.
Nat Commun ; 11(1): 6255, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-33288746

RESUMO

Oceans provide critical ecosystem services, but are subject to a growing number of external pressures, including overfishing, pollution, habitat destruction, and climate change. Current models typically treat stressors on species and ecosystems independently, though in reality, stressors often interact in ways that are not well understood. Here, we use a network interaction model (OSIRIS) to explicitly study stressor interactions in the Chukchi Sea (Arctic Ocean) due to its extensive climate-driven loss of sea ice and accelerated growth of other stressors, including shipping and oil exploration. The model includes numerous trophic levels ranging from phytoplankton to polar bears. We find that climate-related stressors have a larger impact on animal populations than do acute stressors like increased shipping and subsistence harvesting. In particular, organisms with a strong temperature-growth rate relationship show the greatest changes in biomass as interaction strength increased, but also exhibit the greatest variability. Neglecting interactions between stressors vastly underestimates the risk of population crashes. Our results indicate that models must account for stressor interactions to enable responsible management and decision-making.


Assuntos
Mudança Climática , Conservação dos Recursos Naturais/métodos , Ecossistema , Pesqueiros/estatística & dados numéricos , Peixes/fisiologia , Algoritmos , Animais , Regiões Árticas , Biomassa , Peixes/classificação , Camada de Gelo , Modelos Teóricos , Oceanos e Mares , Fitoplâncton/fisiologia , Temperatura , Ursidae/fisiologia
2.
Nat Commun ; 11(1): 6253, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-33288750

RESUMO

Domesticator-domesticate relationships are specialized mutualisms where one species provides multigenerational support to another in exchange for a resource or service, and through which both partners gain an advantage over individuals outside the relationship. While this ecological innovation has profoundly reshaped the world's landscapes and biodiversity, the ecological circumstances that facilitate domestication remain uncertain. Here, we show that longfin damselfish (Stegastes diencaeus) aggressively defend algae farms on which they feed, and this protective refuge selects a domesticator-domesticate relationship with planktonic mysid shrimps (Mysidium integrum). Mysids passively excrete nutrients onto farms, which is associated with enriched algal composition, and damselfish that host mysids exhibit better body condition compared to those without. Our results suggest that the refuge damselfish create as a byproduct of algal tending and the mutual habituation that damselfish and mysids exhibit towards one another were instrumental in subsequent mysid domestication. These results are consistent with domestication via the commensal pathway, by which many common examples of animal domestication are hypothesized to have evolved.


Assuntos
Domesticação , Ecossistema , Peixes/fisiologia , Invertebrados/fisiologia , Simbiose/fisiologia , Animais , Belize , Biodiversidade , Recifes de Corais , Peixes/classificação , Geografia , Invertebrados/classificação , Microalgas/classificação , Microalgas/fisiologia
3.
PLoS One ; 15(11): e0242017, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33170883

RESUMO

Offshore oil and gas platforms have a finite life of production operations. Once production ceases, decommissioning options for the platform are assessed. The role that a platform's jacket plays as fish habitat can inform the decommissioning decision. In this study, conducted along the crossbeams of a California platform jacket and using an ROV, we compared estimates of fish diversity and densities determined from a targeted "biological" survey with those from a replicated "structural" survey. We found that the water column fish species assemblages characterized by the two methods were similar. By contrast, the two survey methods yielded different species assemblages inhabiting the crossbeam at the platform jacket base. This difference occurred because, at least off California, the platform jacket base species diversity tends to be highest where the bottom crossbeam is undercut, creating sheltering sites for many species. Because the structural method inadequately imaged the seafloor-crossbeam interface, particularly where a gap occurred between crossbeam and seafloor, substantial numbers of fishes were not visible. While we cannot extrapolate from this study to all platforms' worldwide, it is clear that routine platform structural integrity surveys may be a valuable source for opportunistic marine community surveys. Intentional planning of the structural survey to incorporate relatively minor variations (e.g., maintaining fixed ROV distance from the infrastructure and consistent 90° camera angle) coupled with a deliberate consideration of the platform ecology (e.g., positioning the ROV to capture the seafloor-crossbeam interface) can substantially improve the effects on fish assemblage assessments from routine structural surveys without compromising the integrity assessment. We suggest that these biases should be both acknowledged and, understood when using routine structural surveys to inform platform ecology assessment. Additional consideration may be given to structural surveys that incorporate incremental adjustments to provide better data applicability to biological assessments.


