Output list
Journal article
Critical habitats for sharks and rays in Asia remain largely unprotected
Published 2026
Biodiversity and Conservation, 35, 7, 1 - 38
The Asia region harbors exceptional chondrichthyan (shark, ray, and chimaera) diversity but faces intense fishing pressure. The Important Shark and Ray Area (ISRA) process provides a collaborative, evidence-based framework to identify critical habitats and inform spatial management. We assessed ISRAs across the Bay of Bengal, Southeast Asia, and the Northwest Pacific to characterize their extent, ecological significance, and conservation relevance. We delineated 122 ISRAs spanning ~ 1 million km2 (~ 3% of the region) across 12 jurisdictions and international waters, encompassing habitats for 121 species (~ 30% of Asia’s chondrichthyans), 76% of which are threatened. Depleted taxa (e.g., giant guitarfishes, Glaucostegidae) were represented, but charismatic megafauna (e.g., Whale Shark Rhincodon typus) were overrepresented. In contrast, deepwater and freshwater species were underrepresented. Reproductive Areas were the most common ISRA sub-criterion applied (52% of ISRAs), largely in nearshore zones, while areas for range-restricted species were less frequently (18%) identified. Twelve ISRAs overlapped with biodiversity hotspots, including seven in areas of high overall chondrichthyan species richness and five in areas of high range-restricted species richness. Citizen science was the predominant research method used to delineate ISRAs, while fisheries data were underused despite the region’s major fisheries footprint. Geographic coverage was uneven: Indonesia held the most ISRAs (n = 40; 71.7% of ISRA coverage) while eight jurisdictions (e.g., Viet Nam, China, Republic of Korea) lacked ISRAs due to data gaps. Protection shortfalls are stark: MPAs cover < 5% of national waters in 16 jurisdictions (eight with < 1%); 5.4% of ISRA area lies within MPAs; and only 2.8% of ISRA spatial extent overlaps with no-take zones. These results provide a regional foundation to guide spatial planning, prioritize management, close data gaps, and support recovery of Asia’s diverse and imperiled chondrichthyan assemblages.
Journal article
Valuing conservation and natural wealth: The blue economy of manta ray watching in the Maldives
Published 2026
PLoS One, 21, 6, 1 - 28
Amid declining manta ray populations globally, the well-established and growing manta ray tourism industries generate substantial economic benefits and aid protective legislation for these threatened elasmobranchs. As flagship species, manta rays are a drawcard for marine wildlife tourism and a gateway for engaging the public and communities in conservation. Healthy marine ecosystems are the key drivers of employment and economic sustainability for island nations such as the Maldives. However, there are many stakeholders competing for these shared resources, which can result in environmental degradation. Economic valuations are a powerful tool for justifying the conservation efforts of threatened species and natural areas, especially in light of competing stakeholders. Using tour operator surveys (n = 106) and data mining, this study provides an updated assessment of manta ray watching tourism in the Maldives and represents the first national valuation of its direct economic and socio-economic benefits. In 2021, manta ray tourism in the Maldives generated an estimated US$227.3 million, including US$39 million on manta ray focused diving and snorkelling excursions, and US$188.3 million in related tourist expenditure, representing 2.6% of the national Gross Domestic Product. This industry appears to have grown around 380% since 2008 (US$8.1 million) and manta ray watching is now offered by 80% of tourism operators nation-wide. Our findings revealed that manta rays hold intrinsic value and cultural significance within local communities. Acknowledging this, the flow-on benefits to the community extend beyond this industry, reaching local businesses, employed staff, and the government with the direct economic benefits of the manta ray tourism industry are estimated at over US$311 million per year. Such value highlights the significance of manta rays for the Maldives and the need for effective management centred on manta ray conservation to safeguard future prosperity and mitigate the potential impact of tourism on manta ray populations.
Book
A Field Guide to the Vertebrates of Lady Elliot Island, Great Barrier Reef
Published 2026
A Field Guide to the Vertebrates of Lady Elliot Island was created to capture a living snapshot of life on and around this remarkable coral cay. As ocean temperatures shift and species move into new areas, understanding what’s here now is the first step in tracking change. This guide provides that essential benchmark.
Developed through the Leaf to Reef research project, the book brings together years of scientific surveys alongside invaluable sightings from resort staff and passionate citizen scientists. The result? New records for Australian waters, documented range extensions, and even species new to science.
Inside, you’ll find vibrant full-colour photographs and accessible species profiles covering birds, sharks, rays, fishes, mammals, and reptiles. Special “creature features” spotlight some of Lady Elliot Island’s most iconic wildlife, including red-tailed tropicbirds, reef manta rays, Lady Elliot shrimpgobies, humpback whales, and green sea turtles.
