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We are in the midst of a revolution in satellite technology, with the rapid development and advancement of small satellites (or SmallSats, i.e., satellites

20 pages, 3 tables, 5 figures.-- Samantha Andrzejaczek ... et al.-- Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC), Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements, Data analysis was funded by the Bertarelli Foundation through the Marine Science program through grants to D.J.C., B.A.B., and S.A. D.J.C. is also funded through Research England, UK. S.A. and B.A.B. thank the Moore Foundation and the Packard Foundation. F.G.-M. thanks the Instituto Politecnico Nacional for fellowships (COFAA, EDI). S.B.W. thanks funding from the Darwin Initiative (DPLUS046). A.D.M.D. acknowledges funding from the Research and Conservation Budget at Georgia Aquarium, including philanthropic gifts from several anonymous donors. K.F. acknowledges funding from the Rolex Awards for Enterprise and the Whitley Fund for Nature

Mapping and predicting the potential risk of fishing activities to large marine protected areas (MPAs), where management capacity is low but fish biomass may be globally important, is vital to prioritizing enforcement and maximizing conservation benefits. Drifting fish aggregating devices (dFADs) are a highly effective fishing method employed in purse seine fisheries that attract and accumulate biomass fish, making fish easier to catch. However, dFADs are associated with several negative impacts, including high bycatch rates and lost or abandoned dFADs becoming beached on sensitive coastal areas (e.g., coral reefs). Using Lagrangian particle modeling, we determined the potential transit of dFADs in a large MPA around the Chagos Archipelago in the central Indian Ocean. We then quantified the risk of dFADs beaching on the archipelago's reefs and atolls and determined the potential for dFADs to pass through the MPA, accumulate biomass while within, and export it into areas where it can be legally fished (i.e., transit). Over one‐third (37.51%) of dFADs posed a risk of either beaching or transiting the MPA for >14 days, 17.70% posed a risk of beaching or transiting the MPA for >30 days, and 13.11% posed a risk of beaching or transiting the MPA for >40 days. Modeled dFADs deployed on the east and west of the perimeter were more likely to beach and have long transiting times (i.e., posed the highest risk). The Great Chagos Bank, the largest atoll in the archipelago, was the most likely site to be affected by dFADs beaching. Overall, understanding the interactions between static MPAs and drifting fishing gears is vital to developing suitable management plans to support enforcement of MPA boundaries and the functioning and sustainability of their associated biomass., Article impact statement: Left unchecked, drifting fish aggregation devices could reduce the efficacy of static marine protected areas.

A wide array of technologies are available for gaining insight into the movement of wild aquatic animals. Although acoustic telemetry can lack the fine‐scale spatial resolution of some satellite tracking technologies, the substantially longer battery life can yield important long‐term data on individual behavior and movement for low per‐unit cost. Typically, however, receiver arrays are designed to maximize spatial coverage at the cost of positional accuracy leading to potentially longer detection gaps as individuals move out of range between monitored locations. This is particularly true when these technologies are deployed to monitor species in hard‐to‐access locations.Here, we develop a novel approach to analyzing acoustic telemetry data, using the timing and duration of gaps between animal detections to infer different behaviors. Using the durations between detections at the same and different receiver locations (i.e., detection gaps), we classify behaviors into “restricted” or potential wider “out‐of‐range” movements synonymous with longer distance dispersal. We apply this method to investigate spatial and temporal segregation of inferred movement patterns in two sympatric species of reef shark within a large, remote, marine protected area (MPA). Response variables were generated using network analysis, and drivers of these movements were identified using generalized linear mixed models and multimodel inference.Species, diel period, and season were significant predictors of “out‐of‐range” movements. Silvertip sharks were overall more likely to undertake “out‐of‐range” movements, compared with gray reef sharks, indicating spatial segregation, and corroborating previous stable isotope work between these two species. High individual variability in “out‐of‐range” movements in both species was also identified.We present a novel gap analysis of telemetry data to help infer differential movement and space use patterns where acoustic coverage is imperfect and other tracking methods are impractical at scale. In remote locations, inference may be the best available tool and this approach shows that acoustic telemetry gap analysis can be used for comparative studies in fish ecology, or combined with other research techniques to better understand functional mechanisms driving behavior., Financial and logistical constraints may lead to imperfect in‐field acoustic receiver array designs which can result in acoustic telemetry data with long detection gaps. We present a novel gap analysis of telemetry data to help infer differential movement and space use patterns where acoustic coverage is imperfect and other tracking methods impractical

