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Context: Endangered pelagic thresher sharks (Alopias pelagicus) are facing high fishing pressure in many countries. As the world's largest shark fishing nation, with particularly high catch rates of thresher sharks, the impact of Indonesian fisheries has become a global priority for thresher shark conservation. Therefore, baseline data is needed to inform management and implement international agreements. Aims: This research provides data and management recommendations for data-poor targeted shark fishing in Western Indonesia, where thresher sharks are regularly caught. Methods: Daily landings data was recorded from June 2019 to December 2020 in Southwest Aceh and analysed to explore catch patterns, risk factors for thresher sharks, and potential mitigation options. Key results: Twenty-five wooden vessels of <30 gross tonnage target sharks in the Indian Ocean. We recorded a total of 109 pelagic thresher individuals during the study period, with a female-skewed sex ratio (1 female:0.39 male). Almost all pelagic threshers were caught by the bottom longline. Conclusions: Based on this data, we offer some potential management measures to reduce fisheries impacts on pelagic thresher sharks by applying a simple mitigation hierarchy framework. Implications: These results provide fisheries management recommendations, including effort limits and gear modifications. Pelagic thresher sharks are of conservation priority due to their globally endangered status. This research provides information and recommendations for data-poor fisheries in Indonesia. The results show that fishers use bottom longlines to target sharks in the eastern Indian Ocean. We offer potential management measures to reduce mortality on pelagic threshers by applying a mitigation hierarchy framework. [ABSTRACT FROM AUTHOR]

Fisheries bycatch is the greatest threat to migratory, long‐lived marine animals.Addressing bycatch ultimately requires changing fisher behaviour, yet social and behavioural sciences are rarely applied to bycatch mitigation, with an absence of theory‐informed behaviour change interventions. Moreover, mitigating bycatch is particularly challenging in small‐scale mixed‐species fisheries (SSFs), where perceptions of target and non‐target vary widely, and all catches have economic or subsistence value. Such fisheries are ubiquitous throughout the world's oceans, and bycatch mitigation in these contexts necessitates a people‐centred approach.We seek to address this gap, drawing on well‐established theories from behavioural and social sciences. We first typify bycatch as a spectrum rather than a clearly delineated component of catch, where the position of a species on this spectrum depends on fishers' beliefs regarding the outcomes of bycatch‐relevant behaviour. We then outline an approach to 'diagnose' fishers' underlying beliefs about bycatch, using the theory of planned behaviour (TPB): a widely applied and empirically tested theory for predicting and changing behaviour. Finally, we illustrate the approach using an empirical case study, exploring fishers' beliefs regarding bycatch‐relevant behaviour for three endangered elasmobranch species in a small‐scale gill net fishery in Indonesia.Our findings show how the TPB can help to understand fishers' underlying beliefs regarding bycatch, and facilitators/inhibitors of bycatch mitigation, to inform behaviour change interventions. We emphasize the need to understand the human dimensions of bycatch, especially in SSFs, where technical fixes alone will be insufficient to change behaviour. Rather, interdisciplinary approaches are needed to align fishers' needs with conservation objectives.Our bycatch spectrum and the TPB could be widely applied for disentangling drivers of bycatch in other SSFs and designing interventions which support more effective and socially just marine conservation. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Understanding wildlife markets is central to effective conservation: it can help managers and policy‐makers to predict how interventions might influence supply and demand of wildlife products, and economic welfare of wildlife users; and thus, design interventions which have better outcomes for wildlife and people. Here we apply a revealed preference method of economic valuation—hedonic price analysis (HPA)—to understand shark markets and explore the economic costs of shark conservation for small‐scale fishers. We focus on a targeted semi‐commercial shark fishery in Indonesia—which poses a threat to some shark species, but provides important economic and subsistence value for a coastal community in an impoverished region of Indonesia—and use HPA to estimate market prices and welfare measures for threatened and CITES‐listed sharks. This represents a pertinent case study with practical implications because Indonesia is the world's largest shark fishing nation, where management interventions to reduce shark fishing mortality are needed. However, such interventions will create short‐term socio‐economic trade‐offs for fishing communities, which may hamper cooperation and compliance, and raise concerns regarding the fairness and equity of conservation. Our results give significant marginal price estimates for five species of conservation and commercial importance. Dusky sharks (Carcharhinus obscurus) and bottlenose wedgefish (Rhynchobatus australiae) have the highest implicit marginal prices, at US$ 157 and US$ 144, respectively. Our estimates suggest that conservation measures, such as catch limits for endangered and CITES‐listed species, could have significant economic opportunity costs (i.e., 3.4–17.6% revenue foregone) for low‐income fishers. Innovative policy instruments are required to transform shark markets and fisheries—to effectively reduce threats to endangered species and implement CITES, whilst doing no harm to vulnerable coastal communities. Methods from econometrics can help conservation scientists to better understand wildlife markets, and make management decisions which create better outcomes for wildlife and people. [ABSTRACT FROM AUTHOR]