More than a field guide, this book is a celebration of collaboration, discovery, and the extraordinary biodiversity of the southern Great Barrier Reef — a vital resource for anyone who wants to explore and understand this changing marine world.
Journal article
Published 2026
Journal of Plankton Research, 48, 3, 1 - 8
Zooplankton are vital links in marine food webs, yet their biomass remains challenging to quantify across broad spatial and temporal scales. This study introduces the Zooplankton Visual Index–a simple, rapid and scalable semi-quantitative method for evaluating zooplankton biomass through underwater observations. Following the establishment of a standardized protocol, validation against in situ net samples demonstrated that index levels increased consistently with measured biomass and predictable shifts in community composition. We then applied the validated index to a 9-year dataset of reef manta ray (Mobula alfredi) sightings in the Maldives. Increased M. alfredi abundance significantly correlated with higher index levels, confirming that the index effectively captures the food environment as an important predictor of behavior and habitat use. Thus, the Zooplankton Visual Index provides an accessible and validated tool for assessing prey availability, enabling researchers, non-specialist field staff and citizen science programs to contribute to broad-scale ecological research and conservation efforts for marine megaplanktivores.
Journal article
Published 2026
Ecology and Evolution, 16, 1, 1 - 22
The Western Indian Ocean (WIO) is known for its high diversity of chondrichthyans (sharks, rays, and chimaeras). However, intense fishing pressure has led to severe population declines and local extinctions of several species. The Important Shark and Ray Area (ISRA) process is a collaborative, evidence-based approach used to identify critical habitat for chondrichthyans. We analysed ISRAs across the WIO to quantify the diversity of research methods used to identify them, evaluate spatial overlap with designated marine protected areas (MPAs), model the influence of several species- and jurisdiction-specific variables on ISRA delineation, and explore the importance of incorporating unpublished data into the delineation process. In total, 125 ISRAs (covering > 2.8 million km2; ~10% of total regional surface area) were identified within the WIO from surface waters to ~2000 m depth. These ISRAs contain over one-third (n = 104, 39%) of the 270 chondrichthyan species reported from the region, with 76% being threatened with extinction according to the IUCN Red List of Threatened Species. The underlying evidence supporting ISRA identification was primarily drawn from relatively inexpensive research methods, such as visual census (25%) or fish-market/landing site surveys (22.6%), as well as citizen science (9.5%). Incorporating unpublished records substantially increased the frequency of ISRA delineation, leading to expanded taxonomic and geographic coverage. Still, the full dataset was influenced by the same biases as the published record, tending to favour large-bodied, wide-ranging, and shallow-dwelling species. Only 7.1% of ISRAs are within designated MPAs, with just 1.2% in fully protected no-take areas. The highest no-take overlap occurs in the Seychelles and Chagos Archipelago. These findings highlight the shortfalls in spatial protection of chondrichthyan habitats, but also present a strategic opportunity for policy-makers and resource managers to improve current MPA coverage and meet their commitments under international agreements, such as the Global Biodiversity Framework.
Journal article
A review of manta and devil ray courtship and mating
Published 2026
Environmental Biology of Fishes, 109, 1 - 21
The family Mobulidae (genus Mobula), comprising manta and devil rays, represents a wide-ranging, threatened group of species. The courtship and mating behaviours of most mobulid species remain poorly understood, with the majority of the existing literature focusing on the reef manta ray (M. alfredi). For this study, new observations were compiled globally via Internet and YouTube searches as well as through engagement with the scientific community, with particular focus on the lesser-studied species. Each video or photographic observation was analysed and categorised based on known courtship stages. Here, we present 87 new records of courtship/mating behaviour from eight of the ten described mobulid species across 18 countries/territories. All seven stages were recorded in the study: Initiation (n = 17), Endurance (n = 71), Evasion (n = 52), Pre-copulation positioning (n = 21), Copulation (n = 9), Post-copulation holding (n = 2), and Separation (n = 6). The videos and photographs presented for the Atlantic pygmy devil ray (M. hypostoma) represent a first for this species, while the absence of any courtship or mating observations for the longhorned pygmy devil ray (M. eregoodoo) and the lack of new observations for the bentfin devil ray (M. thurstoni) demonstrate that further investigation is needed for the lesser-studied species. New records were compared to the existing literature and novel behaviours, such as male-to-male pseudo-courtship (documented in four species), were described. Our results substantially expand the body of knowledge on mobulid courtship and mating behaviours. These observations align with the previously described sequential framework, with additional refinements for individual species and novel delineations of species-specific behaviours within the defined stages.
