Ecological roles and importance of sharks in the Anthropocene Ocean

Science, Journal Year: 2024, Volume and Issue: 385(6708)

Published: Aug. 1, 2024

In ecosystems, sharks can be predators, competitors, facilitators, nutrient transporters, and food. However, overfishing other threats have greatly reduced shark populations, altering their roles effects on ecosystems. We review these changes implications for ecosystem function management. Macropredatory are often disproportionately affected by humans but influence prey coastal including facilitating carbon sequestration. Like terrestrial may crucial to functioning under climate change. large of not ubiquitous. Increasing human uses oceans changing roles, necessitating management consideration. Rebuilding key populations incorporating ecological less obvious ones, into efforts critical retaining sharks' functional value. Coupled social-ecological frameworks facilitate efforts.

Language: Английский

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Phylogenetic analysis of viviparity, matrotrophy, and other reproductive patterns in chondrichthyan fishes

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2024, Volume and Issue: 99(4), P. 1314 - 1356

Published: April 1, 2024

ABSTRACT The reproductive diversity of extant cartilaginous fishes (class Chondrichthyes) is extraordinarily broad, reflecting more than 400 million years evolutionary history. Among their many notable specialisations are viviparity (live‐bearing reproduction) and matrotrophy (maternal provision nutrients during gestation). However, attempts to understand the evolution these traits have yielded highly discrepant conclusions. Here, we compile analyse current knowledge on in Chondrichthyes with particular foci frequency, phylogenetic distribution, directionality changes modes reproduction. To characterise transformations, amassed largest empirical data set parameters date covering nearly 800 species analysed it via a comprehensive molecular‐based phylogeny. Our reconstructions indicated that ancestral pattern for ‘short single oviparity’ (as found holocephalans) which females lay successive clutches (broods) one or two eggs. Viviparity has originated at least 12 times, 10 origins among sharks, batoids, (based published evidence) another potential origin fossil holocephalan. Substantial evolved six including placentotrophy, three separate oophagy (egg ingestion), histotrophy (uptake uterine secretions). In clades, placentation was replaced by histotrophy. Unlike past reconstructions, our analysis reveals no evidence ever reverted oviparity this group. Both arisen variety sequences. addition, given rise distinct egg‐laying patterns increased clutch (brood) size and/or involved deposition eggs advanced stages development. Geologically, oviparous arose Paleozoic. Most Mesozoic, while few represented low taxonomic levels Cenozoic origin. Coupled other recent work, review points way towards an emerging consensus chondrichthyans offering basis future functional analyses. This also contributes conservation efforts highlighting taxa whose reflect distinctive trajectories deserve special protection further investigation.

Language: Английский

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Sharks in Macaronesia and Cabo Verde: species richness, conservation status and anthropogenic pressures

Frontiers in Marine Science, Journal Year: 2025, Volume and Issue: 12

Published: Feb. 5, 2025

The northeast Atlantic Ocean contains multiple habitats considered critical for shark conservation, including nursery areas, migratory corridors and aggregation sites. In this context, updating knowledge on diversity the threats affecting them in region is essential to defining priorities implementing right management conservation measures. Here, we show that Macaronesian Cabo Verde marine ecoregions are home 78 species (comprising 26 families), 56% threatened with extinction. Canary Islands revealed greatest richness (with 56 species), followed by (53), Madeira (52), Azores (45). presents fewer similarities rest of islands. We also found that: i) share more than (despite greater geographical proximity latter), ii) there no oviparous archipelago, contrary (5), (4), (3). Fishing habitat degradation most relevant anthropogenic pressures region, having highest number endangered (66%) a magnitude threats. As such, archipelago priority area due intense industrial fishing its waters, poor measures combination vulnerability climate change.

Language: Английский

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Ecological erosion and expanding extinction risk of sharks and rays

Science, Journal Year: 2024, Volume and Issue: 386(6726)

Published: Dec. 5, 2024

The true state of ocean biodiversity is difficult to assess, and there are few global indicators track the primary threat overfishing. We calculated a 50-year Red List Index extinction risk ecological function for 1199 sharks rays found that since 1970, overfishing has halved their populations worsened by 19%. Overfishing largest species in nearshore pelagic habitats risks loss ecomorphotypes 5 22% erosion functional diversity. Extinction higher countries with large human coastal but lower nations stronger governance, larger economies, greater beneficial fisheries subsidies. Restricting fishing (including incidental catch) trade sustainable levels combined prohibiting retention highly threatened can avert further depletion, widespread population connectivity, top-down predator control.

