Basking sharks of the Arctic Circle: year-long, high-resolution tracking data reveal wide thermal range and prey-driven vertical movements across habitats

Animal Biotelemetry, Год журнала: 2025, Номер 13(1)

Опубликована: Май 9, 2025

Abstract Background Understanding the movement ecology of marine megaplanktivores is essential for conserving these ecologically significant species and managing their responses to environmental change. While telemetry has advanced our knowledge filter-feeding mammal migrations, annual patterns large sharks, such as basking sharks ( Cetorhinus maximus ), remain poorly understood. This particularly case near high latitude range limits where climate impacts are intensifying. In this study, we deployed pop-up satellite archival tags (PSATs) on C. in northern Norway investigate individual possible drivers over an entire cycle. Results Geolocated tracks from two females revealed contrasting migration strategies: one shark performed a return spending boreal winter close Azores, while other resided north Arctic Circle until January before moving North Sea spring. Across diverse habitats, both utilized wide thermal range. included previously unrecorded short-term exposures sub-zero temperatures, extending known tolerance species. High-resolution time series data recovered PSATs enabled use signal processing gradient-based filtering techniques vertical relation physical biological environment. oceanic elevated mesopelagic was observed together with diel migration, whereas shelf areas depth-use were confined by topography more variable, reflective dynamic hydrographic conditions prey distributions. With zooplankton distributions being structured ambient light, density gradients, local topography, alignment frequented depths isolumes, mixed layer depths, bathymetric contours, bioluminescence events suggests actively track layers across habitats. Conclusions Recorded eurythermy behavioural plasticity suggest be well-adapted ocean conditions. These traits may critical responding rapid climate-driven changes abiotic biotic environments high-latitudes, providing insights into how endangered filter-feeders might navigate shifting ecosystems. Graphical

Язык: Английский

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The Spatial Distribution Dynamics of Shark Bycatch by the Longline Fishery in the Western and Central Pacific Ocean

Journal of Marine Science and Engineering, Год журнала: 2025, Номер 13(2), С. 315 - 315

Опубликована: Фев. 8, 2025

Shark bycatch represents a substantial issue in the management of oceanic fisheries. Utilizing data on shark from longline fishery, as released by Western and Central Pacific Fisheries Commission, this study applied boosted regression tree model to examine impact environmental factors per unit effort (BPUE) key species, well predict spatial distribution dynamics both BPUE risk (BR). The findings emphasize that oxygen concentration, sea surface temperature, chlorophyll-a concentration are paramount sharks’ BPUE. Furthermore, compared variations preferences across diverse pinpointing attributes defining ecological niches distinct populations. predictions identified hotspots BR for bigeye thresher (Alopias superciliosus), longfin mako (Isurus paucus), silky (Carcharhinus falciformis), whitetip longimanus) tropical latitudes (10° S 15° N), blue (Prionace glauca) shortfin oxyrinchus) temperate zones (south 30° or north N). geometric center analysis indicated all species exhibited large annual fluctuations BR, most populations displayed significant shifting trends. Several grids (5° × 5°) were high-risk areas due their considerable contribution bycatch. centers observed shift eastward towards equatorial waters, This underscores necessity considering beyond when identifying critical implementation area-specific mitigation measures. insights derived can enhance support development enforcement targeted area-based fishery initiatives.

Язык: Английский

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Do Whale Sharks Select for Specific Environments to Give Birth?

Ecology and Evolution, Год журнала: 2025, Номер 15(2)