Mobulid populations are declining on a global scale as a result of both targeted fisheries and indirect anthropogenic threats. In order to implement effective conservation strategies for species of this taxa, it is crucial that movement patterns at a range of spatiotemporal scales are defined. To gain insight into such patterns, we deployed a combination of acoustic (n = 21) and satellite (n = 12) tags on reef manta rays Mobula alfredi in the British Indian Ocean Territory Marine Protected Area (BIOT MPA) annually from 2013 through 2016. An extensive array of acoustic receivers (n = 52) were deployed across the archipelago to record the movements of mantas throughout the MPA. Data revealed large individual variation in horizontal movement patterns, ranging from high local site fidelity (200 km) around the entire MPA. Depth time-series data recorded vertical movement patterns consistent with other epipelagic elasmobranch species, including oscillatory diving and deep dives to greater than 500 m. Though no individuals were directly recorded departing the MPA throughout the study, the gaps in detections and estimated travel speeds documented here indicate that movement of individuals outside of the BIOT MPA cannot be discounted. Collectively, our data suggests that, with effective enforcement, the current size of the BIOT MPA is providing substantial protection to its reef manta ray population. Characterization of movement patterns across ontogenetic classes, however, is required to fully characterize the spatial ecology of this species and ensure protection across all cohorts of the population.

Polychlorinated biphenyls (PCBs) are toxic, persistent, and lipophilic chemical compounds that accumulate to high levels in harbor porpoises (Phocoena phocoena) and other cetaceans. It is important to monitor PCBs in wildlife, particularly in highly exposed populations to understand if concentrations are declining and how levels relate to toxicological thresholds and indices of health like infectious disease mortality. Here we show, using generalized additive models and tissue samples of 814 U.K.-stranded harbor porpoises collected between 1990 and 2017, that mean blubber PCB concentrations have fallen below the proposed thresholds for toxic effects. However, we found they are still associated with increased rates of infectious disease mortality such that an increase in PCB blubber concentrations of 1 mg kg-1 lipid corresponds with a 5% increase in risk of infectious disease mortality. Moreover, rates of decline and levels varied geographically, and the overall rate of decline is slow in comparison to other pollutants. We believe this is evidence of long-term preservation in the population and continued environmental contamination from diffuse sources. Our findings have serious implications for the management of PCB contamination in the U.K. and reinforce the need to prevent PCBs entering the marine environment to ensure that levels continue to decline.

Natural history documentary films can be a powerful tool for wildlife conservation, providing an accessible means to increase public knowledge of the natural world. There has been an increasing focus in documentary films on the threats to biodiversity in recent years that has positively aided conservation efforts. However, potential ethical and welfare implications of natural history film making are often overlooked. Here, we consider the design and impact of the narratives used and the filming methods employed in natural history film making and their potential implications for conservation. Although these programmes are often lauded for their cinematography, filming techniques and practices should satisfy high ethical standards and should be evaluated to assess disturbance caused to wildlife and any associated negative behavioural and physiological impacts. This evaluation should include the direct impact of the filming, as well as considering the risk of viewers replicating human-wildlife encounters they see on film. Trends towards the use of highly dramatized storytelling, anthropomorphism and the inclusion of inaccurate information should also be addressed. Although some production companies have filming guidelines in place, this is not standard industry practice. Natural history films are an important means of educating and enthusing people about nature and its conservation; however, it is vital that films are made responsibly. To facilitate this discussion, we propose recommendations, including standardised industry-wide guidelines, codes of conduct and independent ethical reviews, for natural history film makers to mitigate and avoid negative impacts.

