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Unifying models have shown that the amount of space used by animals (e.g., activity space, home range) scales allometrically with body mass for terrestrial taxa; however, such relationships are far less clear for marine species. We compiled movement data from 1,596 individuals across 79 taxa collected using a continental passive acoustic telemetry network of acoustic receivers to assess allometric scaling of activity space. We found that ectothermic marine taxa do exhibit allometric scaling for activity space, with an overall scaling exponent of 0.64. However, body mass alone explained only 35% of the variation, with the remaining variation best explained by trophic position for teleosts and latitude for sharks, rays, and marine reptiles. Taxon-specific allometric relationships highlighted weaker scaling exponents among teleost fish species (0.07) than sharks (0.96), rays (0.55), and marine reptiles (0.57). The allometric scaling relationship and scaling exponents for the marine taxonomic groups examined were lower than those reported from studies that had collated both marine and terrestrial species data derived using various tracking methods. We propose that these disparities arise because previous work integrated summarized data across many studies that used differing methods for collecting and quantifying activity space, introducing considerable uncertainty into slope estimates. Our findings highlight the benefit of using large-scale, coordinated animal biotelemetry networks to address cross-taxa evolutionary and ecological questions.

Symbiotic relationships between fishes and other organisms are not always easily defined, and three-way symbiotic relationships are rarely reported. Here we examine the relationship between the endangered whale shark, echeneids (remoras and sharksuckers) and a symbiotic copepod. Through their symbiosis with whale sharks, sharksuckers gain one food source from the host’s parasites and energetically-free transportation to foraging areas, where they are also able to feed on the prey targeted by their hosts. The relationship between whale sharks and sharksuckers is complex, and most accurately described as mutualism. Likewise, the whale shark and copepod relationship is also complex, and could be described as a parasitic relationship with commensal or even mutualistic characteristics. Although echeneids are not considered to form host-specific relationships and can be free-ranging, the whale shark copepod occurs only on whale sharks; its survival inextricably linked to that of its host.

Marine traffic is increasing globally yet collisions with endangered megafauna such as whales, sea turtles, and planktivorous sharks go largely undetected or unreported. Collisions leading to mortality can have population-level consequences for endangered species. Hence, identifying simultaneous space use of megafauna and shipping throughout ranges may reveal as-yet-unknown spatial targets requiring conservation. However, global studies tracking megafauna and shipping occurrences are lacking. Here we combine satellite-tracked movements of the whale shark, Rhincodon typus, and vessel activity to show that 92% of sharks’ horizontal space use and nearly 50% of vertical space use overlap with persistent large vessel (>300 gross tons) traffic. Collision-risk estimates correlated with reported whale shark mortality from ship strikes, indicating higher mortality in areas with greatest overlap. Hotspots of potential collision risk were evident in all major oceans, predominantly from overlap with cargo and tanker vessels, and were concentrated in gulf regions, where dense traffic co-occurred with seasonal shark movements. Nearly a third of whale shark hotspots overlapped with the highest collision-risk areas, with the last known locations of tracked sharks coinciding with busier shipping routes more often than expected. Depth-recording tags provided evidence for sinking, likely dead, whale sharks, suggesting substantial “cryptic” lethal ship strikes are possible, which could explain why whale shark population declines continue despite international protection and low fishing-induced mortality. Mitigation measures to reduce ship-strike risk should be considered to conserve this species and other ocean giants that are likely experiencing similar impacts from growing global vessel traffic., [Significance] Global vessel traffic is increasing alongside world economic growth. The potential for rising lethal ship strikes on endangered species of marine megafauna, such as the plankton-feeding whale shark, remains poorly understood since areas of highest overlap are seldom determined across an entire species range. Here we show how satellite tracking whale sharks and large vessel movements globally provides a means to localize high-overlap areas and to determine how collision risk changes in time. Our results point to potential high levels of undetected or unreported ship strikes, which may explain why whale shark populations continue to decline despite protection and low fishing-induced mortality. Collision mitigations in high-collision-risk areas appear necessary to help conserve this iconic species., Funding for data analysis was provided by the UK Natural Environment Research Council (NERC) through a University of Southampton INSPIRE DTP PhD Studentship to F.C.W. Additional funding for data analysis was provided by NERC Discovery Science (NE/R00997/X/1) and the European Research Council (ERC-AdG-2019 883583 OCEAN DEOXYFISH) to D.W.S., Fundação para a Ciência e a Tecnologia (FCT) under PTDC/BIA/28855/2017 and COMPETE POCI-01–0145-FEDER-028855, and MARINFO–NORTE-01–0145-FEDER-000031 (funded by Norte Portugal Regional Operational Program [NORTE2020] under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund–ERDF) to N.Q. FCT also supported N.Q. (CEECIND/02857/2018) and M.V. (PTDC/BIA-COM/28855/2017). D.W.S. was supported by a Marine Biological Association Senior Research Fellowship.