Assuntos
Monitoramento Ambiental/métodos , Robótica/métodos , Animais , Biodiversidade , California , Ecossistema , Peixes/classificação , Campos de Petróleo e Gás , Densidade Demográfica , Inquéritos e Questionários/estatística & dados numéricos , Água
4.
PLoS One ; 15(11): e0240685, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33147227

RESUMO

Tectonic lakes are among the most geologically fascinating and environmentally versatile hydrobiological systems found on the earth's surface. We conducted a study on the limnology of Tasek Lake, a tectonic lake located in the Indo-Burma Province of the South Asian region. Physico-chemical parameters of the lake's water along with its plankton were considered for the study. Their relationship was analysed by understanding their seasonal variations and through linear regression models. The water quality index (WQI), plankton diversity indices and canonical correspondence analysis (CCA) were computed. The ichthyofaunal diversity was also studied to get an insight into the lake's fishery potential. A preliminary assessment on the economic feasibility of converting Tasek Lake into a fishery was also completed. Results indicate moderate eutrophication in the lake and the plankton population is observed to be rich and abundant. The WQI value confirms the water to be of "very poor" quality. The CCA was done to analyze the relationships of physico-chemical parameters with months and seasons, and the relation between seasons and plankton assemblages. Results corroborate the results of WQI. Identified fish population suggest ample fishery potential of the lake. The economic assessment reveals that in order to maintain the ecological sustainability of the lake, it should be transformed into a recreational fishery, following a catch-and-release model. The study calls for urgent restoration of the lake so that not only its pristine ecology is survived but also its fishery potential is sustainably harnessed and local livelihood is improved.


Assuntos
Biodiversidade , Pesqueiros/estatística & dados numéricos , Peixes/crescimento & desenvolvimento , Plâncton/crescimento & desenvolvimento , Qualidade da Água , Animais , Conservação dos Recursos Naturais/economia , Conservação dos Recursos Naturais/métodos , Conservação dos Recursos Naturais/estatística & dados numéricos , Ecossistema , Monitoramento Ambiental/economia , Monitoramento Ambiental/métodos , Monitoramento Ambiental/estatística & dados numéricos , Eutrofização , Peixes/classificação , Água Doce/análise , Geografia , Índia , Lagos , Mianmar , Plâncton/classificação , Estações do Ano
5.
PLoS One ; 15(11): e0236540, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33147221

RESUMO

The deep ocean is the largest biome on Earth and faces increasing anthropogenic pressures from climate change and commercial fisheries. Our ability to sustainably manage this expansive habitat is impeded by our poor understanding of its inhabitants and by the difficulties in surveying and monitoring these areas. Environmental DNA (eDNA) metabarcoding has great potential to improve our understanding of this region and to facilitate monitoring across a broad range of taxa. Here, we evaluate two eDNA sampling protocols and seven primer sets for elucidating fish diversity from deep sea water samples. We found that deep sea water samples (> 1400 m depth) had significantly lower DNA concentrations than surface or mid-depth samples necessitating a refined protocol with a larger sampling volume. We recovered significantly more DNA in large volume water samples (1.5 L) filtered at sea compared to small volume samples (250 mL) held for lab filtration. Furthermore, the number of unique sequences (exact sequence variants; ESVs) recovered per sample was higher in large volume samples. Since the number of ESVs recovered from large volume samples was less variable and consistently high, we recommend the larger volumes when sampling water from the deep ocean. We also identified three primer sets which detected the most fish taxa but recommend using multiple markers due the variability in detection probabilities and taxonomic resolution among fishes for each primer set. Overall, fish diversity results obtained from metabarcoding were comparable to conventional survey methods. While eDNA sampling and processing need be optimized for this unique environment, the results of this study demonstrate that eDNA metabarcoding can facilitate biodiversity surveys in the deep ocean, require less dedicated survey effort per unit identification, and are capable of simultaneously providing valuable information on other taxonomic groups.