We report the first mitochondrial genome sequences for the gray reef shark, Carcharhinus amblyrhynchos. Two specimens from the British Indian Ocean Territory were sequenced independently using two different next generation sequencing methods, namely short read sequencing on the Illumina HiSeq and long read sequencing on the Oxford Nanopore Technologies’ MinION sequencer. The two sequences are 99.9% identical and are 16,705 base pairs (bp) and 16,706 bp in length. The mitogenome contains 22 tRNA genes, two rRNA genes, 13 protein-coding genes and two non-coding regions; the control region and the origin of light-strand replication (OL).

Stable-isotope analyses (δ13 C, δ15 N and δ34 S) of multiple tissues (fin, muscle, red blood cells and plasma), revealed ontogenetic shifts in resource use by grey reef sharks Carcharhinus amblyrhynchos and resource partitioning with silvertip sharks Carcharhinus albimarginatus within the British Indian Ocean Territory marine protected area (MPA). Resource partitioning varied temporally, with C. albimarginatus feeding on more pelagic prey during October to January, potentially attributable to an influx of pelagic prey from outside the MPA at that time. Reef sharks may therefore be affected by processes outside an MPA, even if the sharks do not leave the MPA.

Polychlorinated biphenyls (PCBs) are highly toxic and persistent aquatic pollutants that are known to bioaccumulate in a variety of marine mammals. They have been associated with reduced recruitment rates and population declines in multiple species. Evidence to date documents effects of PCB exposures on female reproduction, but few studies have investigated whether PCB exposure impacts male fertility. Using blubber tissue samples of 99 adult and 168 juvenile UK-stranded harbour porpoises (Phocoena phocoena) collected between 1991 and 2017, here we show that PCBs exposures are associated with reduced testes weights in adults with good body condition. In animals with poor body condition, however, the impact of PCBs on testes weights was reduced, conceivably due to testes weights being limited by nutritional stress. This is the first study to investigate the relationship between PCB contaminant burden and testes weights in cetaceans and represents a substantial advance in our understanding of the relationship between PCB exposures and male reproductive biology in cetaceans. As testes weight is a strong indicator of male fertility in seasonally breeding mammals, we suggest the inclusion of such effects in population level impact assessments involving PCB exposures. Given the re-emergent PCB threat our findings are globally significant, with potentially serious implications for long-lived mammals. We show that more effective PCB controls could have a substantial impact on the reproductive health of coastal cetacean species and that management actions may need to be escalated to ensure adequate protection of the most vulnerable cetacean populations. Defra; Natural Environment Research Council (NERC) grant NE/L002485/1; Bertarelli Foundation through the Bertarelli Programme in Marine Science; partially funded by NERC grant NE/S000100/1 supporting the ChemPop project.

Given the recent trend towards establishing very large marine protected areas (MPAs) and the high potential of these to contribute to global conservation targets, we review outcomes of the last decade of marine conservation research in the British Indian Ocean Territory (BIOT), one of the largest MPAs in the world. The BIOT MPA consists of the atolls of the Chagos Archipelago, interspersed with and surrounded by deep oceanic waters. Islands around the atoll rims serve as nesting grounds for sea birds. Extensive and diverse shallow and mesophotic reef habitats provide essential habitat and feeding grounds for all marine life, and the absence of local human impacts may improve recovery after coral bleaching events. Census data have shown recent increases in the abundance of sea turtles, high numbers of nesting seabirds and high fish abundance, at least some of which is linked to the lack of recent harvesting. For example, across the archipelago the annual number of green turtle clutches (Chelonia mydas) is ~ 20,500 and increasing and the number of seabirds is ~ 1 million. Animal tracking studies have shown that some taxa breed and/or forage consistently within the MPA (e.g. some reef fishes, elasmobranchs and seabirds), suggesting the MPA has the potential to provide long-term protection. In contrast, post-nesting green turtles travel up to 4000 km to distant foraging sites, so the protected beaches in the Chagos Archipelago provide a nesting sanctuary for individuals that forage across an ocean basin and several geopolitical borders. Surveys using divers and underwater video systems show high habitat diversity and abundant marine life on all trophic levels. For example, coral cover can be as high as 40–50%. Ecological studies are shedding light on how remote ecosystems function, connect to each other and respond to climate-driven stressors compared to other locations that are more locally impacted. However, important threats to this MPA have been identified, particularly global heating events, and Illegal, Unreported and Unregulated (IUU) fishing activity, which considerably impact both reef and pelagic fishes.