Опубликована: Фев. 1, 2025

ABSTRACT Neonate whale sharks < 1.5 m in length are rarely encountered, with approximately 35 sightings recorded globally between 1970 and 2020. Although potentially pregnant females seem to frequent certain sites, parturition areas unknown, most neonates have been sighted opportunistically offshore environments, suggesting nursery habitat may occur remote parts of the ocean. Here, documented accounts neonate corresponding locations were mapped relation oceanography identify whether there commonalities where they occur. Results show that coincide permanent oxygen minimum zones (OMZs)—with associated high surface chlorophyll‐a (Chl‐a) low at depth—more often than would be expected by random chance. Two main hypotheses proposed explain this apparent association: (i) adult female selectively pup waters adjacent regions offering a proximate refuge from oceanic predators as well enhanced foraging opportunities, or (ii) pupping occurs randomly open ocean but OMZs restrict shallower more frequently encountered humans elsewhere. Testing both requires data on relationship shark movement ecology dissolved concentrations. As first step, model predicts highest likelihood occurring above OMZs, focussed around intermediate Chl‐a boundaries highly productive upwelling systems. These could focus future, targeted studies. biologging devices measuring situ concentrations will useful for exploring how different life stages interact which expanding due climate‐driven deoxygenation. What might mean conservation future warmer oceans remains an question.

Язык: Английский

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Salinity drives the distribution of a top-order predator, the tiger shark (Galeocerdo cuvier), in an inverse estuary

Scientific Reports, Год журнала: 2025, Номер 15(1)

Опубликована: Март 25, 2025

Understanding how dynamic environmental processes influence the distributions of top-order predators is fundamental to assess top-down effects on ecosystems. Tiger sharks (Galeocerdo cuvier) are a large top-predator that can trigger trophic cascades and structure communities. However, physical these animals in coastal systems largely unknown. Here, we influencing tiger shark movements inverse estuary Shark Bay, Western Australia, shallow embayment with salinities consistently above adjacent ocean. We applied Bayesian generalized linear mixed-effects models generate predictions suitable habitat for this region. These habitats were associated dense seagrass beds reflected spatial variability hypersaline water (< 40). Under future climate scenarios, areas worldwide predicted experience estuarine conditions. anticipate study will become applicable numerous other species gill-breathing fauna ecosystems across globe.

Язык: Английский

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Seasonal dynamics of microbial communities link to summer-autumn aquaculture disease outbreaks in Sanggou Bay

Frontiers in Marine Science, Год журнала: 2025, Номер 12

Опубликована: Май 21, 2025

Marine microorganisms play a vital role in aquaculture by influencing water quality and the health of cultured species. Relative to conventional mono-species aquaculture, integrated multi-trophic is more environmentally friendly economically sustainable. However, temporospatial dynamics microbial community different modes their roles seasonal diseases aquacultural organisms are largely unknown. Here, seawater bacterial communities potential pathogens were investigated over thirteen months three types Sanggou Bay, typical maricultural area with nearly 60 years history. Seasonality played primary role, while type subtle shaping bacterioplankton community. Diverse identified, r -strategist bacteria, most which opportunistic typified Vibrio species, increased dominated late summer autumn, period high-risk disease outbreaks mariculture organisms. Network analyses indicated that increase bacteria reduced complexity interactions, halioticoli (OTU1389), hub species extensive positive correlations other OTUs, likely contributed pathogenic vibrios due its macroalgae degradation capability. The major OTUs further corroborated genome environmental simulation experiments using isolates, including two new Moreover, we found dissolved oxygen, temperature, transparency correlated significantly pathogens. Our results emphasize necessity synchronically monitoring community, pathogens-stimulating such as V. macroalgae-degrading critical physicochemical parameters for predicting preventing pathogen mariculture.

Язык: Английский

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Fish habitat ecology in a changing climate

