ORCID Profile
0000-0003-2729-3811
Current Organisations
Lancaster University
,
The Zoological Society of London
,
University of Leeds
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Publisher: Elsevier BV
Date: 10-2023
Publisher: Oxford University Press (OUP)
Date: 03-11-2011
Abstract: Multiple paternity (MP) has been demonstrated in a variety of sharks, although its prevalence and the number of sires per litter vary considerably among species. To date, such analyses have focused on viviparous species that possess only part of the wide spectrum of reproductive strategies developed in elasmobranchs. We analyzed MP in an oviparous species, the small-spotted catshark (Scyliorhinus canicula). In total, 150 neonates originating from 13 different mothers were genotyped using 12 microsatellite loci. MP was commonplace, with progeny from 92% of females sired by multiple males. This result is consistent with the reproductive biology of the species, particularly its protracted breeding season and potential for long-term sperm storage. The significance of these findings is discussed in light of small-spotted catshark behavior, which suggests that the cost of avoiding mating attempts initiated by males may be high and is therefore supportive of convenience polyandry as an explanation for MP. Eggs were followed from the time they were laid to when they hatched, offering a rare opportunity to investigate juvenile development in more detail.
Publisher: Wiley
Date: 10-2021
DOI: 10.1002/RSE2.239
Abstract: 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 kg). Here, we review the opportunities and challenges that such technology might afford in the field of conservation and ecology. SmallSat constellations may yield higher resolutions than those that are currently available to scientists and practitioners, increasing opportunities to improve environmental‐monitoring and animal‐tracking capabilities. They may cut access costs to end users, by reducing operational costs and bringing increased competition to the existing market. Their greater flexibility and affordability may moreover enable the development of bespoke constellations for specific conservation and ecological applications, and provide greater interoperability with ground‐based sensors, such as tracking devices and camera traps. In addition, SmallSats may serve as cost‐effective research and development platforms for new components and products. Combined, these benefits could significantly improve our ability to monitor threats to the environment as they unfold, while enhancing our understanding of animal ecology and ecosystem dynamics. However, significant hardware and software developments are required before such technology is able to produce, process and handle reliable and cost‐effective data, and the initial research and development costs still represent a major challenge. Further, we argue that much remains to be done to ensure these new data products become accessible, equitable and sustainable.
Publisher: Springer Science and Business Media LLC
Date: 06-2013
DOI: 10.1038/S41586-019-1444-4
Abstract: Effective ocean management and the conservation of highly migratory species depend on resolving the overlap between animal movements and distributions, and fishing effort. However, this information is lacking at a global scale. Here we show, using a big-data approach that combines satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space-use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively), and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of fishing effort in marine areas beyond national jurisdictions (the high seas). Our results demonstrate an urgent need for conservation and management measures at high-seas hotspots of shark space use, and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real-time, dynamic management.
Publisher: Springer Science and Business Media LLC
Date: 14-10-2020
Publisher: Elsevier BV
Date: 04-2022
Publisher: Frontiers Media SA
Date: 28-03-2019
Publisher: Springer Science and Business Media LLC
Date: 28-02-2022
DOI: 10.1038/S42003-022-03138-W
Abstract: Despite our critical dependence on aquatic wildlife, we lack a complete understanding of the drivers of population stability and structure for most fish species. Social network analysis has been increasingly used to investigate animal societies as it explicitly links in idual decision-making to population-level processes and demography. While the study of social structure is of great ecological interest, it is also potentially important for species of economic value or of conservation concern. To date however, there has been little focus on how social processes are likely to influence the conservation of fish populations. Here we identify applications for how a social network approach can help address broad fish conservation themes such as population structure, biological invasions or fisheries management. We discuss the burgeoning opportunities offered and challenges still faced by current technologies to integrate social network approaches within fish conservation.
Publisher: Cold Spring Harbor Laboratory
Date: 29-08-2019
DOI: 10.1101/749085
Abstract: Animal movement patterns are increasingly analysed as spatial networks. Currently, structures of complex movements are typically represented as a single-layer (or monoplex) network. However, aggregating in idual movements, to generate population-level inferences, considerably reduces information on how in idual or species variability influences spatial connectivity and thus identifying the mechanisms driving network structure remains difficult. Here, we propose incorporating the recent conceptual advances in multilayer network analyses with the existing movement network approach to improve our understanding of the complex interaction between spatial and/or social drivers of animal movement patterns. Specifically, we explore the application and interpretation of this framework using an empirical ex le of shark movement data gathered using passive remote sensors in a coral reef ecosystem. We first show how aggregating in idual movement networks can lead to the loss of information, potentially misleading our interpretation of movement patterns. We then apply multilayer network analyses linking in idual movement networks (i.e. layers) to the probabilities of social contact between in iduals (i.e. interlayer edges) in order to explore the functional significance of different locations to an animal’s ecology. This approach provides a novel and holistic framework incorporating in idual variability in behaviour and inter-in idual interactions. We discuss how this approach can be used in applied ecology and conservation to better assess the ecological significance of variable space use by mobile animals within a population. Further, we argue that the uptake of multilayer networks will significantly broaden our understanding of long-term ecological and evolutionary processes, particularly in the context of information or disease transfer between in iduals.