A new microbothriid monogenean

The whale shark is an ideal flagship species for citizen science projects because of its charismatic nature, its size, and the associated ecotourism ventures focusing on the species at numerous coastal aggregation sites. An online database of whale shark encounters, identifying individuals on the basis of their unique skin patterning, captured almost 30,000 whale shark encounter reports from 1992 to 2014, with more than 6000 individuals identified from 54 countries. During this time, the number of known whale shark aggregation sites (hotspots) increased from 13 to 20. Examination of photo-identification data at a global scale revealed a skewed sex-ratio bias toward males (overall, more than 66%) and high site fidelity among individuals, with limited movements of sharks between neighboring countries but no records confirming large, ocean basin-scale migrations. Citizen science has been vital in amassing large spatial and temporal data sets to elucidate key aspects of whale shark life history and demographics and will continue to provide substantial long-term value.

Aim Understanding the spatial and temporal variation in the distribution of migratory species is critical for management and conservation efforts. However, challenges in observing mobile marine species throughout their migratory pathways can impede the identification of critical habitat, linkages between these habitats and threat-mitigation strategies. This study aimed to gain insight into the long-term residency and movement patterns of the whale shark (Rhincodon typus) and to reveal important habitat in the context of R. typus usage of existing Marine Protected Areas (MPAs). Location South-eastern Indian Ocean. Methods Satellite telemetry was used to remotely track the long-term movements of 29 R. typus, and to quantify shark usage of the existing MPA network. From the tracking data and environmental predictors, nonlinear models were developed to predict suitable R. typus habitat throughout the south-eastern Indian Ocean. Results This study includes the first documented complete return migrations by R. typus to Ningaloo Marine Park, which was found to be an important area for R. typus all year-round. We found that while existing MPAs along Australia's west coast do afford some protection to R. typus, telemetry-based habitat models revealed large areas of suitable habitat not currently protected, particularly along the Western Australian coast, in the Timor Sea, and in Indonesian and international waters. Main conclusions Animal-borne telemetric devices allowed the gathering of long-term spatial information from the elusive and highly mobile R. typus, revealing the spatial scale of their migration in the south-eastern Indian Ocean. Suitable habitat was predicted to occur inside conservation areas, but our findings indicate that the current MPA network may not sufficiently protect R. typus throughout the year. We suggest that telemetry-based habitat models can be an important tool to inform conservation planning and spatial management efforts for migratory species.

Background Whale sharks (Rhincodon typus) are generally sighted during daytime. In the southern atolls of Maldives they are instead sighted primarily at night inside the atoll. Tuna fishermen attract baitfish with a strong halogen lamp, creating substantial plankton concentrations. Whale sharks opportunistically feed near the surface under fishing boats anchored in a 40 m deep lagoon, often disturbing bait collection. This unique occurrence is well known locally but not internationally and it has yet to be the focus of a targeted research program, due in part to the remoteness of the area. This study aims to provide preliminary answers for the following question: Are whale sharks simply moving through Thaa Atoll or do they remain inside for an extended period? Approach Two sharks were tagged in December 2015, while feeding at night under the light of fishing boats inside Thaa Atoll. Wildlife Computers SPOT 5 satellite tags, secured via non-invasive fin clamps, were deployed on the first dorsal fin of two sharks to monitor their geographic movements. This pilot tagging project was undertaken in conjunction with a photo identification study (using Wildbook for Whale Sharks), to compare to other photo ID data collected during other sighting events before and after tagging. Results The first shark (M-109) retained the tag for a period of 25 days, and appeared to remain inside the atoll during this period. Frequent movements within the atoll were recorded, up to 20 km over a 24 h period. M-109 was regularly recorded at the northeast area within the atoll, near a consistent baitfish collection ground where this individual was originally tagged. However, on occasion, M-109 was recorded far from bait collection areas and/or during rough nights with no fishing activity, suggesting natural surface feeding behavior. Despite no data forthcoming from the second tagged shark (likely because of tag dislodgement through interaction with fishers nets), this individual was resighted (confirmed through photo-identification) feeding under fishing nets, at a similar location to the first sighting, 22 days later. Conclusions 1) Satellite data, for M-109, and photo-identification data, for the second shark, confirmed both sharks inside the atoll over a 25 and 22 day period respectively, leading to the possibility of an extended stay throughout the Maldivian dry season. 2) Tagged whale shark M-109 was confirmed via satellite uplinks inside Thaa Atoll on 24 of 25 days for which we have data, suggesting it did not leave the atoll during the 25 day monitoring period. M-109 showed extensive movement within the atoll, far from bait collection areas, suggesting that local fisheries may not be the only source of food exploited by whale sharks. While the results are preliminary, the next phase of research in this potential seasonal whale shark sanctuary will focus on: establishing the frequency of fisher/shark interactions within Thaa Atoll; productivity/plankton studies inside the atoll; an increased number of whale sharks satellite-tagged; expansion of photo-identification work. This study represents the first whale shark tagging study officially recognized and permitted by the Maldivian government and it was performed under governmental supervision. It represents a milestone for the future of whale shark tracking research in the country.