The term “Anthropocene” has been suggested as the current epoch (denoting the current geological age) and is viewed as the period where human-based activity is the dominant influence on climate and the environment (Lewis and Maslin, 2015). Arguably, one of the most prevalent and visible effects of this anthropogenic activity has manifested in the equatorial tropics—where coral reef ecosystems have suffered alarming declines (Pandolfi et al., 2003; Hughes et al., 2017). For example, recent increases in mass bleaching events brought about by prolonged periods of elevated sea surface temperatures highlight a worrying trend, with predictions that over half of reefs will experience annual severe bleaching before 2050 (van Hooidonk et al., 2016). For this reason, coral reefs have often been referred to as “canaries in the coal mine” for the marine biome. Yet reefs continue to be crucial sources of food, protection, livelihoods, and cultural identity for many people around the world (Teh et al., 2013; Hicks and Cinner, 2014; Lau et al., 2019). It is therefore critical that the link between healthy reefs, food security, and sustainable community livelihoods is maintained into the future. This Research Topic represents the proceedings for the European Coral Reef Symposium (ECRS), which took place 13th–15th December, 2017 in Oxford, UK. ECRS was organised by the Reef Conservation United Kingdom (RCUK) committee, in association with the Zoological Society of London (ZSL), University of Oxford, and the International Coral Reef Society (ICRS). Over 550 coral reef scientists and conservationists joined the meeting for a series of talks, posters, and workshops. In addition to the papers in this Research Topic, ECRS provided a platform for many other coral reef-related events and outputs. For example, the symposium hosted the European launch of the 2018 International Year of the Reef on the 13th December 2017, and several of the workshops produced published outputs (e.g., Turner et al., 2019). In this editorial, we provide a brief history of RCUK—charting the course from inception in 1997 through to ECRS in 2017—including our sustainable conferencing efforts and commitments to diversity and inclusion. We strongly believe that all conferences should carefully consider sustainability, diversity, and inclusion and we hope our efforts will inspire and encourage other conference organisers to do the same. We then introduce the globally relevant coral reef science and conservation that has been presented at RCUK meetings and provide an overview of the papers submitted to this Research Topic. We close by highlighting our vision for RCUK into the future—and lay out how this can be applied to the upcoming Frontiers Spotlight Conference on Coral Reefs.

The efficacy of large marine protected areas (MPA) for the conservation of mobile pelagic species is widely debated. Here, we quantified spatial and temporal trends in standardized catch per unit effort (CPUE) of two target pelagic species, yellowfin (Thunnus albacares) and bigeye tuna (Thunnus obesus) in the Indian Ocean to analyze the impact of the British Indian Ocean Territory (BIOT) MPA's creation in 2010. We applied generalized additive mixed effects models to historical BIOT longline fishery logbooks and official catch and effort statistics from the Indian Ocean Tuna Commission (IOTC) to standardize CPUEs and to evaluate long-term trends and distribution patterns across the equatorial Indian Ocean. We find that trends in population indices from within BIOT prior to the MPA's establishment mirror those of the wider Indian Ocean. We also suggest that there may be behavioral plasticity within the yellowfin tuna stock, with some individuals possibly undertaking alternative migration patterns or exhibiting residency behavior within BIOT. Yet, we find no direct evidence of any improvement in standardized CPUE indices of either species in the area surrounding the BIOT MPA, nearly 8 years after its establishment. The average size of yellowfin and bigeye tunas caught both increased after the MPA's establishment. These patterns were also evident across the equatorial Indian Ocean, suggesting that any MPA effect is in combination with other regional drivers, such as behavioral changes in the fishing fleets in response to the threat of Somali Piracy. We therefore conclude that BIOT MPA may be providing local conservation value to tunas, but it is not significant enough to halt the overall regional decline in yellowfin tuna stocks. Thus, we emphasize that large MPAs should be considered in conjunction with other fishery management regulations and wider regional processes, rather than as a silver bullet, in order to provide the conservation and management benefits needed for mobile species like tunas. Zoological Society of London; University College London Impact Award; Bertarelli Foundation through the Bertarelli Programme in Marine Science This work was funded by the Zoological Society of London, a University College London Impact Award and the Bertarelli Foundation through the Bertarelli Programme in Marine Science.