Manta rays (Mobula birostris and M. alfredi) are threatened by overexploitation for international trade. Indonesia was home to the world's largest documented manta fishery—Lamakera, in East Nusa Tenggara. However, in 2014, the Indonesian government declared manta rays a protected species. Here we describe an integrated intervention to reduce manta hunting and mortality in Lamakera, which combined community outreach and livelihood‐focused incentives with targeted enforcement actions; and assess its impact over a five‐year period (2013–2018) using a theory‐based research design. Results show that the intervention is associated with a significant decline in manta hunting effort and mortality (p <.001), which is correlated and temporally‐associated with conservation activities, and did not occur for modeled and natural experiment counterfactuals. Overall, total manta ray mortality declined by 86% by 2018, vs. the 2013 baseline. We conclude that a multifaceted, data‐driven approach reduced illegal hunting and trade of manta rays from 2013 to 2018. However, this impact is not indefinite; new challenges are emerging, which highlight the importance of a long‐term adaptive strategy. We make several recommendations for designing interventions to mitigate trade‐driven over‐exploitation of megafauna: (a) understand diverse drivers of human behavior; (b) adopt data‐driven problem‐oriented planning; (c) continuously document and share learning; (d) establish partnerships with diverse stakeholders to develop resilient institutions for enduring impact. [ABSTRACT FROM AUTHOR]

Sharks and their cartilaginous relatives are one of the world's most threatened species groups. The primary cause is overfishing in targeted and bycatch fisheries. Reductions in fishing mortality are needed to halt shark population declines. However, this requires complex fisheries management decisions, which often entail trade‐offs between conservation objectives and fisheries objectives. We propose the mitigation hierarchy (MH)—a step‐wise precautionary approach for minimizing the impacts of human activity on biodiversity—as a novel framework for supporting these management decisions. We outline a holistic conceptual model for risks to sharks in fisheries, which includes biophysical, operational and socioeconomic considerations. We then demonstrate how this model, in conjunction with the MH, can support risk‐based least cost shark conservation. Through providing examples from real‐world fishery management problems, we illustrate how the MH can be applied to a range of species, fisheries and contexts, and explore some of the opportunities and challenges hereto. Finally, we outline next steps for research and implementation. This is important in the context of increasing international regulation of shark fishing and trade, which must lead to reductions in shark mortality, while managing trade‐offs between conservation objectives and the socioeconomic value of fisheries. [ABSTRACT FROM AUTHOR]