Assuntos
Código de Barras de DNA Taxonômico/métodos , DNA Ambiental/análise , Peixes/classificação , Animais , Oceano Atlântico , Primers do DNA/genética , Monitoramento Ambiental , Peixes/genética , Filogenia , Análise de Sequência de DNA
6.
Rev Bras Parasitol Vet ; 29(4): e013520, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33053058

RESUMO

This study investigated the fauna of monogeneans on gills of 13 fish species from the Matapi River, Brazilian Amazon. A total 548 fish belonging to 13 species (1 Anostomidae, 3 Characidae, 1 Curimatidae, 1 Hemiodontidae, 2 Serrasalmidae, 3 Scianidae, 1 Ageneiosidae and 1 Tetradontidae) were examined. From these fish, 6 species were infected and with a total prevalence of 22.4%. Monogeneans collected are represented by the following taxa: Anacanthorus gravihamulatus, Notozothecium minor, Notozothecium penetrarum, Diplectanum piscinarius, Aetheolabes goeldiensis, Euryhaliotrema succedanus, Anacanthorus jegui, Urocleidoides astyanacis, Urocleidoides strombicirrus, Euryhaliotrema sp. and Urocleidoides spp. There was a variation in the prevalence, mean intensity and mean abundance of monogeneans among the host populations examined. Monogeneans of Metynnis lippincottianus, Plagioscion squamosissimus, Astyanax bimaculatus and Curimata incompta presented a highly aggregated dispersion pattern. Body weight of M. lippincottianus and C. incompta presented a weak positive correlation with abundance of parasites. Lastly, this is first study for 12 fish species from the Matapi River and the first report of E. succedanus for Plagioscion surinamensis and N. penetrarum for Serrasalmus rhombeus.


Assuntos
Doenças dos Peixes , Peixes/parasitologia , Brânquias/parasitologia , Parasitos/classificação , Trematódeos/classificação , Animais , Brasil , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/parasitologia , Peixes/classificação , Rios
7.
Sci Rep ; 10(1): 16081, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32999397

RESUMO

Pronounced organism-wide morphological stasis in evolution has resulted in taxa with unusually high numbers of primitive characters. These 'living fossils' hold a prominent role for our understanding of the diversification of the group in question. Here we provide the first detailed osteological analysis of Aenigmachanna gollum based on high-resolution nano-CT scans and one cleared and stained specimen of this recently described snakehead fish from subterranean waters of Kerala in South India. In addition to a number of derived and unique features, Aenigmachanna has several characters that exhibit putatively primitive conditions not encountered in the family Channidae. Our morphological analysis provides evidence for the phylogenetic position of Aenigmachanna as the sister group to Channidae. Molecular analyses further emphasize the uniqueness of Aenigmachanna and indicate that it is a separate lineage of snakeheads, estimated to have split from its sister group at least 34 or 109 million years ago depending on the fossil calibration employed. This may indicate that Aenigmachanna is a Gondwanan lineage, which has survived break-up of the supercontinent, with India separating from Africa at around 120 mya. The surprising morphological disparity of Aenigmachanna from members of the Channidae lead us to erect a new family of snakehead fishes, Aenigmachannidae, sister group to Channidae, to accommodate these unique snakehead fishes.


