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Rapid growth in bio-logging-the use of animal-borne electronic tags to document the movements, behaviour, physiology and environments of wildlife-offers opportunities to mitigate biodiversity threats and expand digital natural history archives. Here we present a vision to achieve such benefits by accounting for the heterogeneity inherent to bio-logging data and the concerns of those who collect and use them. First, we can enable data integration through standard vocabularies, transfer protocols and aggregation protocols, and drive their wide adoption. Second, we need to develop integrated data collections on standardized data platforms that support data preservation through public archiving and strategies that ensure long-term access. We outline pathways to reach these goals, highlighting the need for resources to govern community data standards and guide data mobilization efforts. We propose the launch of a community-led coordinating body and provide recommendations for how stakeholders-including government data centres, museums and those who fund, permit and publish bio-logging work-can support these efforts., Competing Interests: Competing interests: C.R. is the founding president of the International Bio-Logging Society (2017–2024), and F.C., S.C.D. and P.N. are the co-chairs of the society’s Data Standardisation Working Group. All other co-authors are members of the society and helped to conceive ideas through this working group. F.C. is the society’s current president and S.C.D. is a member of its executive committee. A.P.B.C. oversees management of the Seabird Tracking Database, C.Y.K. is the network coordinator of ATN, E.F. is a developer and manager of OBIS-SEAMAP, F.U. is former database designer of Euromammals, F.C. is coordinator of Euromammals, H.D. is former coordinator and current senior technical adviser of WRAM, J.D.P. is director of data operations of the OTN, L.B. is former data management director (2014–2020) of the OTN (with OTN 2010–2021), M.P.D. formerly coordinated management of the Seabird Tracking Database and S.C.D. is data curator of Movebank., (© 2025. The Authors and European Commission Joint Research Centre, under exclusive licence to Springer Nature Limited.)

Global biodiversity is facing unprecedented pressures, calling into question the effectiveness of existing governance systems aimed at halting extinctions. Renewed hope arose with the recent Conference of the Parties (COP) to the Convention on Biological Diversity (COP15 December 2022) and the Convention on International Trade in Endangered Species (COP19 November 2022). Yet, barriers remain that hamper biodiversity conservation. Identifying and overcoming these barriers is crucial for success. We considered previous lessons learned to show that current barriers to conservation are centered on a multidimensional array of mismatches among legal (law), ecological (science), and sociocultural (human) dimensions across the short, medium, and long term. Focusing on highly migratory marine megafauna (whales, sharks, and turtles), we used the Rubik's cube as a metaphor to conceptualize the multidimensional mismatches and devised a pathway for solutions that is highly dependent on strict alignment across all dimensions. We recommend the continuous cycling across all dimension interfaces to align the use (and update) of regulations and processes in law, improve data and experimentation methods in science, and develop education and engagement actions in the human dimension. This timely alignment across all dimensions is key to achieving biodiversity targets and avoiding further extinctions., (© 2024 The Author(s). Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology.)

Fisher's general principle for sex allocation holds that population sex ratios are typically balanced because parents producing the rare sex are benefited and the rare sex alternates over time. In species that have temperature-dependent sex determination (TSD), thermal reaction norms need to be adjusted at the population level to avoid extremely biased sex ratios and extinction. Extant species with TSD experienced drastic climatic changes in the geological past and must necessarily have mechanisms of adaptation. I propose here a conceptual framework to explain how TSD curves could be adjusted by means of natural selection, based on Fisher's equilibrium sex-ratio principle. Through a process that alternatively favors mothers that tend to produce the rare sex under new temperatures, sex ratios eventually return toward a theoretical equilibrium. Prerequisites for this model are variability among mothers in the tendency to produce a particular sex at a given temperature (i.e., variability in the thermal reaction norm), inheritance of this trend, and higher fitness of the rare sex. This straightforward mechanism could facilitate thermal adaptation in species with TSD over multiple generations., (© 2024 John Wiley & Sons Ltd.)

Many fish use a set of pharyngeal jaws in their throat to aid in prey capture and processing, particularly of large or complex prey. In this study-combining dissection, CT scanning, histology, and performance testing-we demonstrate a novel use of pharyngeal teeth in the ocean sunfish (Mola mola), a species for which pharyngeal jaw anatomy had not been described. We show that sunfish possesses only dorsal pharyngeal jaws where, in contrast to their beaklike oral teeth, teeth are recurved spikes, arranged in three loosely connected rows. Fang-like pharyngeal teeth were tightly socketed in the skeletal tissue, with shorter, incompletely-formed teeth erupting between, suggesting tooth replacement. Trichrome staining revealed teeth anchored into their sockets via a combination of collagen bundles originating from the jaw connective tissue and mineralized trabeculae extending from the teeth bases. In resting position, teeth are nearly covered by soft tissue; however, manipulation of a straplike muscle, running transversely on the dorsal jaw face, everted teeth like a cat's claws. Adult sunfish suction feed almost exclusively on gelatinous prey (e.g., jellyfish) and have been observed to jet water during feeding and other activities; flume experiments simulating jetting behavior demonstrated adult teeth caught simulated gelatinous prey with 70%-100% success, with the teeth immobile in their sockets, even at 50x the jetting force, demonstrating high safety factor. We propose that sunfish pharyngeal teeth function as an efficient retention cage for mechanically challenging prey, a curious evolutionary convergence with the throat spikes of divergent taxa that employ spitting and jetting., (© 2024 The Author(s). The Anatomical Record published by Wiley Periodicals LLC on behalf of American Association for Anatomy.)

The current climate warming is a challenge to biodiversity that could surpass the adaptation capacity of some species. Hence, understanding the means by which populations undergo an increase in their thermal tolerance is critical to assess how they could adapt to climate warming. Specifically, sea turtle populations could respond to increasing temperatures by (1) colonizing new nesting areas, (2) nesting during cooler times of the year, and/or (3) by increasing their thermal tolerance. Differences in thermal tolerance of clutches laid by different females would indicate that populations have the potential to adapt by natural selection. Here, we used exhaustive information on nest temperatures and hatching success of leatherback turtle (Dermochelys coriacea) clutches over 14 years to assess the occurrence of individual variability in thermal tolerance among females. We found an effect of temperature, year, and the interaction between female identity and nest temperature on hatching success, indicating that clutches laid by different females exhibited different levels of vulnerability to high temperatures. If thermal tolerance is a heritable trait, individuals with higher thermal tolerances could have greater chances of passing their genes to following generations, increasing their frequency in the population. However, the high rate of failure of clutches at temperatures above 32°C suggests that leatherback turtles are already experiencing extreme heat stress. A proper understanding of mechanisms of adaptation in populations to counteract changes in climate could greatly contribute to future conservation of endangered populations in a rapidly changing world., (© 2024 John Wiley & Sons Ltd.)

Levels of dissolved oxygen in open ocean and coastal waters are decreasing (ocean deoxygenation), with poorly understood effects on marine megafauna. All of the more than 1000 species of elasmobranchs (sharks, skates, and rays) are obligate water breathers, with a variety of life-history strategies and oxygen requirements. This review demonstrates that although many elasmobranchs typically avoid hypoxic water, they also appear capable of withstanding mild to moderate hypoxia with changes in activity, ventilatory responses, alterations to circulatory and hematological parameters, and morphological alterations to gill structures. However, such strategies may be insufficient to withstand severe, progressive, or prolonged hypoxia or anoxia where anaerobic metabolic pathways may be used for limited periods. As water temperatures increase with climate warming, ectothermic elasmobranchs will exhibit elevated metabolic rates and are likely to be less able to tolerate the effects of even mild hypoxia associated with deoxygenation. As a result, sustained hypoxic conditions in warmer coastal or surface-pelagic waters are likely to lead to shifts in elasmobranch distributions. Mass mortalities of elasmobranchs linked directly to deoxygenation have only rarely been observed but are likely underreported. One key concern is how reductions in habitat volume as a result of expanding hypoxia resulting from deoxygenation will influence interactions between elasmobranchs and industrial fisheries. Catch per unit of effort of threatened pelagic sharks by longline fisheries, for instance, has been shown to be higher above oxygen minimum zones compared to adjacent, normoxic regions, and attributed to vertical habitat compression of sharks overlapping with increased fishing effort. How a compound stressor such as marine heatwaves alters vulnerability to deoxygenation remains an open question. With over a third of elasmobranch species listed as endangered, a priority for conservation and management now lies in understanding and mitigating ocean deoxygenation effects in addition to population declines already occurring from overfishing., (© 2024 The Author(s). Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.)