Background Prior to 1999, the conservation status of the biggest fish in the sea was listed by the World Conservation Union (IUCN) as ‘Indeterminate – Data Deficient’ in its Red List of Threatened Species publication. A Species Report was commissioned in 1999 and the Whale Shark's status was subsequently upgraded to ‘Vulnerable’ in 2000. Much attention has been afforded this species since 2000, with various protective measures implemented at the local, national and international scale. But has it had any effect? Approach Literature Review and discussions with stakeholders from across the globe was used to investigate the current state of play. A recent updated IUCN Red List Report was also consulted. Areas of concern are highlighted and suggested ways forward discussed. Results Whale Sharks are listed under many international conventions e.g. the United Nations Convention on the Law of the Sea (UNCLOS); the Bonn Convention for the Conservation of Migratory Species of Wild Animals (CMS); the Convention on International Trade in Endangered Species (CITES). There is however little evidence of actions under these Conventions. The Whale Shark is known to occur in the waters of more than 100 countries – yet it receives protection in less than 50% of these. One country that lists protection for this species is China – the location of the largest active commercial whale shark fishery. Yet enforcement of existing laws is lacking. A review of the conservation status for the Whale Shark was undertaken in 2015 resulting in no change to its ‘Vulnerable’ assessment in the IUCN's 2016 Red List. The main threats are fisheries catches, bycatch in nets, vessel strikes, whale shark tourism, marine pollution, and the inability for implementation/actions under current laws and Conventions. Conclusions Where are we failing – and what needs to be done? For a start, we need better information, starting with regional and global population assessments to establish population trends globally (at present ‘unknown’ in the latest Red List Assessment). We need improved monitoring of threats and the means to implement adjustments as required (including tourism activities) to minimise impacts. We must have an increased level of data sharing: greater collaboration between researchers, especially to maximise the use of limited available resources to achieve tangible outcomes (which can then be reviewed by relevant authorities when implementing conservation measures). And then an increased level of public education on a local, national and global scale – to help minimise threats (esp. fin trade/habitat destruction e.g. various marine industries; development etc.). Perhaps consumer-driven pressure to make it unviable for stocking/sourcing of whale shark products? And then could it be possible to have a fisheries quota – and benefit the global conservation of this species? Discussions need to be had.

Background Through travel, people discover whale sharks. They also come to know about the problem of the animals safety. Different things may be more or less strong at hurting or helping the sharks. Tourism may move other things that hurt sharks more than tourism away. Not all tourism is the same. Some tourism hurts sharks more. Not all places with sharks are the same. Some places are safer. A tourism service directory map gathers some services that help travellers. It shows different services for different things that different people may want to do. It can gather only the best services. It can show people the best services for their money and other needs. Good tourism helps sharks most where it is least safe for them. A service directory may show those services because they help the least safe sharks. If no services are where sharks are not safe, the directory can help make new services by sending travellers or giving help. If a bad thing happens to the people who give services at a place then the directory may help by sending more people to those services or giving help. People who run the directory must choose which services are good or in need. They must choose which places are safe and not safe for whale sharks. They must choose what services to show other people. Approach We look at two approaches that explain helping the whale shark with a tourism service directory. The first approach is ‘citizen participation’. All people who use the directory are its citizens. They participate by: Letting it help them chose servicesLearning about the whale shark and how services hurt or help themKnowing about this when they decide which services to useGathering information about the whale shark and the things that hurt or help them when they use services,Asking other people to join the service directoryDeciding which services the directory should help create to help the whale sharkDeciding which services the directory should help when bad things hurt the people who make the servicesDeciding which tourism services are not good and should not be in the directory. The second approach is ‘distributive justice’. If citizens of the service directory decide where money and tourists go then they must serve the shark and people who serve it the same as each other. To do this the citizens decide on the control of the directory with three stages: A larger law that all other controls must follow. This helps stop the controls going too far and hurting people who serve the whale shark. It is the constitution and design stage.Laws of how the service directory is controlled. Where tourists and money should be put. People who create these laws should work for the good of the worst off sharks and people and not their own reasons. This is the legislation and development stage.People who decide on whether each service should be in the directory, whether it should be created or helped. They should act as though they are the law and are answerable to the laws of the directory. This is the enacting stage. Results People who use the whale shark tourism directory should be citizens of the service directory. As they participate with the directory they do more for the whale shark. They must also be just towards the shark and the people who serve it. Conclusions Tourism service directory maps can be used for more than advertising. They can direct the tourism industry to help the whale shark.