Assuntos
Peixes/classificação , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/genética , Evolução Biológica , DNA/genética , Evolução Molecular , Peixes/anatomia & histologia , Peixes/genética , Fósseis/anatomia & histologia , Fósseis/diagnóstico por imagem , História Antiga , Índia , Filogenia , Fatores de Tempo , Microtomografia por Raio-X/métodos
8.
PLoS One ; 15(10): e0231127, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33022692

RESUMO

Biodiversity is an important parameter for the evaluation of the extant environmental conditions. Here, we used environmental DNA (eDNA) metabarcoding to investigate fish biodiversity in five different estuaries in Japan. Water samples for eDNA were collected from river mouths and adjacent coastal areas of two estuaries with high degrees of development (the Tama and Miya Rivers) and three estuaries with relatively low degrees of development (the Aka, Takatsu, and Sendai Rivers). A total of 182 fish species across 67 families were detected. Among them, 11 species occurred in all the rivers studied. Rare fishes including endangered species were successfully detected in rich natural rivers. Biodiversity was the highest in the Sendai River and lowest in the Tama River, reflecting the degree of human development along each river. Even though nutrient concentration was low in both the Aka and Sendai Rivers, the latter exhibited greater diversity, including many tropical or subtropical species, owing to its more southern location. Species composition detected by eDNA varied among rivers, reflecting the distribution and migration of fishes. Our results are in accordance with the ecology of each fish species and environmental conditions of each river.


Assuntos
Código de Barras de DNA Taxonômico/métodos , DNA Ambiental/análise , Peixes/classificação , Animais , Biodiversidade , Monitoramento Ambiental/métodos , Estuários , Peixes/genética , Atividades Humanas , Japão , Filogenia , Rios
9.
Proc Natl Acad Sci U S A ; 117(40): 24876-24884, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32958671

RESUMO

Whereas the gill chambers of jawless vertebrates open directly into the environment, jawed vertebrates evolved skeletal appendages that drive oxygenated water unidirectionally over the gills. A major anatomical difference between the two jawed vertebrate lineages is the presence of a single large gill cover in bony fishes versus separate covers for each gill chamber in cartilaginous fishes. Here, we find that these divergent patterns correlate with the pharyngeal arch expression of Pou3f3 orthologs. We identify a deeply conserved Pou3f3 arch enhancer present in humans through sharks but undetectable in jawless fish. Minor differences between the bony and cartilaginous fish enhancers account for their restricted versus pan-arch expression patterns. In zebrafish, mutation of Pou3f3 or the conserved enhancer disrupts gill cover formation, whereas ectopic pan-arch Pou3f3b expression generates ectopic skeletal elements resembling the multimeric covers of cartilaginous fishes. Emergence of this Pou3f3 arch enhancer >430 Mya and subsequent modifications may thus have contributed to the acquisition and diversification of gill covers and respiratory strategies during gnathostome evolution.


Assuntos
Elementos Facilitadores Genéticos , Evolução Molecular , Brânquias/crescimento & desenvolvimento , Fatores do Domínio POU/genética , Vertebrados/genética , Animais , Peixes/classificação , Peixes/genética , Peixes/crescimento & desenvolvimento , Mutação , Filogenia , Tubarões/classificação , Tubarões/genética , Tubarões/crescimento & desenvolvimento , Vertebrados/classificação , Vertebrados/crescimento & desenvolvimento
10.
PLoS One ; 15(9): e0238767, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32898173