While polyandry in sea turtles is indicated through multiple‐paternity analyses of offspring, confirmed observations of the same female mating with multiple males are extremely challenging to obtain. To contribute to this discussion, we analysed a long‐term photo‐identification database (>20 years) of adult male and female loggerhead sea turtles frequenting the breeding area of Zakynthos, Greece, Mediterranean. A total of 38 records of mating individuals within and across seasons were assimilated via field surveys and citizen science records between 2003 and 2020. For one female, we recorded it mating with two different males within a 5.5‐h interval on the same day in 2015. This observation constitutes the first direct evidence of polyandry in sea turtles, in addition to highlighting the potential for photo‐identification to contribute information on less well‐known aspects of sea turtle biology, such as validating outputs of genetic studies. [ABSTRACT FROM AUTHOR]

Climate warming and the feminization of populations due to temperature‐dependent sex determination may threaten sea turtles with extinction. To identify sites of heightened risk, we examined sex ratio data and patterns of climate change over multiple decades for 64 nesting sites spread across the globe. Over the last 62 years the mean change in air temperature was 0.85°C per century (SD = 0.65°C, range = −0.53 to +2.5°C, n = 64 nesting sites). Temperatures increased at 40 of the 64 study sites. Female‐skewed hatchling or juvenile sex ratios occurred at 57 of the 64 sites, with skews >90% female at 17 sites. We did not uncover a relationship between the extent of warming and sex ratio (r62 = −0.03, p =.802, n = 64 nesting sites). Hence, our results suggest that female‐hatchling sex ratio skews are not simply a consequence of recent warming but have likely persisted at some sites for many decades. So other factors aside from recent warming must drive these variations in sex ratios across nesting sites, such as variations in nesting behaviour (e.g. nest depth), substrate (e.g. sand albedo), shading available and rainfall patterns. While overall across sites recent warming is not linked to hatchling sex ratio, at some sites there is both is a high female skew and high warming, such as Raine Island (Australia; 99% female green turtles; 1.27°C warming per century), nesting beaches in Cyprus (97.1% female green turtles; 1.68°C warming per century) and in the Dutch Caribbean (St Eustatius; 91.5% female leatherback turtles; 1.15°C warming per century). These may be among the first sites where management intervention is needed to increase male production. Continued monitoring of sand temperatures and sex ratios are recommended to help identify when high incubation temperatures threaten population viability. [ABSTRACT FROM AUTHOR]

Projection models are being increasingly used to manage threatened taxa by estimating their responses to climate change. Sea turtles are particularly susceptible to climate change as they have temperature‐dependent sex determination and increased sand temperatures on nesting beaches could result in the 'feminisation' of hatchling sex ratios for some populations. This study modelled likely long‐term trends in sand temperatures and hatchling sex ratios at an equatorial nesting site for endangered green turtles (Chelonia mydas) and critically endangered hawksbill turtles (Eretmochelys imbricata). A total of 1078 days of sand temperature data were collected from 28 logger deployments at nest depth between 2018 and 2022 in Papua New Guinea (PNG). Long‐term trends in sand temperature were generated from a model using air temperature as an environmental proxy. The influence of rainfall and seasonal variation on sand temperature was also investigated. Between 1960 and 2019, we estimated that sand temperature increased by ~0.6°C and the average hatchling sex ratio was relatively balanced (46.2% female, SD = 10.7). No trends were observed in historical rainfall anomalies and projections indicated no further changes to rainfall until 2100. Therefore, the sex ratio models were unlikely to be influenced by changing rainfall patterns. A relatively balanced sex ratio such as this is starkly different to the extremely female‐skewed hatchling sex ratio (>99% female) reported for another Coral Sea nesting site, Raine Island (~850 km West). This PNG nesting site is likely rare in the global context, as it is less threatened by climate‐induced feminisation. Although there is no current need for 'cooling' interventions, the mean projected sex ratios for 2020–2100 were estimated 76%–87% female, so future interventions may be required to increase male production. Our use of long‐term sand temperature and rainfall trends has advanced our understanding of climate change impacts on sea turtles. [ABSTRACT FROM AUTHOR]

Climate change is an environmental emergency threatening species and ecosystems globally. Oceans have absorbed about 90% of anthropogenic heat and 20%-30% of the carbon emissions, resulting in ocean warming, acidification, deoxygenation, changes in ocean stratification and nutrient availability, and more severe extreme events. Given predictions of further changes, there is a critical need to understand how marine species will be affected. Here, we used an integrated risk assessment framework to evaluate the vulnerability of 132 chondrichthyans in the Eastern Tropical Pacific (ETP) to the impacts of climate change. Taking a precautionary view, we found that almost a quarter (23%) of the ETP chondrichthyan species evaluated were highly vulnerable to climate change, and much of the rest (76%) were moderately vulnerable. Most of the highly vulnerable species are batoids (77%), and a large proportion (90%) are coastal or pelagic species that use coastal habitats as nurseries. Six species of batoids were highly vulnerable in all three components of the assessment (exposure, sensitivity and adaptive capacity). This assessment indicates that coastal species, particularly those relying on inshore nursery areas are the most vulnerable to climate change. Ocean warming, in combination with acidification and potential deoxygenation, will likely have widespread effects on ETP chondrichthyan species, but coastal species may also contend with changes in freshwater inputs, salinity, and sea level rise. This climate-related vulnerability is compounded by other anthropogenic factors, such as overfishing and habitat degradation already occurring in the region. Mitigating the impacts of climate change on ETP chondrichthyans involves a range of approaches that include addressing habitat degradation, sustainability of exploitation, and species-specific actions may be required for species at higher risk. The assessment also highlighted the need to further understand climate change's impacts on key ETP habitats and processes and identified knowledge gaps on ETP chondrichthyan species., (© 2024 The Author(s). Global Change Biology published by John Wiley & Sons Ltd.)

The ocean sunfish is a large fish for which many aspects of its ecology and biology are still poorly known. Electronic tagging was used to provide the first information on the movements of an ocean sunfish from the northwestern Mediterranean. The sunfish moved towards the Gibraltar strait over the year and displayed substantial movements in the water column. The potential of the tagging technique employed for studying its behavior and long-term migratory dynamics, and assessing the post-release survival of ocean sunfish is highlighted., (© 2024 The Author(s). Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.)

The ocean sunfishes are currently represented by five species within three genera: Mola mola (Linnaeus, 1758), Mola alexandrini (Ranzani, 1839), Mola tecta (Nyegaard, Sawai, Gemmell, Gillum, Loneragan, Yamanoue & Stewart, 2017) (Sawai et al., 2018), Masturus lanceolatus (Lienard, 1840), and Ranzania laevis (Pennant, 1776). Growing conservation concerns have led to an ongoing re-examination of their classification status on the International Union for the Conservation of Nature Red Lists, a process requiring the latest data to best support their conservation management on a global scale. Here we report the first sighting of Masturus lanceolatus in the northeast Irish Sea, representing a new northerly range limit for this species in the northeast Atlantic. The species is more commonly reported in tropical seas, and in the Western Atlantic they occur from North Carolina in the United States to southeast Brazil. This sighting increases the most northerly range limit by 2610 km, providing additional insight into the ecology and potentially changing distribution of this generally considered tropical megafaunal species., (© 2024 Fisheries Society of the British Isles.)

The abundance of large marine dinoflagellates has declined in the North Sea since 1958. Although hypotheses have been proposed to explain this diminution (increasing temperature and wind), the mechanisms behind this pattern have thus far remained elusive. In this article, we study the long-term changes in dinoflagellate biomass and biodiversity in relation to hydro-climatic conditions and circulation within the North Atlantic. Our results show that the decline in biomass has paralleled an increase in biodiversity caused by a temperature-induced northward movement of subtropical taxa along the European shelf-edge, and facilitated by changes in oceanic circulation (subpolar gyre contraction). However, major changes in North Atlantic hydrodynamics in the 2010s (subpolar gyre expansion and low-salinity anomaly) stopped this movement, which triggered a biodiversity collapse in the North Sea. Further, North Sea dinoflagellate biomass remained low because of warming. Our results, therefore, reveal that regional climate warming and changes in oceanic circulation strongly influenced shifts in dinoflagellate biomass and biodiversity., (© 2024 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