Language: Английский

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Sequential trait evolution did not drive deep-time diversification in sharks

Evolution, Journal Year: 2024, Volume and Issue: 78(8), P. 1405 - 1425

Published: May 15, 2024

Estimating how traits evolved and impacted diversification across the tree of life represents a critical topic in ecology evolution. Although there has been considerable research comparative biology, large parts remain underexplored. Sharks are an iconic clade marine vertebrates, key components ecosystems since early Mesozoic. However, few studies have addressed or whether they their extant diversity patterns. Our study aimed to fill this gap by reconstructing largest time-calibrated species-level phylogeny sharks compiling exhaustive database for ecological (diet, habitat) biological (reproduction, maximum body length) traits. Using state-of-the-art models evolution diversification, we outlined major character shifts modes trait shark species. We found support sequential estimated small medium-sized lecithotrophic coastal-dwelling most recent common ancestor sharks. our hidden analyses do not trait-dependent any examined traits, challenging previous works. This suggests that role shaping sharks' dynamics might previously overestimated should motivate future macroevolutionary investigate other drivers clade.

Language: Английский

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Presence and Potential Effects of Microplastics in the Digestive Tract of Two Small Species of Shark from the Balearic Islands

Fishes, Journal Year: 2024, Volume and Issue: 9(2), P. 55 - 55

Published: Jan. 29, 2024

In recent years, there has been an increase in the reporting of plastic pollution marine environment and its effects on animals, especially bony fish. However, prevalence effect, particularly concerning biomarkers oxidative stress, elasmobranchs remain underreported unknown. this study, microplastics were observed two elasmobranch species from Balearic Islands: small-spotted catshark (Scyliorhinus canicula) with average 4.38 ± 1.77 items per individual, blackmouth (Galeus melastomus) 8.31 2.46 individual. Moreover, for first time, antioxidant pro-inflammatory responses determined digestive tract individuals both species. Specifically, activation defences, mainly superoxide dismutase activity glutathione levels, was observed, while marker myeloperoxidase also greater a high abundance microplastic items. Additionally, significant S-transferase catsharks ingestion evidenced, suggesting that detoxification process activated. Overall, results study highlight are ingesting microplastics, which, turn, causing physiological at cellular level. Considering this, continued monitoring these should include presence can serve as baseline data future research.

Language: Английский

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Long term declines in the functional diversity of sharks in the coastal oceans of eastern Australia

Communications Biology, Journal Year: 2024, Volume and Issue: 7(1)

Published: May 21, 2024

Abstract Human impacts lead to widespread changes in the abundance, diversity and traits of shark assemblages, altering functioning coastal ecosystems. The functional consequences declines are often poorly understood due absence empirical data describing long-term change. We use from Queensland Shark Control Program eastern Australia, which has deployed mesh nets baited hooks across 80 beaches using standardised methodologies since 1962. illustrate consistent richness quantified both ecological (e.g., feeding, habitat movement) morphological size, morphology) traits, this corresponds with declining functioning. demonstrate a community shift targeted apex sharks greater non-target species. Declines corresponding species may an anthropogenically induced trophic cascade. suggest that repairing diminished populations is crucial for stability

Language: Английский

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Biotic homogenization and functional restructuring of bee communities in northern France: implications for conservation priorities

Biodiversity and Conservation, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 7, 2025

Language: Английский

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How low-abundance amphibians shape functional diversity across tropical forest succession stages?

Ecological Indicators, Journal Year: 2025, Volume and Issue: 171, P. 113140 - 113140

Published: Jan. 29, 2025

Language: Английский

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The rise and fall of shark functional diversity over the last 66 million years

Global Ecology and Biogeography, Journal Year: 2024, Volume and Issue: 33(9)

Published: June 11, 2024

Abstract Aim Modern sharks are a diverse and highly threatened group playing important roles in ecosystems. They have an abundant fossil record spanning at least 250 million years (Myr), consisting primarily of isolated teeth. Throughout their evolutionary history, faced multiple environmental changes extinction events. Here, we aim to use dental characters quantify how shark functional diversity has changed during the last 66 Myr. Location Global. Time period Cenozoic era (66–0 ago; Ma). Major taxa studied Sharks (Selachii). Methods We complied dataset over 9000 teeth belonging 537 from museum collections scientific literature measured six strongly linked with traits. then quantified different metrics across time bins, compared them against null expectations identified most contributing maintaining diversity. Results displayed relatively high Cenozoic, 66%–87% space being occupied for ~60 Myr (Palaeocene Miocene). High levels redundancy this resulted larger‐than‐expected richness; but large decline (−45%) Oligocene (~30 Ma) left vulnerable further loss. Shark declined late Miocene (~10 onwards, losing 44% richness by Recent. Extinct disproportionally contributed spanned wider range than extant sharks, loss mid‐sized suction feeders large‐bodied predators driving declines. Main conclusions After lost nearly half ~10 Current anthropogenic pressures therefore likely eroding already diminished diversity, leaving future communities ecologically deprived thriving geological past.

Language: Английский

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