RESUMO

AIM: Exotic species' introductions together with extinction of native species represent the main mechanisms driving biotic homogenization of freshwater fish assemblages around the world. While generally ichtyofaunistic realms transit towards biotic homogenization, for conservation purposes it is essential to understand what specific mechanisms are promoting it on particular areas or regions. Here, we report the occurrence of biotic homogenization in 29 Chilean watersheds, analyzing its ß-diversity (including turnover and nestedness) and predicting future trends. LOCATION: Continental Chile (18o-56o S). METHODS: We determined fish composition per basin for historical and current assemblages; extant native, exotic, and extinct species were recorded as 1 (presence) or 0 (absence) in two matrices basins × species. For each matrix, we calculated the turnover (ßsim), nestedness (ßnes), and ß-diversity (ßsor); then, we obtained Δßsim, Δßnes, and Δßsor, as the arithmetical difference between basin pairs over time. In addition, we search for explanatory variables correlating Δßsim, Δßnes, and Δßsor with geographical and land use variables. Finally, simulating events of species introduction (i.e., invasion) and extinction, we generated 15 hypothetical assemblages, looking to establish future trends towards biotic change in Chilean basins. RESULTS: Species turnover and ß-diversity significantly decreased from historical to current assemblages (Δßsim = -0.084; Δßsor = -0.061, respectively), while the species nestedness did not show significant changes (Δßnes = 0.08). Biotic changes have been driven mainly by the introduction of 28 exotic species, with a minor role of extinctions (one species) and translocations (0 species) of native species. Changes in ß-diversity were negatively correlated with area, elevation, and geographical distance between basins but not with land-use nor human population. Finally, the analysis of 15 future assemblages predicts a significant decrease of ß-diversity and turnover, and an increase for species nestedness, this time promoted by an increase in the extinction of native species. MAIN CONCLUSION: Chilean basins show a significant decrease of the distributional ß-diversity and species turnover of the freshwater fish fauna, evidencing a trend towards biotic homogenization. This trend is shared with other Neotropical basins; however, specific mechanisms driving it show different magnitude. Changes in the ß-diversity components do not show correlation with variables associated to land use, thus suggesting that casual introductions of freshwater fishes in Chile follow an opportunistic mode related to commercial use. According to future scenarios simulated, biotic homogenization should increase further, mainly as consequence of increased native extinctions.


Assuntos
Biodiversidade , Extinção Biológica , Peixes/classificação , Água Doce , Espécies Introduzidas/estatística & dados numéricos , Animais , Chile
11.
Nat Commun ; 11(1): 4764, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958769

RESUMO

Industrial-scale harvest of species at risk of extinction is controversial and usually highly regulated on land and for charismatic marine animals (e.g. whales). In contrast, threatened marine fish species can be legally caught in industrial fisheries. To determine the magnitude and extent of this problem, we analyze global fisheries catch and import data and find reported catch records of 91 globally threatened species. Thirteen of the species are traded internationally and predominantly consumed in European nations. Targeted industrial fishing for 73 of the threatened species accounts for nearly all (99%) of the threatened species catch volume and value. Our results are a conservative estimate of threatened species catch and trade because we only consider species-level data, excluding group records such as 'sharks and rays.' Given the development of new fisheries monitoring technologies and the current push for stronger international mechanisms for biodiversity management, industrial fishing of threatened fish and invertebrates should no longer be neglected in conservation and sustainability commitments.


Assuntos
Espécies em Perigo de Extinção/estatística & dados numéricos , Pesqueiros/estatística & dados numéricos , Peixes , Invertebrados , Animais , Biodiversidade , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção/economia , Pesqueiros/economia , Peixes/classificação , Invertebrados/classificação , Biologia Marinha , Alimentos Marinhos/classificação , Alimentos Marinhos/economia , Alimentos Marinhos/estatística & dados numéricos
12.
Science ; 369(6511): 1608-1615, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32732279

RESUMO

Sexual parasitism has evolved as a distinctive mode of reproduction among deep-sea anglerfishes. The permanent attachment of males to host females observed in these species represents a form of anatomical joining, which is otherwise unknown in nature. Pronounced modifications to immune facilities are associated with this reproductive trait. The genomes of species with temporarily attaching males lack functional aicda genes that underpin affinity maturation of antibodies. Permanent attachment is associated with additional alterations, culminating in the loss of functional rag genes in some species, abolishing somatic diversification of antigen receptor genes, the hallmark of canonical adaptive immunity. In anglerfishes, coevolution of innate and adaptive immunity has been disentangled, implying that an alternative form of immunity supported the emergence of this evolutionarily successful group of vertebrates.