Ernest, R.G.; Martin, R.E.; Desjardin, N.A.; Scripter, M.J.; Scarola, J.C.; Kim, H., and Trindell, R., 2025. Changes in loggerhead sea turtle nesting behavior on a nourished beach in southeast Florida. Journal of Coastal Research, 41(1), 27–48. Charlotte (North Carolina), ISSN 0749-0208. Under Florida's Strategic Beach Management Plan, large volumes of sand dredged offshore are routinely placed on beaches to mitigate shoreline erosion, a process known as beach nourishment. Sandy beaches, vital to the state's tourism economy, are also biologically critical to NW Atlantic loggerhead sea turtles (Caretta caretta). Long-term data have shown that nourishment projects can negatively affect sea turtle nesting behavior, and to date, no design changes have effectively ameliorated these impacts. The frequency of beach nourishment projects in Florida will likely increase with a changing climate, and thus, it is imperative that they be designed and built to enhance sea turtle nesting habitat. In this study, real-time kinematic GPS and binned logistic regression analyses were used to identify changes in loggerhead sea turtle nesting success, beach utilization, and nest placement associated with a beach nourishment project on Hutchinson Island, Florida. Beach profile characteristics (width, slope, and elevation) were analyzed before and after nourishment to determine the likelihood of a turtle either nesting or abandoning its nesting attempt. Results showed that: (1) fewer loggerhead nests were placed on the nourished beach, even though the number of nesting attempts was similar before and after nourishment; (2) the percentage of nests washed out on the wide, flat nourished beach was 3.5 times greater than on the narrower, naturally sloped beach that preceded nourishment; and (3) a change in the cross-sectional beach profile was most strongly associated with decreased odds of nesting following nourishment. It is recommended that future nourishment projects in central and southeast Florida be designed and constructed, in consideration of local conditions, with as much slope as possible from the waterline to the dune. [ABSTRACT FROM AUTHOR]

The resource-use hypothesis proposed by Elisabeth S. Vrba suggests that lineages display varying tendencies toward generalism or specialization in biome occupancy, with a tendency towards the accumulation of specialists due to their higher rate of speciation through vicariance. It also posits differences in biome occupancy patterns driven by the environmental characteristics of biomes, with a higher presence of biome specialist species in biomes that are placed in the extremes of the global climatic gradients. Here, we tested this hypothesis in turtles, a very ancient and morphologically stable lineage, representing a remarkable diversity with 357 species, many of which are threatened with extinction. We analyzed the resource-use hypothesis in a phylogenetic context within the Testudines lineage. For this purpose, a presence/absence matrix was compiled for all species across all 10 terrestrial biomes. Their distribution across biomes was contrasted with 10,000 Monte Carlo simulations. The relationship between diversification rates and both the biomic specialization index and the biomes occupied by specialists species was evaluated. The results demonstrate strong consistency with Vrba's hypothesis, revealing a higher number of biome specialist species than expected by chance, with a significant accumulation of species in tropical ecosystems. These trends also were observed for ecological groups (terrestrial and freshwater species). In addition, higher diversification rates were observed for biome specialist species, although the particular biome occupied did not significantly influence their diversification rates. [ABSTRACT FROM AUTHOR]

Marine microorganisms play a critical role in regulating atmospheric CO2 concentration via the biological carbon pump. Deposition of continental mineral dust on the sea surface increases carbon sequestration but the interaction between minerals and marine microorganisms is not well understood. We discovered that the interaction of clay minerals with dissolved organic matter and a γ-proteobacterium in seawater increases Transparent Exopolymer Particle (TEP) concentration, leading to organoclay floc formation. To explore this observation further, we conducted a microcosm experiment using surface seawater collected from the Spring 2023 phytoplankton bloom in the Gulf of Maine. Unfiltered (natural community) and filtered (200 μm and 3 μm) seawater was sprayed with clay (20 mg L− 1 and 60 mg L− 1) and incubated. All clay treatments led to a tenfold increase in TEP concentration. 16S rRNA gene amplicon sequence analyses of seawater and settled organoclay flocs showed the dominance of α-proteobacteria, γ-proteobacteria, and Bacteroidota. The initial seawater phytoplankton community was dominated by dinoflagellates followed by a haptophyte (Phaeocystis sp.) and diatoms. Following clay addition, dinoflagellate cell abundance declined sharply while diatom cell abundance increased. By analyzing organoclay flocs for 18S rRNA we confirmed that dinoflagellates were removed in the flocs. The clay amendment removed as much as 50% of phytoplankton organic carbon. We then explored the fate of organoclay flocs at the next trophic level by feeding clay and phytoplankton (Rhodomonas salina) to Calanus finmarchicus. The copepod ingested R. salina and organoclay flocs and egested denser fecal pellets with 1.8- to 3.6- fold higher sinking velocity compared to controls. Fecal pellet density enhancement could facilitate carbon sequestration through zooplankton diel vertical migration. These findings provide insights into how atmospheric dust-derived clay minerals interact with marine microorganisms to enhance the biological carbon pump, facilitating the burial of organic carbon at depths where it is less likely to exchange with the atmosphere. [ABSTRACT FROM AUTHOR]

Introduction: Sea turtles are ideal flagship and umbrella species for marine biodiversity conservation. The quality of nesting grounds is crucial for the successful reproduction of sea turtles, as it determines whether they can successfully nest and hatch. The Xisha Islands represent the largest remaining nesting grounds for green turtles in China. However, they face numerous threats and lack management guidelines for nesting ground restoration. Methods: In this study, we continuously monitored the beach changes and coastal erosion on North Island, which is located in the northern region of the Xisha Islands, from 2019 to 2022. Results: From 2020 to 2022, the beach area on North Island decreased annually by 11,800 m2, accounting for 24.39% of the beach area in 2020. The proportion of suitable nesting sand types (including coarse and medium sands) also decreased annually, with a reduction of 40–70% on the southern beach of North Island. The peak nesting period of green turtles on North Island coincides with the frequent occurrence of typhoons in the South China Sea, causing tidal surges that inundate green turtle nests, resulting in an average nest loss rate of 35.25%. Discussion: Based on the above threats, it is recommended to promptly initiate habitat restoration in severely eroded areas of green turtle nesting grounds to prevent further declines in nesting area and quality. Additionally, measures such as nest relocation should be implemented to enhance green turtle reproductive success. [ABSTRACT FROM AUTHOR]

Current climate change, particularly ocean warming, will induce shifts in marine species distribution and composition, affecting the marine food web and, thus, trophic interactions. Analyses of the stable isotopes 13C and 15N are commonly used to detect trophic markers for food web analyses. With the current standard methods used in food web ecology, it is still challenging to identify potential changes in the uptake and utilization of trophic markers. In this work, we present a 13C-enrichment analysis by NMR spectroscopy to track the uptake and utilization of dietary carbon in a simple laboratory experiment of a primary producer and its consumer (algae and bivalve). In particular, we tested the hypothesis of a temperature-dependent use of dietary carbon by tracing the incorporation of 13C-atoms. Unicellular phytoplankton, Phaeodactilum tricornutum , was reared in a medium containing 13C-labeled bicarbonate. The accompanying 13C-NMR spectra of labeled P. tricornutum showed a specific profile of 13C-labeled compounds, including typical trophic markers such as the polyunsaturated omega-3 fatty acid eicosapentaenoic acid (EPA). Afterwards, 13C-labeled P. tricornutum was fed to King scallops, Pecten maximus , kept at two different temperatures (15°C and 20°C). Tissue-specific NMR spectra of P. maximus revealed elevated 13C-NMR signals, particularly of the fatty acid EPA in the digestive gland, which was not evident in muscle tissue. The comparison between the two temperatures indicated a change in trophic markers. At the higher temperature, less unsaturated fatty acids were detected in the digested gland, but increased 13C-labels in sugars were detected in the adductor muscle. This might indicate a change in the uptake and utilization of the trophic marker EPA in P. maximus due to a shift in energy conversion from favored beta-oxidation at colder temperatures to conversion from carbohydrates in the warmth. Our approach indicates that besides the accumulation of trophic markers, their incorporation and conversion are additional important factors for the reliable interpretation of trophic linkages under climate change. [ABSTRACT FROM AUTHOR]

Marine harmful algal blooms (HAB) have been implicated in marine mammal die-offs; but the relationship between sub-lethal algal toxicity and marine mammal vulnerability to human activities has not been assessed. HAB toxins can result in compromised neurological or muscular systems and we posit these conditions can expose marine mammals to increased likelihood of entanglement in commercial fishing gear or ship strike. To investigate whether HABs and large whale injuries and deaths were associated, we assessed the spatiotemporal co-occurrence of HAB events and large whale mortalities/injuries in U.S. east (from 2000-2021) and west (2007-2021) coastal waters. The number of mortalities/injuries was frequently higher in years with large-scale or severe HABs. We found statistically significant relationships between the occurrence of HABs and whale mortalities/injuries in west coast waters – at least three additional whale deaths/injuries were detected near an active HAB than in areas where a HAB was not reported. This relationship was similarly positive but weaker for east coast waters, a difference that may be attributable to differing oceanographic features, or approaches used in whale data collection, between coasts. Saxitoxin-producing Alexandrium was the most common causative agent on both the east (64.1%) and west (57.8%) coasts; and domoic acid-producing Pseudo-nitzschia was more common along the west (33.3%) than the east coast (8.7%). Algal toxins can be entrained in marine ecosystems, including in whale prey, and can chronically persist in marine mammals. Given many whale deaths/injuries result from fishing gear entanglement and vessel strikes, algal-induced morbidities may diminish whale capacities to detect or avoid fishing gear and approaching vessels. While there was much interannual variability, general increasing trends were observed in both whale death/injury and HAB datasets which may be attributable to increased monitoring or rising ocean temperatures. HAB prediction modeling has become increasingly sophisticated and could be used as a tool to reduce whale mortality by limiting human activities (e.g., curtailing fishing operations) when HABs, whale occurrence, and maritime activities are expected to overlap. Additional systematic data collection is needed to track and model mechanisms underlying relationships between HABs and incidental whale mortality. [ABSTRACT FROM AUTHOR]