Journal of Fish Biology, Год журнала: 2024, Номер 105(2), С. 385 - 391

Опубликована: Авг. 1, 2024

Understanding the factors driving fish behavior, physiology, and survival is increasingly important during this period of unprecedented global change, given their implications for fisheries stability ecosystem health. Habitat quality quantity shape population dynamics eco-evolutionary trajectories. Quantifying habitat needs across all life stages (and predators prey) challenging, however, relies on diverse approaches such as field observations, laboratory experiments, genomics, chemical tracers, telemetry, modeling. Successful integration these data into management policy requires open constructive knowledge exchange between natural social scientists, stakeholders, managers, policymakers, new tools to analyse visualize complex datasets. Building social-ecological connectivity particularly in dynamic boundary systems (e.g., estuaries) protecting species characterized by trans-boundary movements rivers seas, or jurisdictional borders) if we are maximize benefits nature humans alike. Here, present a collection papers that deal with topics Special Issue born from Fisheries Society British Isles (FSBI) 2023 Symposium, "Fish Ecology Changing Climate" (see Figure 1), held at University Essex co-convened Centre Environment, Aquaculture Science (Cefas). The overarching theme was inspired previous Jack Jones Lecture Jonathan Rice, "Understanding ecology achieve conservation" (Rice, 2005), where he argues "habitat science can provide unifying concepts bring together ecological studies physiological tolerances, predator avoidance, foraging feeding, reproduction histories." broaden definition include downstream effects loss restoration) services human food supply nutrient requirements, how habitats interact space management. FSBI Symposium fall under five major themes, which have clear links UN Sustainable Development Goals Climate Action, Life Below Water), critical roles 2). populations first an appreciation they not static entities move different could key resources shelter seasons stages. movement (Theme 1) thus empirical analytical challenge be overcome. Fish also do exist isolation, so managing target stock understanding changes ecosystems, prey, may underpin unexpected declines interest. role webs 2) therefore essential more holistic ecosystem-based approach. Integrating single-species responses changing conditions movement, connectivity, wider web will increase our capacity predicting future distributions 3). Anticipating help inform sounder habitats, only sustainable harvesting development contemporary but safeguarding health ecosystems. This integrated approach reveal importance restoring support stage crucial resource act bottlenecks persistence climate. Therefore, integrating Themes 1–3 provides comprehensive template restoration 4). Optimizing conservation commercially valuable stocks surrounding ecosystems ultimately benefit aquatic environments (through provisioning regulating provide) socioeconomics (via many jobs support). Thus, quantifying, predicting, climate change central recognizing preserving objectives "One Health" 5), is, optimizing people, animals, environment. Aquatic intrinsically connected flow water carries genes, organisms, waste products them (Keeley et al., 2022). functional maintaining genetic trophic among patches promoting resilience disturbance; it rarely incorporated marine spatial planning (Cowen 2007; Darnaude 2024). partly because bodies span countries even continents, frequently managed national regional level. Although river flows ocean currents play areas, swim countercurrent, creating multidirectional linkages multiple spatiotemporal scales (Cavan 2019; Flecker 2010). Indeed, perform energetically costly migrations fitness, often seasonally feeding spawning areas and/or ontogenetically nursery adult stock, visualized classic migration triangle (Harden Jones, 1968). These cross boundaries, challenges monitoring (Hermoso 2021; Speed Furthermore, migratory been heavily impacted fragmentation degradation, overexploitation, resulting widespread declines, those spend least part cycle fresh (Deinet 2020). In Issue, Franklin al. (2024) review expected affect structural discussing predicted distribution shifts response warming, hypoxia, other stressors. They outline solutions nature-positive adaptation, strategic planning, defining shifting baseline, adaptive management, performing relevant detect through time. although intraspecific biodiversity—such expression contingents within (Secor 2020)—underpins resilience, genotypic phenotypic traits monitored, being cited "hidden biodiversity crisis" (Des Roches 2021). Willmes (2024), frequency strategies Chinook salmon California described over 10-year period, both juvenile results highlight connections upstream well higher life-history diversity than despite century anthropogenic study shows climate-associated variation behavior growth should accounted when setting single baseline. Tracking settings remains ongoing challenge, increasing numbers demonstrating combining methods (otolith markers, biophysical modeling, tagging) assessing realms Brophy 2020; Michalsen 2014; growth, phenology any inherently dependent structure productivity web. imperative consider interactions complete respond change. For example, larger widely unfavored warmer (Baudron Eskuche-Keith 2024; see Audzijonyte 2020) due metabolic demands inefficient transfer energy longer chains (Barneche Brown 2004). However, size abundance actually temperature there sufficient primary greater biomasses helping overcome energetic constraints (Binzer 2012; O'Gorman 2017). Conversely, stronger warming lead simpler fewer intermediate otherwise persist face (O'Gorman 2023; Svensson bottom-up top-down control determining individual tolerate thrive conditions. Thorpe identify current limitation predictive research, whereby zooplankton poorly represented