Assuntos
Peixes/genética , Peixes/imunologia , Interações Hospedeiro-Parasita/genética , Interações Hospedeiro-Parasita/imunologia , Comportamento Sexual Animal , Imunidade Adaptativa/genética , Animais , Anticorpos/genética , Afinidade de Anticorpos/genética , Coevolução Biológica , Citidina Desaminase/genética , Feminino , Peixes/classificação , Variação Genética , Imunidade Inata/genética , Imunogenética , Complexo Principal de Histocompatibilidade/genética , Masculino , Filogenia , Receptores de Antígenos , Reprodução/genética , Reprodução/imunologia
13.
Nat Commun ; 11(1): 3832, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737315

RESUMO

Tropical ectotherms are hypothesized to be vulnerable to environmental changes, but cascading effects of organismal tolerances on the assembly and functioning of reef fish communities are largely unknown. Here, we examine differences in organismal traits, assemblage structure, and productivity of cryptobenthic reef fishes between the world's hottest, most extreme coral reefs in the southern Arabian Gulf and the nearby, but more environmentally benign, Gulf of Oman. We show that assemblages in the Arabian Gulf are half as diverse and less than 25% as abundant as in the Gulf of Oman, despite comparable benthic composition and live coral cover. This pattern appears to be driven by energetic deficiencies caused by responses to environmental extremes and distinct prey resource availability rather than absolute thermal tolerances. As a consequence, production, transfer, and replenishment of biomass through cryptobenthic fish assemblages is greatly reduced on Earth's hottest coral reefs. Extreme environmental conditions, as predicted for the end of the 21st century, could thus disrupt the community structure and productivity of a critical functional group, independent of live coral loss.


Assuntos
Antozoários/fisiologia , Biodiversidade , Peixes/fisiologia , Modelos Estatísticos , Adaptação Fisiológica , Animais , Biomassa , Recifes de Corais , Planeta Terra , Ecossistema , Peixes/classificação , Cadeia Alimentar , Temperatura Alta , Oriente Médio , Oceanos e Mares
14.
Parasitol Res ; 119(10): 3285-3296, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32812144

RESUMO

The taxonomy of Hysterothylacium genus in Mediterranean waters remains incomplete and unresolved. The aim of the current study was to investigate the morphological and molecular identification of selected species of Hysterothylacium larvae in marine fish from the Tunisian Mediterranean coasts. A total of 192 marine fish samples were examined. In total, thirty-seven third-stage larvae of Hysterothylacium were morphologically identified as Hysterothylacium type V. In the present study, representatives of this type from the Mediterranean Sea were genetically characterized for the first time by sequencing the rDNA ITS (ITS1-5.8S-ITS2) regions and mtDNA cox2 gene. This study represents the first report of Hysterothylacium type V from the Mediterranean Sea. We also report Mullus barbatus, M. surmuletus, and Pagellus erythrinus as new hosts for this larval type. Based upon molecular and phylogenetic analyses considering the rDNA ITS regions, the Hysterothylacium type V described here was classified as a new genotype, named Genotype B. The valid genetic data of the described Hysterothylacium type V in the present study can be used to establish the phylogenetic relationships among Hysterothylacium species from the Mediterranean Sea and worldwide for future research.


Assuntos
Infecções por Ascaridida/veterinária , Ascaridoidea/classificação , Ascaridoidea/crescimento & desenvolvimento , Doenças dos Peixes/parasitologia , Peixes/parasitologia , Animais , Infecções por Ascaridida/parasitologia , Ascaridoidea/anatomia & histologia , Ascaridoidea/genética , DNA Mitocondrial/genética , DNA Espaçador Ribossômico/genética , Peixes/classificação , Genes de Helmintos/genética , Genótipo , Larva/anatomia & histologia , Larva/classificação , Larva/genética , Larva/crescimento & desenvolvimento , Mar Mediterrâneo , Filogenia
15.
Nat Commun ; 11(1): 4155, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32814776

RESUMO

Declines in animal body sizes are widely reported and likely impact ecological interactions and ecosystem services. For harvested species subject to multiple stressors, limited understanding of the causes and consequences of size declines impedes prediction, prevention, and mitigation. We highlight widespread declines in Pacific salmon size based on 60 years of measurements from 12.5 million fish across Alaska, the last largely pristine North American salmon-producing region. Declines in salmon size, primarily resulting from shifting age structure, are associated with climate and competition at sea. Compared to salmon maturing before 1990, the reduced size of adult salmon after 2010 has potentially resulted in substantial losses to ecosystems and people; for Chinook salmon we estimated average per-fish reductions in egg production (-16%), nutrient transport (-28%), fisheries value (-21%), and meals for rural people (-26%). Downsizing of organisms is a global concern, and current trends may pose substantial risks for nature and people.