Understanding how sea turtle species move through the environment and respond to environmental features is fundamental for sustainable ecosystem management and effective conservation. This study investigates the habitat suitability of the loggerhead sea turtle (Caretta caretta) in the Adriatic and Northern Ionian Seas (Central-Eastern Mediterranean) by developing and validating a multidisciplinary framework that leverages machine learning to investigate movement patterns collected by satellite tags Argos satellite tags. Satellite tracking data, enriched with sixteen environmental variables from the Copernicus Marine Service and EMODnet-bathymetry, were analyzed using Random Forest models, obtaining an accuracy of 80.9% when classifying presence versus pseudo-absence of loggerhead sea turtles. As main findings, sea bottom depth, surface chlorophyll (chl-a), and mixed layer depth (MLD) were identified as the most influential features in the habitat suitability of these specimens. Moreover, statistically significant differences, evaluated using t-test statistics, were found between coastal and pelagic locations, for the different seasons, in mixed layer depth, chl-a, 3D-clorophyll, salinity and phosphate. Although based on a limited sample of tagged animals, this study demonstrates that the distribution patterns of loggerhead sea turtles in Mediterranean coastal and pelagic areas are primarily influenced by sea water features linked to productivity and, consequently, to potential prey abundance. Additionally, this multidisciplinary framework presents a replicable approach that can be adapted for various species and regions. [ABSTRACT FROM AUTHOR]

Although parasitism is vital for ecosystem dynamics and food webs, the population effects of parasitism in the marine pelagic have received little attention. Pelagic copepods link primary producers and higher consumers in marine food webs and host numerous parasites that may affect reproduction, behavior, and survival. We present a simple model consisting of uninfected hosts, infected hosts, and the free‐living parasite stage and use it to investigate population dynamics and outbreak conditions of this host–parasite system. The host population growth is limited by a carrying capacity determined by resource availability and stoichiometric constraints. We parameterized the model for 10 copepod species with different traits but with the same Blastodinium‐like parasite. We derived a threshold ratio R0$$ {R}_0 $$ for establishing infection, which showed that the parasite could invade and persist in all hosts. The ability of parasites to invade host populations largely depended on traits of free‐living spores and host density. From numerical analysis, we found that the parasite typically induced oscillations in the host population. Host traits were important for infection dynamics: High host growth rates mitigated some of the consequences of infection, and larger copepods were more susceptible to infection than smaller ones. The model implies that parasitism can impact the functional role of the copepod population in the ecosystem, and the system as a whole. [ABSTRACT FROM AUTHOR]

This review provides a comprehensive summary of the current knowledge on marine zooplankton diversity and distribution, highlighting key advancements and future directions in the field. While the approach used in this review is necessarily broad, focusing on overarching trends and drivers of zooplankton diversity, it emphasizes recent methodological innovations. The review begins with an introduction to zooplankton, tracing the historical development of their research. It then explores the critical roles zooplankton play in ocean ecosystems, climate change, and the global economy. Next, the review examines the environmental and anthropogenic factors influencing marine zooplankton. Finally, it presents a comparison between marine and freshwater zooplankton and concludes with a discussion of the challenges facing current zooplankton diversity research and the presentation of possible directions and implementation strategies for advancing the understanding of zooplankton biodiversity and ecology. [ABSTRACT FROM AUTHOR]

The use of animal‐borne devices (= biologgers) has revolutionized the study of marine megafauna, yet there remains a paucity of data concerning the behavioral and physiological impacts of biologger attachment and retention. Here, we used animal‐borne cameras to characterize the behavior and dive duration of juvenile green turtles (Chelonia mydas) in The Bahamas for up to 210 min after biologger deployment (n = 58). For a "control," we used unoccupied aerial vehicles (UAVs) to collect comparable data from nonhandled green turtles (n = 25) in the same habitats. Animal‐borne footage revealed that immediately after release turtles spent 70%–80% of their time swimming with a mean dive duration of 45.3 ± 34.3 s (SD). Over time, the percentage of time spent swimming decreased alongside an increase in dive duration until reaching a plateau around 90 min. However, the "control" UAV data for time spent swimming and dive durations were more comparable to the behaviors observed immediately after biologger deployment than during the plateau. We observed no significant differences in dive durations based on body size, and differences in behaviors based on body size were also minimal. We conclude that the effects of handling stress and biologger attachment on the behavior and dive duration of juvenile green turtles are evident up to 90 min postdeployment. After that, it is possible that either: (1) the effects of biologger deployment and retention are negligible, but UAVs may produce biased data that overestimates the proportion of time turtles typically spend swimming or (2) longer durations (> 210 min) are necessary for turtle behaviors to return to nonhandled levels and UAVs accurately represent the proportion of time turtles typically spend swimming. Answering this question, alongside further research into the physiological and behavioral implications of handling stress and biologger attachment, is essential to improve ethical biologging guidelines for sea turtles. [ABSTRACT FROM AUTHOR]

Migratory species typically undertake demanding long‐distance journeys, across different habitat types during which they are exposed to multiple natural and anthropogenic stressors. Mortality during migration is typically high and may be human induced. Understanding individual responses to these selection pressures is rarely attempted because of the challenges of relating individual phenotypic and genetic data to migration success. Here, we show distinct single nucleotide polymorphism (SNP) sets significantly differentiated between Atlantic salmon smolts making successful migrations to sea and those that failed to migrate, in two different rivers. In contrast, morphological variation was not diagnostic of migration success. Populations from each river were genetically distinct, and while different genes were possibly implicated in migration success in each river, they related to common biological processes (e.g., osmoregulation and immune and stress response). Given that migration failure should quickly purge polymorphism at selected SNPs from a population, the question of how genetic diversity in these populations is maintained is an important one. Standing genetic variation could be maintained by different life history strategies and/or environmentally driven balancing selection. Our work highlights the importance of preserving genetic diversity to ensure evolutionary resilience at the population level and has practical implications for management. [ABSTRACT FROM AUTHOR]

Dynamic ocean management (DOM) is a critical approach for protecting highly migratory species amid environmental variability and change. We conducted an adapted systematic review to assess how animal movement and environmental data are used in DOM applications, identifying key data traits, barriers, and research priorities. Animal tag data inform initial assessments of species distributions, development of habitat models, near real‐time model inputs, and iterative model evaluation for dynamic management. In documented examples, effective translation of scientific insights into dynamic management products has resulted from early communication between researchers and stakeholders, integration of environmental and fisheries‐dependent data into advanced habitat modeling approaches, and reformatting of outputs for interdisciplinary needs. However, challenges persist around data gaps, science‐policy translation, and technical capacity limitations. Our findings highlight the importance of intentional, collaborative data collection, translation, and sharing to enable dynamic, climate‐resilient management of migratory species. We demonstrate DOM's adaptability and provide guidance for researchers and practitioners to contribute and use impactful data that informs responsive management decision‐making. [ABSTRACT FROM AUTHOR]