Polychlorinated biphenyls (PCBs) are toxic, persistent, and lipophilic chemical compounds that accumulate to high levels in harbor porpoises (

Background There are now a wide array of field and laboratory techniques available for gaining insight into the movement and behaviour of sharks. Although acoustic telemetry may lack the fine-scale resolution of satellite telemetry, the low cost and longer battery life make it a powerful tool for investigating elasmobranch behaviour. Here, in the absence of satellite tracking data, we develop a novel approach to analysing acoustic telemetry data, using detection gaps to infer movement patterns to and from monitored reef habitats, to investigate spatial and temporal segregation between two sympatric shark species in a large remote MPA. Methods A total of 102 grey reef and 76 silvertip sharks were fitted with long-term acoustic transmitters and tracked inside a large acoustic array of reef-based receivers in the British Indian Ocean Territory MPA, between 2014 and 2018. From the resulting dataset (768,081 movements), movements between receivers and recursive loops to the same receiver were identified. Using the durations of inter-receiver movements (i.e. detection gaps), individual behaviours were classified into ‘restricted’ or ‘wider ranging’ movements. Drivers of these movements were identified using network analysis, generalised linear mixed models and multi-model inference starting from an a priori set of explanatory variables. Results In general, silvertip sharks were more likely to undertake ‘wider ranging’ movements than grey reef sharks. ‘Wider ranging’ movements were more common at night compared to during the day, and during the wet season compared to the dry season. In addition, the difference in ‘wider ranging’ movements between the two species increased at night. These results suggest spatial segregation and temporal segregation of movements between grey reef and silvertip sharks in the region. Conclusions We present a novel analysis of detection gaps from acoustic telemetry data to infer differential movement patterns and describe how species organise in space and time. Furthermore, this approach shows that acoustic telemetry gap analysis can be used for comparative studies, or combined, with other research techniques to better understand the functional role of sharks in reef ecosystems, moving towards more informed strategies for the conservation and management of the marine environment.

The Chagos archipelago in the British Indian Ocean Territory (BIOT) has been lacking in detailed genetic studies of its chondrichthyan populations. Chondrichthyes in Chagos continue to be endangered through illegal fishing operations, necessitating species distribution and abundance studies to facilitate urgent monitoring and conservation of the species. Here, we present a complete mitochondrial genome of the Silvertip Shark, Carcharhinus albimarginatus sampled in the Chagos archipelago. The mitochondrial genome of C. albimarginatus was 16,706 bp in length and consisted of 13 protein-coding genes, 22 tRNA genes, two rRNA genes, a replication origin and a D-loop region. GC content was at 38.7% and the control region was 1,065 bp in length. We expect that mitogenomes presented here will aid development of molecular assays for species distribution studies. Overall these studies will promote effective conservation of marine ecosystemes in the BIOT.

1. Recently, several large marine protected areas (MPAs) have been established globally and it is hoped that they will aid the recovery of populations of highly-mobile, large pelagic species. Understanding the distribution of these species within MPAs is key to delivering effective management but monitoring can be challenging over such vast areas of open ocean. 2. Historical fisheries data, collected prior to reserve establishment, can provide an insight into the past distributions of target species. We investigated the 10spatial and temporal distribution of yellowfin (Thunnus albacares) and skipjack (Katsuwonus pelamis) tuna catch using logbook data from the purse seine fishery in British Indian Ocean Territory (BIOT) from 1996 to 2010, before it was established as an MPA in April 2010. 3. Generalized additive models (GAMs) were used to predict tuna presence and relative abundance from fishing records in relation to temporal and environmental variables. Significant variables included sea salinity, temperature and water velocity. 4. Predictions from the models identified a distinct hotspot for large yellowfin tuna within the MPA, and areas of high predicted relative abundance of skipjack tuna. We recommend that these areas are used as focal points from which populations can be monitored and investigations into tuna residency time can occur, so that the effectiveness of the MPA in conserving highly-mobile pelagic fish can be determined.