models though intermediary production communities. show sensitive treatment scenario 2°C, illustrating accurately capturing forecasting transcend Massie showing freshwater subsidies estuarine low levels body condition prized game fish. Such improve decisions aimed conserving ecologically socioeconomically species. ability forage along salinity gradient some increases inundation coastal estuaries (MacRae Recognizing one thing, incorporating biomonitoring has impeded difficulty time-consuming documenting plasticity environmental Rapid advances DNA metabarcoding could, bridge toward research (Canals rapid develop quantitative stages, biotic abiotic abundance. Using relationships, better parameterize forecast alternative scenarios. Warming, stressors faced linked large-scale latitudes (Chen 2011; Dahms & Killen, 2023), deeper depths (Currey 2015), elevations (Comte Grenouillet, 2013). Collectively, distributional transboundary governance (Palacios-Abrantes 2022) disproportionate impact protein lower (Lam Accurately projected collation synthesis wide range disciplines, including laboratory- field-based physiology thermal tolerance limits, genetics capacity, community (Waller using otolith-derived rate estimates Bluefin tuna, Trueman (2023) showed become thermally limiting species, suitability modeling demonstrated lack suitable means waters always viable option (Rutterford 2015). Vertical compression further exacerbated combined fishing pressure, deoxygenation, elasmobranchs restricted narrower depths, discussed extensive Waller Issue. highlighted Mukherjee Bhat empirically tested influence regimes foraging, shoaling three tropical found displayed constant versus periodic exposure elevated temperatures. Meanwhile, Ellis West Scotland cod exhibited poleward shift 1985 2021, trend shared Celtic Irish Sea stocks. Ultimately, individual- population-level interacting require innovative combine information presence/absence (Ellis Shelton 2022), tagging sensor technologies 2024), experiments (Killen Bhat, tags (Cordoleani embracing machine learning artificial intelligence (Sonnewald One successful involves building strengthening communication academia, policymakers capital nature-based solutions. Monitoring, protecting, supporting entire cycle, effective planning. About 30 years ago, industry authorities focused mainly food. There now need ensure long-term security context marine, coastal, riverine (Hák 2016). decade now, targets contributing healthy productive environment commercial recreational sectors (Rice Connolly, 2007). includes emergence decision-making process (Graham sharing ownership fishers incentive sustainably participatory (Hart, As decision makers try manage alongside growing occupying space, offshore wind infrastructure, evidence scientific advice activities whole (Piet Murray perspective emerging issues collaborative platforms offer address rapidly climatic, ecological, socioeconomic landscapes. Key themes addressed trade-off climatic renewable its impacts fisheries, value quantifying gene mitigating transition issue availability factor Exploring fill gaps gathering pace. Dawson used otolith daily rings demonstrate 2-month mismatch closure European sea bass peak window supplying northern Wales. Multiple grounds Freeman explore fine-scale use newly settled bass, high abundances sandflat stomach fullness indices sampled saltmarshes, whereas differences two nearby Collectively suggest vary short microhabitats estuary fulfill roles, providing predation improved opportunities. highlights full suite types seascape opportunities early efforts histories fishes depend nearshore ten Brink guilds (estuarine residents vs. estuarine-dependent grounds) exhibit somatic availability. seafood considered fastest-growing traded products, reflecting consumption habits around world (FAO, pointing pressures influencing populations. heatwaves, contaminants, parasites, hypoxia fitness), bringing concerns well-being. framework-setting safeguard resilient maritime economies (UK Government, MOAT, OSPAR, 2021), adaptation mitigate sustainability aquaculture sectors. concept brings humans, plants, environment, offering toolbox (Queenan 2017; Stentiford Nguyen describe symbiotic relationships anemones, insights mechanisms acclimation immunological naturally occurring toxins, basis unique needs. de Roos eloquently explains balancing consumer outcomes, chains, dietary guidelines optimize delivery regions source nutrition (Robinson yields nutrients maximized (de Roos, novel vital environmentally societally strive net zero carbon emissions 2050. We immensely proud hosted cohosting Cefas symbolic ambition meaningful collaborations academic government scientists. participants presenters conference spanned backgrounds, stakeholders. were stimulating talks, vibrant discussion sessions, exuberant interactions, ensuring best possible mixing people backgrounds stimulate conversations ideas improving field. Cross-disciplinary initiatives engaging public included art exhibition ("Connecting Shoals") exploring enhance engagement science, documentary ("Riverwoods") highlighting perilous state Scottish deforestation. During week, made films memories (Sturrock, 2024a) young marginalized communities, general while big technology 2024b). hope Journal Biology helpful snapshot multidisciplinary showcased conference, exciting still come. Conceptualisation, writing, review: E.J.O., R.P.V. A.M.S. grateful co-editors Dr Martin Wilkes David Murray, editor-in-chief Michel Kaiser, reviewers whose contributions helped thank Council, Essex, Cefas, Buckland Foundation, COST Action CA19107 SEA-UNICORN supported Cooperation Technology, Wiley, Thelma Biotel, Fishtrack Limited, Viewpoint Behavior Echoview financial logistical Symposium. Phil Lamb Kirsty Bradley graphical design, organizing committees attendees success. E.J.O. acknowledges funding NERC (NE/Y001184/1). Salary provided UKRI Future Leaders Fellowship [MR/V023578/1].