Animal tracking has opened the door to address many fundamental questions in ecology and conservation. Whilst historically animals have been tracked as a means to understand their large‐scale movements, such as migration, there is now a greater focus on using tracking to study movements over smaller scales, individual variation in movement or how movements shape social network structure. With this shift in focus also comes different tracking needs, including the need to track larger numbers of individuals.Tracking studies all face some technological limitations. For example, GPS and other active tracking solutions can collect fine‐scale movement data, but have a high cost per tag, limiting the number of individuals that can be followed. They also have high low‐energy costs of data acquisition and download, limiting time periods over which data can be collected. Low‐energy passive (e.g. PIT) or active (e.g. reverse GPS) tags can overcome these limitations, but instead require animals to remain within a bounded study area or to come into close proximity to detectors.Here we describe one solution that can overcome many current limitations by employing the massive global network of personal mobile phones as gateways for tracking animals using Bluetooth low‐energy (BLE) beacons. In areas with medium to high density of people, these simple‐to‐make beacons can provide regular updates of position over long time periods (battery life 1–3 years). We describe how to use off‐the‐shelf components to produce BLE beacons that weigh c. 5–6 g and cost <$7USD. Using field‐testing, we then show that beacons are capable of producing high‐frequency tracking data that can be used to build home ranges or to detect spatiotemporal co‐occurrences among individuals.BLE beacons are a low cost, low‐energy solution for studying organisms (e.g. birds, mammals and reptiles) living and moving in urban landscapes. Their low weight and small size makes them particularly well‐suited for tracking smaller species. When combined with fixed gateways, their use can also be extended to non‐urban habitats. Their high accessibility is likely to make them an attractive solution for many research projects. [ABSTRACT FROM AUTHOR]

Understanding the foraging behavior of marine animals in Antarctica is crucial for assessing their ecological significance and responses to environmental changes, such as seasonal changes in seawater or light hours. However, studying their responses to these seasonal changes remains challenging due to the difficult logistics of conducting observations, particularly during the harsh austral winter months. In this study, we investigated the influence of changes in seawater properties and light conditions on the seasonal foraging behavior of Weddell seals (Leptonychotes weddellii) in the Ross Sea, Antarctica. We affixed 64 Weddell seals with conductivity–temperature–depth tags for 3 consecutive years from 2021 to 2023 to record their locations and dive profiles, including depth, head acceleration, temperature, and salinity. We found that seals foraged more frequently in Modified Shelf Water and Ice Shelf Water than in Antarctic Surface Water. This preference could be connected to greater food availability. Seals also dove to greater depths and displayed increased activity in capturing prey during daylight hours. This behavior may correspond to the diel vertical migration of pelagic prey in response to varying light conditions. Consequently, marine fauna were confronted with distinct seasonal changes in the Antarctic environment and adjusted their foraging behaviors to respond to them. This highlights the importance of extrinsic factors in estimating their seasonal foraging behavior. [ABSTRACT FROM AUTHOR]

Distribution patterns of benthic dinoflagellates that are widely observed in tropical and temperate waters and have toxic potential are changing in response to ocean climate change. Although there have been no outbreaks associated with the genus Coolia affecting humans, it is crucial to understand their changing distribution and clearly identify the species in the study area to prepare for potential toxic events. In this study, five strains of Coolia species were isolated from macroalgae samples collected from Jeju Island and the eastern coastal waters of Korea. Through morphological and molecular analysis of these isolates, one strain was identified as Coolia palmyrensis , marking the first report of this species in Korea, and four strains as C. malayensis. One of the C. malayensis strains was isolated in Pohang on the eastern coast of Korea, where it had not been previously reported. From 2021 to 2023, monitoring of Jeju Island using a quantitative polymerase chain reaction (PCR) assay revealed that C. palmyrensis cells occurred mostly in autumn, with a maximum density of 242 cells g-1, and overwintering populations were observed in 2023. However, C. malayensis cells were not observed in this area. Additionally, C. malayensis was observed in Pohang and Ulsan, located further north than Jeju Island with maximum cell densities of 537 and 201 cells g-1, respectively. These data and our decade of monitoring experience confirmed the introduction and establishment of C. palmyrensis and habitat shift of C. malayensis in Korean coastal waters. This study provides advances for understanding of the relationships between climate-driven alterations and biogeographic distribution of these species. [ABSTRACT FROM AUTHOR]

Fractal scale-free structures are widely observed across a range of natural and synthetic systems, such as biological networks, internet architectures, and social networks, providing broad applications in the management of complex systems and the facilitation of dynamic processes. The global mean first-passage time (GMFPT) for random walks on the underlying networks has attracted significant attention as it serves as an important quantitative indicator that can be used in many different fields, such as reaction kinetics, network transport, random search, pathway elaboration, etc. In this study, we first introduce two degree-dependent random walk strategies where the transition probability is depended on the degree of neighbors. Then, we evaluate analytically the GMFPT of two degree-dependent random walk strategies on fractal scale-free tree structures by exploring the connection between first-passage times in degree-dependent random walk strategies and biased random walks on the weighted network. The exact results of the GMFPT for the two degree-dependent random walk strategies are presented and are compared with the GMFPT of the classical unbiased random walk strategy. Our work not only presents a way to evaluate the GMFPT for degree-dependent biased random walk strategies on general networks but also offers valuable insights to enrich the controlling of chemical reactions, network transport, random search, and pathway elaboration. [ABSTRACT FROM AUTHOR]

Lakshmanan, R.; Saravanan, R.; Kalidas, C.; Rajendran, P.; Babu, A.M.; Asha, P.S., and Joshi, K.K., 2024. Occurrence of the non-native mauve stinger, Pelagia cf. noctiluca, in coastal waters off Cape Comorin, southern Bay of Bengal. Journal of Coastal Research, 40(6), 1103–1110. Charlotte (North Carolina), ISSN 0749-0208. During a jellyfish survey in the southern Bay of Bengal, India, four scyphozoan jellyfish from the family Pelagiidae (Order: Semaeostomeae) were observed. The observed specimens were found at a depth of 1 to 2 m off the coast of Arockiapuram (8°05′ N, 77°11′ E), Cape Comorin (now Kanyakumari). The underwater photographic and video documentation with live colouration enabled the identification of the collected specimens as mauve stingers, Pelagia noctiluca (Forskal, 1775). The observed specimens have pink- or mauve-coloured hemispherical umbrellas with eight marginal tentacles that are transversely wrinkled and eight pear-shaped rhopalia. In general, P. noctiluca has a common distribution along the Atlantic Ocean, the Mediterranean Sea, and the Pacific Ocean; however, recordings of this species in Indian waters are considered rare and out of its documented distribution area. It has been reported earlier from Indian waters, and the nearest known distribution is from the Gulf of Mannar, Bay of Bengal. This species shows an invasive distribution in the warmer tropical environments due to its wide range of temperature tolerance. The species can be considered "invasive" as the periodic occurrence of large abundances in coastal waters occurs when this typically offshore species is advected shoreward in years when population densities appear to be exceptionally high. Consequently, it is problematic at the very periphery of its "natural range," thus differing from truly invasive species that have been introduced into a new area. The findings in this study suggest that specific hydrodynamic conditions may transport the permanent offshore population of P. noctiluca inshore, resulting in non-native outbreaks on shores. The study sheds light on the presence of the non-native oceanic mauve stinger in the Cape Comorin coastal waters in the Bay of Bengal, which alters the fisheries and tourism industries because it has a negative interaction with human recreational and coastal fishing activities. [ABSTRACT FROM AUTHOR]

A focus of sea turtle management has been reducing bycatch in commercial fisheries, but sustainable harvest for consumption is also an important objective in many nations. Identifying how much different fisheries contribute to turtle mortality could help focus limited management resources. We estimated national scale turtle catches for two fisheries in the Solomon Islands: a small‐scale reef fishery where turtles are caught for food and sale, and an offshore longline fishery where turtles are bycatch. The footprint of the longline fishery spanned the entire exclusive economic zone of the Solomon Islands and was 67 times bigger than the footprint of the small‐scale fishery. The median catch summed across both fisheries was ∼12,000 turtles in 2018, with 85%–97% of that catch in the small‐scale fishery. We suggest that turtle management in the Solomon Islands, a nation with globally significant turtle breeding populations, should focus on sustainable management of small‐scale coastal fisheries. [ABSTRACT FROM AUTHOR]

Sex‐ratio theory predicts that parents can optimise their fitness by producing offspring of the rare sex, yet there is a dearth of empirical evidence for adaptive sex allocation in response to the adult sex ratio (ASR). This is concerning, as anthropogenic disruption of the sex ratios of reproductive individuals threatens to cause demographic collapse in animal populations. Species with environmental sex determination (ESD) are especially at risk but may possess the capacity to adaptively influence offspring sex via control over the developmental environment. For example, reptiles with temperature‐dependent sex determination (TSD) could conceivably choose nest sites with thermal characteristics that produce offspring of the rare sex. To test this hypothesis, we seeded three secure outdoor ponds with different sex ratios (~M:F 3:1, 1:1, and 1:3) of adult painted turtles (Chrysemys picta), a reptile species with TSD. We then quantified nesting traits that could influence nest temperature and thus offspring sex ratio, including nesting date, nest depth, and nest canopy cover. We found no directional relationship between the ASR treatments and any measured nest traits and thus rejected our hypothesis. Interestingly, increased maternal body size was associated with reduced nest canopy cover, and this trend was more pronounced in the biased ASR treatments. If adaptive sex allocation occurs in this system, it instead may manifest via maternal epigenetic predisposition of offspring sex or in response to a phenomenon other than the ASR. [ABSTRACT FROM AUTHOR]