SCOPUS: le.j, info:eu-repo/semantics/published

Integrative and historical approach redefines shark baselines in remote coral reef ecosystems., Scientific monitoring has recorded only a recent fraction of the oceans’ alteration history. This biases our understanding of marine ecosystems. Remote coral reef ecosystems are often considered pristine because of high shark abundance. However, given the long history and global nature of fishing, sharks’ vulnerability, and the ecological consequences of shark declines, these states may not be natural. In the Chagos archipelago, one of the remotest coral reef systems on the planet, protected by a very large marine reserve, we integrated disparate fisheries and scientific survey data to reconstruct baselines and long-term population trajectories of two dominant sharks. In 2012, we estimated 571,310 gray reef and 31,693 silvertip sharks, about 79 and 7% of their baseline levels. These species were exploited longer and more intensively than previously thought and responded to fishing and protection with variable and compensatory population trajectories. Our approach highlights the value of integrative and historical analyses to evaluate large marine ecosystems currently considered pristine.

Previous blue carbon studies have focused on discrete carbon stock assessments and overarching systematic reviews which broadly speculate that it may be economically viable to incorporate mangroves into existing carbon finance platforms. There is a discernible need to test this hypothesis through case-specific investigations that determine this presumed viability in a local or regional context – at scales meaningful for policy development. The current study investigates whether the carbon values of mangrove forests on Panay Island, the Philippines, are sufficient to offset the opportunity costs of milkfish ( Chanos chanos ) aquaculture – the primary cause of mangrove deforestation in the Philippines. Profit margins associated with milkfish aquaculture are calculated through a municipality-wide survey (779±140 US$ ha −1 yr −1 ). Concurrently, the carbon stocks of two heterogeneous mangrove forests are quantified and compared. Creditable CO 2 emissions reductions are modelled under a broad range of assumptions. These emissions are valorised, and a sensitivity analysis is performed to establish the minimum price at which opportunity costs are offset across a range of methodological and accounting preferences. It is determined that carbon prices of around 5–12 US$ tCO 2 e −1 would be required to compensate landowners for their lost aquaculture profits. The implications of our findings are discussed.

Over the past 25 years it has become apparent that European eel recruitment has declined despite increased awareness and the development of protective legislation at local, national and European levels. A number of factors in both the freshwater and marine environment have been identified as potentially causing the decline, but there is little evidence how they specifically affect eel populations. There has been very little monitoring of European eel populations and therefore few robust data sets to allow long-term analysis. Eels were monitored at three sites in the Thames catchment between 2005 and 2009. At one site (River Roding) the catch per unit effort declined significantly after 2007, whilst at the other sites (River Thames and River Darent) catches were low throughout the period of the survey. Comparison of eel abundances at the River Darent caught in the present study with those caught in the mid 1980s would indicate that recruitment has declined by over 99%. The study highlights the lack of data relating to eel recruitment in the River Thames, and the UK as a whole, and supports both improved monitoring and the adoption of a precautionary approach in their management, irrespective of the causal factors for the decline.

On 1st April 2010, the British Government announced designation of the British Indian Ocean Territory – or Chagos Archipelago – as the world’s largest marine protected area (MPA). This near pristine ocean ecosystem now represents 16% of the worlds fully protected coral reef, 60% of the world’s no-take protected areas and an uncontaminated reference site for ecological studies. In addition these gains for biodiversity conservation, the Chagos/BIOT MPA also offers subsidiary opportunities to act as a fisheries management tool for the western Indian Ocean, considering its size and location. While the benefits of MPAs for coral-reef dwelling species are established, there is uncertainty about their effects on pelagic migratory species. This paper reviews the increasing body of evidence to demonstrate that positive, measurable reserve effects exist for pelagic populations and that migratory species can benefit from no-take marine reserves.