Journal article
Published 2026
Biological Conservation, 313, 1 - 21
Significant progress has been made in advancing priority actions to conserve manta and devil rays, yet implementation and enforcement of protective measures often fall short, leaving most mobulid populations at risk of overfishing. Drawing on a literature review, fisheries databases, agency reports, and expert interviews, we assess global trends in mobulid catch and mortality. We examine both targeted and incidental catch, in small (<15 m, ‘SV’) and large (>15 m, ‘LV’) vessel fisheries to identify hotspots with the highest risk of fisheries-related mortality and population decline. We estimate global fisheries catch at 264,520 (184,407–344,987) mobulids per year, with SV fisheries accounting for 87 % of global mortality. The highest-risk hotspots, based on mortality and declines, are located in India, Indonesia, Sri Lanka, Peru, and Myanmar. Mobulid retention is driven by demand, with higher mortality rates observed in countries exporting gill plates, and to a lesser extent, in those trading meat domestically or internationally. We recommend urgent implementation and enforcement of mobulid listings under the Convention on International Trade in Endangered Wild Flora and Fauna (CITES), the Convention on the Conservation of Migratory Species of Wild Animals (CMS), and national protective measures, including (i) uplisting mobulids to CITES Appendix I, (ii) full legislative protection for all mobulid species in high-risk fishing nations to reduce demand, (iii) avoiding fishing in critical habitats through permanent or temporary targeted area closures, or management, (iv) limiting drift gillnet effort, and (v) involving fishers in management decisions and implementation.
Journal article
Published 2026
Marine Mammal Science, 42, 1, 1 - 15
Monitoring cetaceans in Australia's Great Barrier Reef (GBR) is essential for understanding their ecological roles and informing conservation, yet traditional visual surveys are limited by logistical constraints. Passive acoustic monitoring (PAM) offers a complementary solution, particularly in acoustically complex coral‐reef habitats of the southern GBR. Over 2 years, we deployed an autonomous recorder at Lady Elliot Island to document cetacean presence and assess environmental associations. We detected vocalizations from humpback whales ( Megaptera novaeangliae ), dwarf minke whales ( Balaenoptera acutorostrata subsp.), and delphinids, likely spinner ( Stenella longirostris ) and/or bottlenose dolphins ( Tursiops spp.). Humpback whale song dominated recordings from June through October, while dwarf minke whale “Star‐Wars” calls occurred from May to August, marking the first acoustic evidence of this subspecies within the southern GBR. Dwarf minke whale detections correlated positively with chlorophyll‐ a concentration, whereas humpback whale detections were negatively associated with wind speed. Rorqual vocalizations declined during periods of elevated anthropogenic noise, while odontocete detections remained unaffected. These results highlight PAM's effectiveness for detecting cetaceans within complex reef soundscapes and suggest acoustic niche partitioning among taxa. These critical baseline data inform management strategies for understudied GBR cetacean populations and establish a robust framework for future long‐term monitoring efforts and effective conservation actions.
Journal article
Important Shark and Ray Areas can inform conservation planning in the Mediterranean and Black Seas
Published 2025
iScience, 28, 8, 1 - 21
The designation of protected areas needs to accelerate rapidly to achieve Target 3 of the Global Biodiversity Framework (GBF), raising concerns that protected area quality will be overlooked. Rather than basing systematic conservation planning primarily on species ranges, critical habitats for life history functions should be prioritized to enhance conservation outcomes. Such critical habitats are being identified as “Important Areas,” including Important Shark and Ray Areas (ISRA) for chondrichthyans. Solutions from systematic conservation planning scenarios with 73 chondrichthyan species in the Mediterranean and Black Seas greatly differed between approaches that ignore or include ISRAs. Including ISRAs led to higher costs for fisheries but protected a similar surface area (∼27% in both scenarios), while achieving better conservation outcomes. We highlight ways of reducing fishing costs while maintaining ISRA-based solutions. Systematic conservation planning using Important Areas gives decision makers a tool to balance cost with improved conservation quality, ultimately enhancing protected area network effectiveness by prioritizing critical habitats.
Journal article
Published 2025
Reviews in Fish Biology and Fisheries, 35, 117 - 144
Skates and rays (Batoidea) play a significant ecological role, contributing to ecosystem services through bioturbation and acting as vital intermediate components of the trophic chain in various aquatic environments. Despite their wide global distribution and ecological importance, batoids receive less attention than their shark relatives, resulting in substantial knowledge gaps that might impede a comprehensive understanding of their conservation status. This review addresses critical aspects of their capture, handling, tagging, and release to provide readers with crucial information needed to perform research on batoids. Protocols for analgesia, anaesthesia, and euthanasia are also discussed, taking into account the ethical and logistical considerations necessary for research involving this group of species. This information can give researchers and ethics committees the knowledge to conduct and approve studies involving batoids, thereby promoting more effective and ethical research practices.