Assuntos
Tamanho Corporal , Ecossistema , Pesqueiros/estatística & dados numéricos , Salmão/crescimento & desenvolvimento , Fatores Etários , Alaska , Animais , Clima , Mudança Climática , Peixes/classificação , Peixes/crescimento & desenvolvimento , Geografia , Dinâmica Populacional , Fatores de Risco , Salmão/classificação , Especificidade da Espécie
16.
Sci Data ; 7(1): 229, 2020 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-32661270

RESUMO

Estuaries are crucial ecosystems where human activities deeply affect numerous ecological functions. Here we present a survey dataset based on the monitoring of fish nursery grounds of the Seine estuary and eastern bay of Seine collected once a year using a beam trawl during three distinct periods (1995-2002, 2008-2010 and 2017-2019). The surveys happen at the start of autumn in order to maximize the catchability of juvenile fish. The beam trawl mainly targets benthic and demersal species on a study area that extends over 600 square kilometers. The dataset includes abundance and densities of 161 species for 634 hauls performed around 40 stations each year. These data can be used by fishery scientists and ecologists motivated by early life stages of commercial species or by the impact of human disturbances, such as harbor developments, on estuarine communities.


Assuntos
Estuários , Pesqueiros , Peixes/classificação , Animais , França
17.
Sci Rep ; 10(1): 12479, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32719358

RESUMO

The arrangement and composition of habitats within landscapes and fine-scale habitat characteristics influence community structure and ecological processes. These aspects can be altered by anthropogenic activities, thus influencing associated assemblages. Farming of macroalgae is a common practice in tropical settings and alters the natural composition of seascapes by introducing monoculture patches. The farmed macroalgae may also differ in palatability compared to naturally-occurring macroalgae, influencing herbivory. This study assessed how these farms may differ from natural macroalgal beds in terms of habitat heterogeneity, fish assemblages, and herbivory. We surveyed fish assemblages and deployed macroalgal assays within macroalgal beds, farms and at varying distances from these habitats near Mafia Island, Tanzania. Fish composition and herbivory differed between the habitats likely due to different macrophyte species richness, underlying hard substrate in natural macroalgal beds, and high abundance of browsers nearby the farms. Additionally, fish assemblage patterns and herbivory were not consistent across the seascapes and varied with distance from the focal habitats possibly due to the presence of other habitats. The results suggest alterations of seascapes by farming practices may have consequences on fish assemblages and the ecological functions performed, thus positioning of farms should be carefully considered in management and conservation plans.


Assuntos
Ecossistema , Peixes/classificação , Animais , Peixes/genética , Peixes/crescimento & desenvolvimento , Oceano Índico , Alga Marinha/crescimento & desenvolvimento , Tanzânia
18.
Sci Rep ; 10(1): 12683, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32728037

RESUMO

Connectivity and local adaptation are two contrasting evolutionary forces highly influencing population structure. To evaluate the impact of early-life traits and environmental conditions on genetic structuring and adaptation, we studied two sympatric fish species in the Western Mediterranean Sea: Symphodus tinca and S. ocellatus. We followed an individual-based approach and measured early-life history traits from otolith readings, gathered information on environmental variables and obtained genome-wide markers from genotyping-by-sequencing (GBS). The two species presented contrasting population structure across the same geographic gradient, with high and significant population differentiation in S. ocellatus, mostly determined by oceanographic fronts, and low differentiation and no front effect in S. tinca. Despite their different levels of genetic differentiation, we identified in both species candidate regions for local adaptation by combining outlier analysis with environmental and phenotypic association analyses. Most candidate loci were associated to temperature and productivity in S. ocellatus and to temperature and turbulence in S. tinca suggesting that different drivers may determine genomic diversity and differentiation in each species. Globally, our study highlights that individual-based approach combining genomic, environmental and phenotypic information is key to identify signals of selection and the processes mediating them.


