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Aim: Biogeographic boundaries and genetic structuring have important effects on the inferences and interpretation of effective population size (Ne) temporal variations, a key genetics parameter. We reconstructed the historical demography and divergence history of a vulnerable coastal high‐trophic shark using population genomics and assessed our ability to detect recent bottleneck events. Location: Western and Central Indo‐Pacific (IPA), Western Tropical Atlantic (WTA) and Eastern Tropical Pacific (EPA). Taxon: Carcharhinus leucas (Müller & Henle, 1839). Methods: A DArTcap™ approach was used to sequence 475 samples and assess global genetic structuring. Three demographic models were tested on each population, using an ABC‐RF framework coupled with coalescent simulations, to investigate within‐cluster structure. Divergence times between clusters were computed, testing multiple scenarios, with fastsimcoal. Ne temporal variations were reconstructed with STAIRWAYPLOT. Coalescent simulations were performed to determine the detectability of recent bottleneck under the estimated historical trend for datasets of this size. Results: Three genetic clusters corresponding to the IPA, WTA and EPA regions were identified, agreeing with previous studies. The IPA presented the highest genetic diversity and was consistently identified as the oldest. No significant within‐cluster structuring was detected. Ne increased globally, with an earlier onset in the IPA, during the last glacial period. Coalescent simulations showed that weak and recent bottlenecks could not be detected with our dataset, while old and/or strong bottlenecks would erase the observed ancestral expansion. Main Conclusions: This study further confirms the role of marine biogeographic breaks in shaping the genetic history of large mobile marine predators. Ne historical increases in Ne are potentially linked to extended coastal habitat availability. The limited within‐cluster population structuring suggests that Ne can be monitored over ocean basins. Due to insufficient amount of available genetic data, it cannot be concluded whether overfishing is impacting Bull Shark genetic diversity, calling for whole‐genome sequencing. [ABSTRACT FROM AUTHOR]

The bull shark (Carcharhinus leucas) is an apex predator with a wide distribution in tropical and warm temperate waters. This species is known to utilise freshwater systems and estuaries as nursery grounds. During a wider bull shark tagging survey in the Rewa River, Fiji, in 2017 and 2018, 27 neonate bull sharks with red eye pupils were recorded. This opportunistic observation prompted an examination of water quality parameters in the Rewa River to collect preliminary data on the potential cause of pollution. Water samples were analysed for faecal indicator bacteria (Escherichia coli), ammonia, total nitrogen, and various metals. Results indicated high levels of E. coli contamination, as well as elevated ammonia and total nitrogen concentrations. However, due to the limited sample size and the likelihood of additional underlying causes, a definitive causal relationship could not be established. Hence, this finding stands as an opportunistic observation, detailed here for documentation and stimulation of discourse. Field observations of 27 neonate bull sharks with red eyes in the Rewa River, Fiji, raised concerns about water quality. Analysis indicated high levels of Escherichia coli contamination, ammonia, and total nitrogen. However, the definitive causal relationship is yet to be investigated. [ABSTRACT FROM AUTHOR]

Wildlife tourism uses various stimuli to attract species and facilitate close encounters. Such activities are often referred to as provisioning, however the term is used interchangeably, and sometimes erroneously, with attracting, feeding, luring, and chumming, all of which lack consistent definitions. Here, we review the current use of provisioning-associated terminology in marine bird, teleost (bony fish), marine mammal, marine reptile, ray and shark tourism, within the scientific literature and on tourism operator webpages. We then propose to reclassify provisioning into Feeding, Attracting, and Modifying habitat, providing eight specific terms that reflect: (1) if the stimulus exploits wildlife appetite or search for preferred habitat; (2) the nature of the attractant (consumable or not); (3) the intention of the activity if using consumable attractants (direct, indirect, or incidental feeding) or modified habitat (intentional or repurposed modification); and (4) which species are affected by the activity (target or non-target species). We applied these terms to wildlife tourism around the world to gain better insight into tourism practices across taxa. Clarifying the terminology describing these wildlife interactions ensures they can be accurately described in the scientific literature, which will in turn help resource managers and industry groups to systematically assess these diverse activities. [ABSTRACT FROM AUTHOR]

Effective species conservation requires the protection of all stages of its life-cycle. The Shark Reef Marine Reserve (SRMR) in Fiji is a marine protected area where large numbers of adult bull sharks (Carcharhinus leucas) congregate due to food provisioning. At the end of a calendar year bull sharks leave the area for reproductive activity, but parturition sites are still unknown. Between February 2014 and January 2015, we interviewed local fishermen and conducted a fishing survey, so as to assess presence and abundance of bull sharks in the Navua River near the SRMR. In total 84% of fishermen reported either seeing or catching sharks up to 8 kmupriver from the river mouth. They described them as small sharks having a rounded snout and being grey-brown in colour with a white belly, morphological characteristics that match juvenile bull sharks. During the fishing survey, a total of nine juvenile bull sharks were captured, including two that were recaptured after 108 and 92 days at liberty. Our findings confirmed the presence of bull sharks in the Navua River and provide a preliminary characterisation of a potential shark parturition or nursery area from a data-poor region. [ABSTRACT FROM AUTHOR]

This study used field data of echeneid and ectoparasite associations with free-swimming whale sharks (Rhincodon typus) and captured mako sharks (Isurus oxyrinchus) to test whether (1) echeneid presence was positively correlated with ectoparasite presence; and (2) the number of ectoparasites was negatively correlated with the number of echeneid fish. Data from whale and mako sharks do not support the first hypothesis whereas data from mako sharks yields support for the second hypothesis. The results indicate that echeneids do regulate the number of ectoparasites on at least some host species, but these benefits may be contingent on the echeneid species. [ABSTRACT FROM AUTHOR]