Turtles are a small clade of vertebrates despite having existed since the Late Triassic. Turtles have a conservative body plan relative to other amniotes, characterized by the presence of a shell and quadrupedality. This morphology is even retained in strong ecological specialists, such as sea turtles, which are secondarily adapted to marine locomotion by strong allometric scaling in their hands. It is possible that the body plan of turtles is strongly influenced by the presence of the shell, acting as a constraint to achieving greater diversity of body forms. Here, we explore the evolutionary allometric relationships of fore‐ and hindlimb stylopodia (i.e., humerus and femur) with one another as well as their relationship with shell size (carapace length) to assess evidence of constraint. All turtles, including Triassic shelled stem turtles, have near‐isometric relationships that do not vary strongly between clades, and evolve at slow evolutionary rates. This indeed indicates that body proportions of turtles are constrained to a narrow range of possibilities. Minor allometric deviations are seen in highly aquatic sea turtles and softshell turtles, which modified their shells by bone losses. Our allometric regressions allow accurate body size estimations for fossils. Several independent sea turtle lineages converged on maximum sizes of 2.2 m of shell length, which may be a biological maximum for the group. [ABSTRACT FROM AUTHOR]

Habitat‐based approaches to animal conservation are bolstered by an understanding of resource selection, that is, use of resources (i.e., habitat features) relative to their availability in the environment. Quantifying resource selection is especially valuable when data characterizing animal space use are limited, as is often the case with mobile and/or cryptic species. Documenting associations with habitat features can better inform management in space in time, while also revealing key insight into movement ecology and behavior. Here, we evaluate resource selection by a megaomnivore whose highly mobile nature within marine habitats has resulted in an incomplete understanding of drivers of space use. We used satellite telemetry to track 29 green turtles (Chelonia mydas) from an eastern Pacific foraging aggregation in San Diego Bay, California, USA during 2013–2023. Tracking produced 5023 Fastloc‐GPS points which we used to model selection for local environmental resources relative to their availability. We employed logistic models to evaluate associations with seagrass, bathymetry, and water temperatures, implementing a framework that additionally allowed us to explore the roles of season, diel period, and turtle body size. Our methods demonstrate an approach for down‐weighting observations according to assumed telemetry error and autocorrelation. Results from fine‐scale resource selection models provide evidence that green turtles in San Diego Bay select for eelgrass meadows (Zostera marina), particularly during the warmest months of the year, but the strength of this selection changes from day to night. We additionally found day–night shifts in depth and temperature selection that changed with turtle body size and season. We discuss these findings in the context of diel patterns in resting and foraging behavior in addition to seasonal changes in thermally sensitive metabolic rates. Our study documents resource associations and provides quantitative information for the management of sea turtle foraging populations and their habitats. We offer key insight into habitat use by green turtles in the eastern Pacific at a pivotal time when multiple indicators point to population growth and expansion within the region. [ABSTRACT FROM AUTHOR]

Marine turtles are a group of imperiled marine megafauna particularly vulnerable to anthropogenic stressors. Most long‐term studies of marine turtles are based on nesting surveys which focus on numbers of eggs, hatchlings, and nesting females. However, we know less about long‐term abundance trends of immature and adult turtles in the marine environment. To address this data gap, we examined records from 35,000 underwater visual census (UVC) dives (1993–2019) and short‐term in‐water turtle survey data (2009–2014) at Cocos Island, Costa Rica. During UVCs, trained divemasters from UnderSea Hunter recorded observations of two species of marine turtles—green Chelonia mydas and hawksbill Eretmochelys imbricata. Our short‐term in‐water surveys revealed that most turtles at Cocos are greens, but both immature and mature greens occur at Cocos. We analyzed long‐term UVC data using a hierarchical modeling approach and we modeled a 26% decrease in the relative abundance of turtles observed on dives each year. Our model also revealed potential interactions between tiger sharks and turtles, finding that for each additional tiger shark present during a dive, the predicted relative abundance of turtles decreased by 43%. Lastly, our model suggested the influence of environmental variation on marine turtle relative abundance; a 1°C increase in sea surface temperature (SST) decreased the predicted relative abundance of turtles by 7%. Our results suggest that marine turtles are sensitive to long‐term environmental and oceanographic changes, and potentially avoid certain areas to reduce exposure to tiger sharks. Given our study area is already protected, there needs to be more focus on protecting adult turtles during their movements across the Eastern Tropical Pacific. Our work also highlights the importance of long‐term underwater surveys to monitor adult turtles. [ABSTRACT FROM AUTHOR]

The loggerhead sea turtle (Caretta caretta) is sensitive to climate change and is responding by colonising the Western Mediterranean. To understand the rapid nesting increase in recent years in Spain, we sampled 45 hatchlings from 8 nests between 2016 and 2019. We sequenced a mtDNA D-loop region, genotyped 2291 SNPs using 2bRAD and collected data on clutch size, hatching success, and incubation duration. We confirmed that the colonisation has a Mediterranean and Atlantic mixed origin and we detected that these nests were laid by different females, except for two nests within the same season. Our results suggest that the recent increase in nesting is due to an increase in the number of colonising individuals rather than females born in the same area returning to breed. We hypothesize that this increase in the number of colonisers results from successful conservation efforts, feminisation of the populations of origin and earlier sexual maturation. However, the percentage of offspring females produced in Spain suggests that future returning individuals will aid to the settlement of the new population. These results allow defining the current status of this colonisation although future efforts are needed to detect remigrants to confirm the establishment of a resident population., (© 2024. The Author(s).)

Sea turtles are vulnerable to climate change since their reproductive output is influenced by incubating temperatures, with warmer temperatures causing lower hatching success and increased feminization of embryos. Their ability to cope with projected increases in ambient temperatures will depend on their capacity to adapt to shifts in climatic regimes. Here, we assessed the extent to which phenological shifts could mitigate impacts from increases in ambient temperatures (from 1.5 to 3°C in air temperatures and from 1.4 to 2.3°C in sea surface temperatures by 2100 at our sites) on four species of sea turtles, under a "middle of the road" scenario (SSP2-4.5). Sand temperatures at sea turtle nesting sites are projected to increase from 0.58 to 4.17°C by 2100 and expected shifts in nesting of 26-43 days earlier will not be sufficient to maintain current incubation temperatures at 7 (29%) of our sites, hatching success rates at 10 (42%) of our sites, with current trends in hatchling sex ratio being able to be maintained at half of the sites. We also calculated the phenological shifts that would be required (both backward for an earlier shift in nesting and forward for a later shift) to keep up with present-day incubation temperatures, hatching success rates, and sex ratios. The required shifts backward in nesting for incubation temperatures ranged from -20 to -191 days, whereas the required shifts forward ranged from +54 to +180 days. However, for half of the sites, no matter the shift the median incubation temperature will always be warmer than the 75th percentile of current ranges. Given that phenological shifts will not be able to ameliorate predicted changes in temperature, hatching success and sex ratio at most sites, turtles may need to use other adaptive responses and/or there is the need to enhance sea turtle resilience to climate warming., (© 2023 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

Longitudinal data sets for population abundance are essential for studies of imperiled organisms with long life spans or migratory movements, such as marine turtles. Population status trends are crucial for conservation managers to assess recovery effectiveness. A direct assessment of population growth is the enumeration of nesting numbers and quantifying nesting attempts (successful nests/unsuccessful attempts) and emergence success (number of hatchlings leaving the nest) because of the substantial annual variations due to nest placement, predation, and storm activity. We documented over 133,000 sea turtle crawls for 50.9 km of Florida Gulf of Mexico coastline from 1982 to 2021 for a large loggerhead turtle nesting aggregation and a recovering remnant population of green sea turtles. Over time both species have emerged to nest significantly earlier in the year and green sea turtle nesting seasons have extended. Nest counts and hatchling production for both species have significantly increased, but the rate of emergence success of hatchlings leaving nests has not changed for loggerheads and has declined for green sea turtles. Sea level rise and coastal developments undoubtedly influence coastal habitats in the long-term, impacting nest site selection and potential recruitment from the loss of emerged hatchlings. However, the present indications for steady Gulf of Mexico recovery of loggerhead and green sea turtles counter findings of the Florida Atlantic coasts. This study indicates that effective conservation practices can be detected within time scales of 1-2 turtle generations., (© 2023. Springer Nature Limited.)