Publisher: Inter-Research Science Center
Date: 02-04-2020
DOI: 10.3354/MEPS13270
Abstract: 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 in idual variation in horizontal movement patterns, ranging from high local site fidelity ( km) for up to 3 yr, to large-scale regional movements ( km) around the entire MPA. Depth time-series data recorded vertical movement patterns consistent with other epipelagic elasmobranch species, including oscillatory ing and deep es to greater than 500 m. Though no in iduals were directly recorded departing the MPA throughout the study, the gaps in detections and estimated travel speeds documented here indicate that movement of in iduals 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.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-08-2022
Abstract: 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.
Publisher: Wiley
Date: 10-02-2021
DOI: 10.1002/ECE3.7226
Publisher: Wiley
Date: 30-05-2022
DOI: 10.1002/RSE2.286
Abstract: Coral reefs are significantly threatened by multiple environmental stressors associated with climate change. While there is growing recognition of the importance of interacting stressors on coral reefs, so far this has been primarily limited to in situ studies. Satellite remote sensing has potential for investigating coral reef exposure to multiple environmental stressors at a global scale over multiple years however, current satellite monitoring is primarily focused on thermal stress. Here we collate nine environmental variables (cloud cover, current, depth, salinity, wind, and four sea surface temperature‐based metrics) from readily available satellite datasets using the Google Earth Engine geospatial processing platform. Using ecological and health‐based thresholds obtained from the literature, we developed, using fuzzy logic (discontinuous functions), a Reef Environmental Stress Exposure Toolbox (RESET) for monitoring environmental stress exposure at multiple scales. Stress exposure scores for 3157 reefs were generated and mapped globally across 12 coral reef ecosystem regions. RESET was also applied to three case‐study reefs, previously well monitored for stress and disturbance using other methods. PCA analysis indicated that depth, current, sea surface temperature (SST) and SST anomaly accounted for the greatest contribution to the variance in environmental stress exposure in these three regions. Depth, degree heating weeks, and SST anomaly were identified as the potential drivers of inter‐ and intra‐region variation in environmental stress exposure. In idual variables were then integrated into a multi‐metric index of combined stress exposure which corroborated temporal and spatial differences due to known disturbance events. RESET provides a open access, easily interpretable set of tools and associated indices for monitoring environmental stress exposure on coral reefs, designed to inform conservation and management decisions. As such RESET has broad potential to assist in the monitoring of our increasingly imperilled coral ecosystems, in particular, those that are remote or inaccessible.
Publisher: Springer Science and Business Media LLC
Date: 09-01-2023
DOI: 10.1007/S11160-022-09751-6
Abstract: Anguillid eels are near globally distributed catadromous fishes with marine spawning areas and inshore and inland growth areas in both lotic (rivers, estuaries) and lentic (lakes, ponds, lagoons) water bodies. As predators, anguillid eels play an important ecological role in both marine and freshwater systems, and several species are harvested commercially for food. However, some of the more widely distributed species have undergone severe declines in recruitment and their population status is now of significant concern. Given the multiple and lengthy migrations undertaken by anguillid eels, understanding of the drivers of movement is fundamental for species conservation and management. Yet, despite the importance of lentic systems to their ecology, most studies on anguillid eel movement have been conducted in lotic systems. Given that key influences on eel migration in lotic water bodies, such as fluctuations in flow and water temperature, may be minimised in lentic environments, the transferability of findings between lotic and lentic systems cannot be assumed. A systematic map was constructed to synthesise current knowledge on the extrinsic and intrinsic drivers of anguillid eel movement in lentic systems. The current state of knowledge of the drivers of eel movement in lentic systems is presented and compared to the relatively well-understood drivers of movement in lotic systems. We also discuss current knowledge gaps and limitations, and identify key future research requirements to inform the management and conservation of anguillid eels in understudied lentic systems. Graphical abstract
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for David Jacoby.