Assuntos
Peixes/fisiologia , Genômica/métodos , Animais , Animais Congênicos , Evolução Biológica , Peixes/classificação , Peixes/genética , Traços de História de Vida , Análise de Sequência de DNA , Especificidade da Espécie , Simpatria
19.
PLoS One ; 15(7): e0236575, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32722713

RESUMO

Diadromous fishes have drastically declined over the last century, especially in Europe. Several authors have highlighted the role of large dams in this decline, but in fact, its causes are potentially multiple and cumulative, including degradation of local environmental conditions and widespread fragmentation of hydrographic networks associated with the pervasive establishment of smaller barriers. Consequently, there is a need to improve the identification and prioritization of the drivers of diadromous species loss in order to identify and apply the most appropriate conservation and restoration measures. In this study, we used both historical sources (from mid-18th to early 20th century) and current data to quantify the long-term loss of diadromous taxa over 555 sites throughout the French river network. Then, we modeled the effects of several anthropogenic pressures (e.g. barriers, water quality, hydrological and river morphological alterations) on diadromous taxon loss. Lastly, we assessed the potential consequences of four different scenarios of anthropogenic pressure reduction. Due to uncertainties in historical sources, some species were grouped into taxa leading to a potential underestimation of actual species extinctions. Despite this limitation, our results showed that the decline in diadromous assemblages is widespread but with contrasting magnitudes depending on site locations. The maximum height and density of barriers appeared as the major factors of taxon loss. Over the scenarios tested, we observed that exclusively improving local conditions have much more limited effects than restoring river continuity. Focusing actions on large dam removal did not show the strongest responses compared to removing medium and small-sized barriers. For effective and sustainable restoration of diadromous fish assemblage, (1) historical occurrences of diadromous fishes should be used as an indicator for assessing recovery, and (2) undertaken measures must be adapted to each basin to target and limit the number of barriers to remove while allowing diadromous fish recovery.


Assuntos
Migração Animal , Monitoramento Ambiental , Peixes , Modelos Estatísticos , Rios , Animais , Biodiversidade , Peixes/classificação , Atividades Humanas , Hidrologia , Dinâmica Populacional , Qualidade da Água
20.
Science ; 369(6499): 65-70, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32631888

RESUMO

Species' vulnerability to climate change depends on the most temperature-sensitive life stages, but for major animal groups such as fish, life cycle bottlenecks are often not clearly defined. We used observational, experimental, and phylogenetic data to assess stage-specific thermal tolerance metrics for 694 marine and freshwater fish species from all climate zones. Our analysis shows that spawning adults and embryos consistently have narrower tolerance ranges than larvae and nonreproductive adults and are most vulnerable to climate warming. The sequence of stage-specific thermal tolerance corresponds with the oxygen-limitation hypothesis, suggesting a mechanistic link between ontogenetic changes in cardiorespiratory (aerobic) capacity and tolerance to temperature extremes. A logarithmic inverse correlation between the temperature dependence of physiological rates (development and oxygen consumption) and thermal tolerance range is proposed to reflect a fundamental, energetic trade-off in thermal adaptation. Scenario-based climate projections considering the most critical life stages (spawners and embryos) clearly identify the temperature requirements for reproduction as a critical bottleneck in the life cycle of fish. By 2100, depending on the Shared Socioeconomic Pathway (SSP) scenario followed, the percentages of species potentially affected by water temperatures exceeding their tolerance limit for reproduction range from ~10% (SSP 1-1.9) to ~60% (SSP 5-8.5). Efforts to meet ambitious climate targets (SSP 1-1.9) could therefore benefit many fish species and people who depend on healthy fish stocks.


Assuntos
Aclimatação , Mudança Climática , Peixes/crescimento & desenvolvimento , Estágios do Ciclo de Vida , Animais , Peixes/classificação , Temperatura Alta , Oxigênio/metabolismo , Consumo de Oxigênio , Filogenia
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