Conservation of migratory species exhibiting wide-ranging and multidimensional behaviors is challenged by management efforts that only utilize horizontal movements or produce static spatial-temporal products. For the deep-diving, critically endangered eastern Pacific leatherback turtle, tools that predict where turtles have high risks of fisheries interactions are urgently needed to prevent further population decline. We incorporated horizontal-vertical movement model results with spatial-temporal kernel density estimates and threat data (gear-specific fishing) to develop monthly maps of spatial risk. Specifically, we applied multistate hidden Markov models to a biotelemetry data set (n = 28 leatherback tracks, 2004-2007). Tracks with dive information were used to characterize turtle behavior as belonging to 1 of 3 states (transiting, residential with mixed diving, and residential with deep diving). Recent fishing effort data from Global Fishing Watch were integrated with predicted behaviors and monthly space-use estimates to create maps of relative risk of turtle-fisheries interactions. Drifting (pelagic) longline fishing gear had the highest average monthly fishing effort in the study region, and risk indices showed this gear to also have the greatest potential for high-risk interactions with turtles in a residential, deep-diving behavioral state. Monthly relative risk surfaces for all gears and behaviors were added to South Pacific TurtleWatch (SPTW) (https://www.upwell.org/sptw), a dynamic management tool for this leatherback population. These modifications will refine SPTW's capability to provide important predictions of potential high-risk bycatch areas for turtles undertaking specific behaviors. Our results demonstrate how multidimensional movement data, spatial-temporal density estimates, and threat data can be used to create a unique conservation tool. These methods serve as a framework for incorporating behavior into similar tools for other aquatic, aerial, and terrestrial taxa with multidimensional movement behaviors., (© 2023 The Authors. Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology.)

Fisheries bycatch is a critical threat to sea turtle populations worldwide, particularly because turtles are vulnerable to multiple gear types. The Canary Current is an intensely fished region, yet there has been no demographic assessment integrating bycatch and population management information of the globally significant Cabo Verde loggerhead turtle (Caretta caretta) population. Using Boa Vista island (Eastern Cabo Verde) subpopulation data from capture-recapture and nest monitoring (2013-2019), we evaluated population viability and estimated regional bycatch rates (2016-2020) in longline, trawl, purse-seine, and artisanal fisheries. We further evaluated current nesting trends in the context of bycatch estimates, existing hatchery conservation measures, and environmental (net primary productivity) variability in turtle foraging grounds. We projected that current bycatch mortality rates would lead to the near extinction of the Boa Vista subpopulation. Bycatch reduction in longline fisheries and all fisheries combined would increase finite population growth rate by 1.76% and 1.95%, respectively. Hatchery conservation increased hatchling production and reduced extinction risk, but alone it could not achieve population growth. Short-term increases in nest counts (2013-2021), putatively driven by temporary increases in net primary productivity, may be masking ongoing long-term population declines. When fecundity was linked to net primary productivity, our hindcast models simultaneously predicted these opposing long-term and short-term trends. Consequently, our results showed conservation management must diversify from land-based management. The masking effect we found has broad-reaching implications for monitoring sea turtle populations worldwide, demonstrating the importance of directly estimating adult survival and that nest counts might inadequately reflect underlying population trends., (© The Authors. Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology.)

Drifting in large numbers, jellyfish often interfere in the operation of nearshore electrical plants, cause disturbances to marine recreational activity, encroach upon local fish populations, and impact food webs. Understanding the dynamic mechanisms behind jellyfish behavior is of importance in order to create migration models. In this work, we focus on the small-scale dynamics of jellyfish and offer a novel method to accurately track the trajectory of individual jellyfish with respect to the water current. The existing approaches for similar tasks usually involve a surface float tied to the jellyfish for location reference. This operation may induce drag on the jellyfish, thereby affecting its motion. Instead, we propose to attach an acoustic tag to the jellyfish's bell and then track its geographical location using acoustic beacons, which detect the tag's emissions, decode its ID and depth, and calculate the tag's position via time-difference-of-arrival acoustic localization. To observe the jellyfish's motion relative to the water current, we use a submerged floater that is deployed together with the released tagged jellyfish. Being Lagrangian on the horizontal plane while maintaining an on-demand depth, the floater drifts with the water current; thus, its trajectory serves as a reference for the current's velocity field. Using an acoustic modem and a hydrophone mounted to the floater, the operator from the deploying boat remotely changes the depth of the floater on-the-fly, to align it with that of the tagged jellyfish (as reported by the jellyfish's acoustic tag), thereby serving as a reference for the jellyfish's 3D motion with respect to the water current. We performed a proof-of-concept to demonstrate our approach over three jellyfish caught and tagged in Haifa Bay, and three corresponding floaters. The results present different dynamics for the three jellyfish, and show how they can move with, and even against, the water current., (© 2023. Springer Nature Limited.)

Estimating mortality of sea turtles incidentally captured in fishing gear is essential to understanding fishery impacts on sea turtle populations. Loggerhead turtles (Caretta caretta) are a component of bycatch in pelagic longline fisheries, including those operating in Atlantic Canada. In this study, we used pop-up satellite archival tags (PSATs) attached to 62 loggerhead turtles incidentally hooked in Atlantic Canadian shallow-set pelagic longline gear (2012-2018) to estimate associated post-release survival. Consistent with conventional fishing practices, hooks were not removed from turtles prior to release. Analysis of diving behaviour, ocean temperature, and ambient light level was used to assign fates to turtles. Post-release survival was calculated using the Kaplan-Meier estimator with right censoring. Based on this method, the annual survival probability of an individual loggerhead post-release is 0.877 ± SE 0.052. While it is commonly assumed that hook location is an important variable in predicting fates of turtles after release, there was no difference in survival of deep-hooked (swallowed hook) versus shallow-hooked turtles. These results indicate higher survivorship among hooked loggerheads captured in shallow-set pelagic longline gear than prevailing wisdom and suggest that at least some of the population impacts on loggerhead turtles conventionally attributed to pelagic longline interactions may be linked to other threats. [ABSTRACT FROM AUTHOR]

Organisms release and detect molecules for defense, reproduction, feeding strategies and finding suitable habitats. For some migratory species, homing behavior could be related to the recognition of their home chemical fingerprint made of an assemblage of molecules from their habitat. In the marine realm, the functioning of ecosystems such as underwater caves largely depends on trophic interactions between the caves and the outside environment. A key feature of these interactions relies on the circadian migration of small crustaceans (Mysida) from the cave habitat to the open sea. Recently, it has been hypothesized that these migrations could involve chemical mediation. Behavioral experiments using a two-choice system have shown that cave mysids significantly detect cave seawater rather than a control water from the open sea. Here, we used the same experimental system to investigate habitat recognition by two populations of the cave mysid Hemimysis margalefi. Both populations were submitted to a choice between three distinct cave seawaters vs. a control seawater. Additionally, experiments tested the water preference of a non-cave mysid species (Leptomysis sp.) between control and cave seawaters. To evaluate whether the choice of mysids was influenced by chemical cues from conspecifics, a complementary experiment on H. margalefi was conducted. Results demonstrated that each studied mysids population significantly recognizes the water of its own home habitat, and that this behavior is not influenced by the occurrence of H. margalefi's exudates. Mass spectrometry-based metabolomic analyses revealed that each cave seawater had a specific chemical fingerprint with only a few reproducibly detected signals belonging to different chemical classes: peptides, alkaloids, fatty acids, steroids but also inorganic molecules. Organic pollutants have also been reproducibly detected. Among the detected compounds, one oxylipin derivative and one peptide could be considered as chemical markers of the cave ecosystem. Therefore, we postulate that the chemical seascape of each cave participates to mysid circadian migrations which are analogous to a daily-based homing behavior. [ABSTRACT FROM AUTHOR]

Hatching synchronisation is widespread in oviparous taxa. It has been demonstrated that many species use sounds to coordinate synchronous hatching, being widespread among archosaurs (birds and crocodilians). Recent studies have shown that some turtle species produce vocalisations from within the egg, but the role of this behaviour in synchronising hatch is untested. The small amount of information about sound production by turtle embryos, limited to a handful of closely related species, precludes any inferences based on differences in their ecology, reproductive behaviour and phylogenetic context. With the goal to investigate if coordinated synchronous behaviour is mediated by within‐egg vocalisations in turtles, we recorded clutches from six different turtle species. The selected animals present different ecological and reproductive niches and belong to distinct phylogenetic lineages at the family level. We aimed to understand: (1) what is the phylogenetic distribution of within‐egg vocal behaviour among turtles; (2) if asynchronous turtle species vocalise from within the egg; (3) if clutch size influences synchronous behaviour and (4) if within‐egg turtle calls follow any phylogenetic signal. The new evidence provides light to the current knowledge about synchronous behaviour and within‐egg calls, challenging previous hypothesis that within‐egg sounds are accidentally produced as side‐effects of other behaviours. [ABSTRACT FROM AUTHOR]