Background Gathering data on the life of enigmatic animals remains a challenge, despite its important role in biodiversity conservation and management. For many species, biogeographic investigations are largely the result of information that is generated from multiple sources, often over long time-scales, because measuring biogeographic and biological data over large geographic areas is simply not feasible by a single team of researchers. But in the current age of a well-educated public and accessible and mobile digital technology, scientists are now able to harness the observations of many, thus infinitely increasing their power of observation. Despite its status as the world's largest fish, there remains a paucity of information on the biology and ecology of whale sharks (Rhincodon typus). This species is however a prime target for ‘citizen science’ monitoring because of its charismatic nature, presence at many coastal aggregation sites and the growth of ecotourism around this species. Approach Information on whale shark sightings worldwide can be gathered by various stakeholders and stored in the Wildbook for Whale Sharks (www.whaleshark.org) database. Whale shark identification images are collected when a swimmer photographs the individual's unique spot pattern immediately behind the gill slits, which is distinct and long-lasting, and this image (with associated sighting data and information on shark size and sex) is then submitted to the online database. Computer-assisted scanning technology is then employed to determine whether the individual whale shark in question is a ‘new’ shark or a ‘resight’ of a previously reported whale shark within the database. Wildbook can then be queried to gain insights on various aspects of whale shark biology and ecology from data available at the various global hotspots. Results Members of the public and researchers alike contributed in this collaborative citizen science project enabling (as of 31 December 2014) almost 30000 whale shark encounter reports, comprising 6300+ individuals from 54 countries, to be identified. The number of recognized global aggregation sites (constellations) has increased from 13 to 20. The majority of these (14 out of 20) show a marked sex-ratio bias towards males (>66%). Site fidelity is relatively high, with an overall mean percentage of sharks returning to the 20 hotspots in two or more years of 35.7% (to a maximum of 21 years). Despite photo-identification revealing movements of sharks between a number of neighbouring countries/regions, there are no records confirming large, ocean basin-scale migrations. Strong seasonality in sightings is evident at many locations, suggesting that in general, that these aggregations are frequently exploiting known coastal feeding opportunities. Conclusions This study demonstrates the utility of citizen science in amassing large datasets and their utility in elucidating key aspects of whale shark life-history and demographics.

Whale sharks (Rhincodon typus) seasonally aggregate at Western Australia’s Ningaloo Reef in the austral autumn and winter, but their occurrence beyond this region during spring and summer remains elusive. The aggregation at Ningaloo Reef coincides with a pulse of productivity following mass coral spawning in early autumn, with the population during this period dominated by juveniles that amass for feeding purposes. To investigate their movement patterns beyond Ningaloo Reef, whale sharks were fitted with SPOT (n = 13) or SPLASH (n = 1) tags between April and September (2010–14). Tagged whale sharks ranged in total length from 3 to 9 m. Each whale shark was also photographed for its subsequent identification using Wildbook for Whale Sharks, and their years of residency at Ningaloo Reef determined. Temporal and spatial observations of whale shark sightings were also determined through the conducting of interviews with people throughout 14 coastal towns along the Western Australian coastline, as well as through historical sightings and the Wildbook database. Satellite tracking revealed that all sharks remained relatively close to the Western Australian coast, travelling a mean minimum distance of 1667 (±316, s.e.) km. Public reports, coupled with satellite tracking, demonstrated that whale sharks inhabit most of the Western Australian coast (from 35°S to 12°S), and that seasonal migrations beyond Ningaloo Reef may be to the north or south and may similarly be associated with areas of increased productivity.