Язык: Английский

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Spiny dogfish, Squalus suckleyi, shows a good tolerance for hypoxia but need long recovery times

Conservation Physiology, Год журнала: 2024, Номер 12(1)

Опубликована: Янв. 1, 2024

Abstract Pacific spiny dogfish, Squalus suckleyi, move to shallow coastal waters during critical reproductive life stages and are thus at risk of encountering hypoxic events which occur more frequently in these areas. For effective conservation management, we need fully understand the consequences hypoxia on marine key species such as elasmobranchs. Because their benthic style, hypothesized that S. suckleyi tolerant able efficiently regulate oxygen consumption, anaerobic metabolism is supported by a broad range metabolites including ketones, fatty acids amino acids. Therefore, studied consumption rates, ventilation frequency amplitude, blood gasses, acid–base regulation, changes plasma tissue progressive hypoxia. Our results show levels (Pcrit) where oxyregulation lost were indeed low (18.1% air saturation or 28.5 Torr 13°C). However, many dogfish behaved oxyconformers rather than oxyregulators. Arterial PO2 mostly decreased linearly with decreasing environmental PO2. Blood gases status dependent open versus closed respirometry but both set-ups increased. Hypoxia below Pcrit resulted an up-regulation glycolysis, evidenced increased lactate all tissues except brain. Elasmobranchs typically rely ketone bodies oxidative substrates, concentrations acetoacetate β-hydroxybutyrate observed white muscle and/or recovering fish. Furthermore, reductions isoleucine, glutamate, glutamine other observed. After 6 hours normoxic recovery, persisted only returned normal most tissues. This emphasizes importance using suitable bioindicators adjusted preferred metabolic pathways target physiology. We conclude can tolerate severe transient events, recovery slow negative impacts be expected when persists.

Язык: Английский

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Fine-scale residency and temperature-driven habitat selection in a migratory shark species

Environmental Biology of Fishes, Год журнала: 2024, Номер unknown

Опубликована: Дек. 11, 2024

Abstract Many marine species exhibit complex and diverse movements that vary across spatial temporal scales. These must be accounted for when designing effective management conservation efforts. While environmental cues such as temperature salinity have been shown to influence the of mobile species, it is increasingly documented social factors can also space use population behaviour. Understanding how various movement enhances our ability predict highly dynamic ocean species. Spurdog ( Squalus acanthias ), known their tendency aggregate both coastal oceanic environments, are an ideal model studying drivers movement. To investigate habitat selection in spurdog, we conducted acoustic telemetry study from June 2016 July 2017, tagging 51 spurdog a partially enclosed fjordic sea loch on west coast Scotland. The thermal profile Loch Etive was recorded complement data. Our revealed pivotal driver with unique environment fjord enabling year-round residency at previously undocumented scale, suggesting habitats may especially important This demonstrates importance understanding influences develop effective, climate-resilient strategies other

Язык: Английский

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