Freshwater jellyfish (= limnic medusa‐budding hydrozoans, FWJ) are a small group of cnidarians found on all continents except Antarctica in temperate to tropical latitudes. Members of this group belong primarily to three genera: Astrohydra, Craspedacusta, and Limnocnida. While Astrohydra and Limnocnida are typically restricted to the islands of Japan, Africa, and the Indian subcontinent, one species or potential species complex, Craspedacusta sowerbii, became globally invasive. Despite research going back about one‐and‐a‐half centuries, little is known about their phylogeny and ecology compared to marine jellyfish. Recent species distribution modelling, however, showed that by 2050, C. sowerbii will potentially extend their distribution ranges due to global warming to high‐latitude ecosystems and be present (medusa stage) for an extended time in the seasonal limnic production cycle. An increase in their relative ecological importance with temporal and spatial spreading is hypothesised. Only recently, it has been shown that the trophic roles of polyps and medusae and their prey overlap with other ecosystem members. In addition, medusa behaviour may cause trophic cascades and alter vertical nutrient distributions. However, polyps and other benthic life cycle stages are understudied. In globally, changing freshwater ecosystems that may become more accommodating for FWJ, an improved understanding of their population biology and ecosystem ecology is urgently needed. In this integrative review, we, therefore, explore reasons for the hampered historical research progress, contrast developments with those of marine cnidarians, compile and publish alongside an extensive and unprecedented literature database, and formulate avenues for future directions in FWJ research. [ABSTRACT FROM AUTHOR]

Natural selection favors individuals with the highest inclusive fitness (i.e., total number of descendants). In cases where one sex is more productive, one or both parents may maximize their inclusive fitness by investing in the offspring of the more prolific sex. Such preferential production can lead to skewed sex ratios at various life history stages, including at birth, resulting in secondary sex ratio bias. Several competing hypotheses have been proposed to explain observed variation in secondary sex ratios including Fisher's frequency dependence and two hypotheses related to maternal condition: Trivers–Willard and the local resource hypotheses. Although it has been shown that maternal condition can influence the number of offspring produced in white‐tailed deer, there is no consensus as to which of the hypotheses drives sex ratio bias in wild populations. Using a spatiotemporally extensive dataset of pregnant white‐tailed deer from Mississippi, USA, we examined fetal sex ratio in relation to the Fisherian frequency‐dependence hypothesis and hypotheses related to maternal condition. While there was a male‐sex ratio bias in pregnant females that reduced in intensity with the number of offspring, there was no support for condition‐related hypotheses. Instead, secondary sex ratios for white‐tailed deer in Mississippi were nearly consistent with Fisherian frequency dependence. Our findings add to the body of literature on secondary sex biases in white‐tailed deer and help inform sex bias ratios for a southern population of a cervid of management importance in the US. [ABSTRACT FROM AUTHOR]

Natural populations that are rare, cryptic or inaccessible provide a monumental challenge to monitoring, as adequate data are extremely difficult to collect. Surveys often encompass only a small portion of a population's range due to difficult terrain or inclement weather, especially for populations with extensive ranges. Thus, to maximise encounters, sampling efforts may be largely opportunistic or biased to accessible areas. The resulting sparse and spatially biased data may be difficult to model, standardise across years and incorporate into an assessment or management framework. However, in many monitoring programs, there are usually multiple threads of data that, though each may have its own limitations, can be synthesised to reveal important ecological processes.Here, we demonstrate a simple technique to incorporate two additional streams of data on the same population, telemetry and survey effort data, into capture‐recapture analyses to address spatiotemporal sampling bias using simulated data. Utilisation distributions (UDs) computed from telemetry data are overlaid with UDs of survey efforts, providing an 'effort by animal space use' overlap covariate for modelling detection in a Jolly–Seber open population model.Using simulated data, we found that our method resulted in more accurate and precise estimates of abundance than traditional capture‐recapture models. We then applied this method to a 16 year photo‐identification capture‐recapture dataset (n = 143 individuals) along with telemetry data (n = 44 satellite tag deployments) collected from the endangered population of false killer whales resident to the main Hawaiian Islands.Incorporating space use and effort into this analysis improved precision of abundance estimates relative to previous modelling endeavours. [ABSTRACT FROM AUTHOR]

Goose-beaked whales (Ziphius cavirostris) are deep-diving cetaceans known for their elusive nature and specialized foraging behavior. In 2019 and 2020, six telemetry tags were deployed on these whales in Southern California, resulting in 395 h of acoustic and diving data. Foraging dives were manually identified by the presence of echolocation pulses and buzzes, and generalized additive models assessed factors influencing foraging behavior. The median bathymetric depth at foraging sites was 1,419 m (IQR = 359), and the maximum dive depth was highly correlated with bathymetry depth. Individuals started echolocating on descent at a median depth of 410 m (IQR = 74); pulses were not observed shallower than 292 m. Echolocation ceased during the bottom phase for 81.6% of dives, at a median depth of 1,265 m (IQR = 472); pulses were not observed shallower than 587 m on ascent. The median depth of buzzes was 1,215 m (IQR = 479) with 63% occurring during the bottom phase. Deeper dives correlated with longer durations of diving and echolocation, greater echolocation end depths, and wider bottom phase echolocation depth inter-quartile range. The median difference between dive depth and bottom phase median echolocation depth was 98.3 m (IQR = 48.5), suggesting whales in this region forage in a narrow band close to the seafloor. In the San Nicolas Basin, individuals exhibited longer echolocation durations, produced more pulses, and started and ended echolocating at greater depths compared to adjacent regions. These records validate and expand upon previous studies, providing insights into factors influencing foraging behavior in an area with high anthropogenic disturbance. [ABSTRACT FROM AUTHOR]

Male sperm whales (Physeter macrocephalus) are known to interact with and depredate from commercial longline fishing vessels targeting sablefish (Anoplopoma fimbria) in the Gulf of Alaska (GOA). This study aims to better understand their movement patterns and diving behavior in this region, and in relation to depredation behavior. Between 2007 and 2016 a total of 33 satellite tags were deployed on sperm whales interacting with fishing vessels in the eastern GOA. A subset of these tags also collected dive characteristics. We used state space models to interpolate hourly positions from tags and estimate behavioral state from 29 usable tag records, 14 of which had associated dive information. Whales exhibited slower horizontal movement (1.4 km/hr) within GOA waters compared to south of the GOA (5.5 km/hr), indicating tagged whales sped up when they left the region. Behavioral states indicated primarily foraging behavior (82% of locations) in the GOA and primarily transiting behavior (74% of locations) when whales left the GOA. Dive data showed average (± Standard Deviation) maximum dive depths of 396 m (± 166), and dive durations of 32 min (± 9). Generalized additive models indicated that dives were significantly deeper and longer during the daytime than dawn, dusk, or nighttime, and dives were significantly deeper and shorter during quarter moons, when tidal currents are weakest. Maximum dive depth decreased in areas of higher sablefish CPUE, suggesting a potential link between the sablefish fishery and depredation behavior. As seafloor depth increased, up to 800 m, dives became deeper, indicating that whales were likely targeting both bathypelagic and mesopelagic prey. This highlights the importance of the GOA continental slope as a foraging ground for male sperm whales. This enhanced understanding of sperm whale foraging ecology informs management and conservation efforts in high latitude foraging grounds. [ABSTRACT FROM AUTHOR]

In 2017, the Chilean government through the Chilean Economic Development Agency (CORFO) (an agency under the Ministry of Economy) launched a public call for the execution of a Technological Program to adopt, adapt, and/or developing enabling technologies for the development of Ocean Aquaculture in places with high-energy (strong waves, winds and/or currents). The consortium of companies, technology centers, and universities led by Ecosea Farming (Ecosea), focused its efforts on aspects related to structural engineering, mooring systems, sensors, Internet of Things (IoT), and other integral components, as well as essential aspects of regulation and standards. On this last topic, intensive collaborative work was carried out between the technical teams of the Andrés Bello University, the Undersecretariat of Fisheries and Aquaculture (Subpesca), the National Fisheries and Aquaculture Service (Sernapesca), and CORFO, with the aim of gathering relevant information from international experience, and establishing the main differences between aquaculture traditionally developed in the fjords, coast, estuaries, and inland sea of southern Chile and aquaculture in the high seas - a practice not yet clearly defined and still indistinctly known as offshore or open ocean aquaculture. This document summarizes the main findings obtained and can be a useful guide for future experiences in other countries with important aquaculture developments. [ABSTRACT FROM AUTHOR]