Marine tourism is promoted as a substitute economic activity to unsustainable fishing, which is compatible with conservation. However, benefits of marine tourism do not typically accrue in small-scale fisheries (SSFs), which often bear the costs of conservation; they accrue to tourists and tourist-focussed businesses. We explored how marine tourism levies could operationalise the beneficiary-pays principle and address these cost-benefit inequities using an online contingent valuation (CV) survey to measure international tourists' willingness-to-pay (WTP) towards community-based shark conservation (N = 1033). Levies were widely supported (96%), with median and Turnbull mean WTP of US$ 10–14.99 and $22.02 per person per day, respectively. We combined these results with data from two marine tourism hotspots in Indonesia – Lombok and Pulau Weh – to explore the feasibility of implementing tourism levies to incentivize pro-conservation behaviour in local SSFs. Our conservative estimates indicate that marine tourism levies in Lombok and Pulau Weh could respectively generate US$ 2.3–10 million and US$ 300,000–1.3 million annually – several times greater than the estimated costs of conservation incentives in local SSFs. The marine tourism industry offers an under-utilised revenue stream for marine conservation, which could support policy aspirations such as ' a sustainable and equitable blue economy '. [ABSTRACT FROM AUTHOR]

Many shark and ray species (Class Chondrichthyes, herein 'sharks') are threatened by overfishing. Tackling this requires implementation of context-specific fisheries management measures, which are both technically effective and socio-economically feasible. Here we explore the cost-effectiveness of various input-oriented management measures for mitigating capture of seven priority shark taxa (i.e., threatened and CITES-listed species) in a small-scale longline mixed-species shark fishery in Indonesia, where there is a need to balance difficult trade-offs between conservation and socio-economic objectives. We apply Boosted Regression Trees (BRT) to analyse five years of landings and profit data, to identify and assess the relative influence of different plausible management measures (e.g., effort restrictions, gear restrictions, spatio-temporal closures). We then use predictive models to inform a semi-quantitative assessment of the hypothetical cost-effectiveness of these management measures, based on the estimated conservation benefits (reduced risk of capture of priority taxa) and socio-economic cost (relative profit foregone). Our results show that fishery closures in January–March, depth limits at <100 m, hook limits at <500 hooks, and gear restrictions on bottom longlines could have the greatest relative conservation impact for lowest profit foregone. However, there are clear trade-offs between taxa, with these measures primarily benefiting Critically Endangered bottlenose wedgefish (Rhynchobatus Australiae) and scalloped hammerheads (Sphyrna lewini), while potentially increasing pressure on Vulnerable silky sharks (Carcharhinus falciformis) and Endangered mako sharks (Isurus spp.). When shark fishing is important for economic welfare, and entire fishery closures or buy-outs are unfeasible, managing small-scale shark fisheries for multiple outcomes may require hard choices. This may require prioritising slow-growing Critically Endangered taxa for protection – by restricting fishing during seasons and at depths in which they are most susceptible to capture – while faster-growing taxa can continue to provide benefits for coastal communities. [ABSTRACT FROM AUTHOR]

Sharks and their cartilaginous relatives (Class Chondrichthyes, herein 'sharks') are one of the world's most threatened species groups. Their slow life history traits and vulnerability to capture make them particularly susceptible to overfishing, and they are widely caught in both target and by-catch fisheries. Fisheries management measures that can effectively reduce shark fishing mortality are urgently required to halt population declines and species extinctions. We provide an overview of typical measures for understanding and managing risks to sharks, and highlight critical gaps relating to incorporating socio-economic factors in to research and management. We argue that neglecting these factors hinders effective shark conservation, and has negative consequences for people. We emphasise the importance of a holistic approach, which explicitly considers socio-economic factors in decision-making. Based on this, we propose the first framework for assessing feasibility in a shark management context, which could be integrated with traditional fisheries risk assessments in order to bridge this gap. This framework considers key dimensions of the costs, benefits and overall enabling environment for shark management in a given fishery. Overall, managers and policy makers must consider socio-economic factors in shark conservation efforts to deliver better outcomes for sharks and people. Our simple feasibility framework can support this by enabling costs, benefits and context to be explicitly considered in planning and policy-making, alongside the typical biological and technical risks to sharks in fisheries. • An overview of typical measures for managing risks to sharks is given. • Gaps relating to socio-economic aspects of management are highlighted. • Socio-economic complexities of managing shark fisheries are described. • Priorities for including socio-economic factors in decision-making are discussed. • A framework to assess feasibility in shark management planning is proposed. [ABSTRACT FROM AUTHOR]