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Context: For sharks, information on the location and usage of critical habitats is rare. Marine protected areas (MPAs) have great potential to benefit shark populations but these rarely protect a species throughout its life stages or all critical habitats. The latter often includes parturition sites. Aims: Pregnant bull sharks from the Shark Reef Marine Reserve in Fiji were tracked into riverine systems during three parturition seasons. Methods: We tagged 31 female bull sharks with acoustic transmitters and placed acoustic receivers in the Rewa, Sigatoka, Navua and Ba Rivers on the island of Viti Levu between 2016 and 2018. Key results: Fourteen bull sharks were detected by receivers placed in the four rivers for few, typically consecutive days during parturition season. Bull sharks were detected in the Rewa River during all three parturition seasons whereas sharks were detected in the Navua River only during the 2017/2018 season. Conclusions: We have shown that Fiji's rivers are critical for the completion of the bull shark's life cycle. Implications: Fiji has recognized the importance of conserving its population of bull sharks. Our results call for the implementation of protective measures for the species' critical habitats. Knowing the locations of species' critical habitats from adult aggregation sites to parturition sites and nursery areas is important for implementing effective conservation measures. Here, we show that Fiji's rivers are critical for the completion of the bull shark's life cycle. Fiji's authorities are encouraged to implement regulatory safeguards to preserve and protect the Fijian bull shark population's critical habitats. [ABSTRACT FROM AUTHOR]

Context. Globally, more than 121 million people enjoy nature-based marine tourism, making it one of the largest marine industries. Ocean degradation threatens this industry and management has not kept pace to ensure long-term sustainability. In response, some individuals within the industry are taking it upon themselves to monitor the ocean and provide the data needed to assist management decisions. Fiji is one such place. Aims. Between 2012 and 2016, 39 Fijian dive operators, in collaboration with eOceans, conducted the Great Fiji Shark Count to document sharks on their dives. Methods. Using 146 304 shark observations from 30 668 dives, we document spatial and temporal patterns of 11 shark species at 592 sites. Key results. Sharks were observed on 13 846 dives (45% of recorded dives) at 441 (74%) sites. Generally, our results matched those from other more limited surveys, including from baited remote underwater video systems. We found high variability in shark presence, species richness, and relative abundance through space and time. One trend was surprising: the most common species, Whitetip Reef Shark, decreased over the study period at eastern sites and increased at western sites; the cause is currently unknown. Conclusions. Our results can guide management and conservation needs, future scientific questions, and provide a baseline for future assessments. Implications. This study demonstrates the value of longitudinal observation data that includes absences for describing marine fauna, and confirms the capacity of stakeholders to document the ocean. It also points the direction for broadscale participatory science methodologies to track the ocean. [ABSTRACT FROM AUTHOR]

Abstract: Wildlife tourism is often extolled for its contribution to conservation. However, understanding the effects of tourism activities on the health of target animals is required to fully assess conservation benefits. Shark tourism operators often use food rewards to attract sharks in close proximity to tourists, but nothing is known about the contribution of these food rewards to the energetic requirements of target species. In this study, hand feeding of bull sharks Carcharhinus leucas was directly observed on 36 commercial shark watching dives in the Shark Reef Marine Reserve (SRMR), Fiji. Mean number of tuna heads consumed per dive by focal individuals ranged from 1.3 to 3.7. Monitored bull sharks consumed an average of ~0.74 heads per provisioning day, and bioenergetics modelling suggests that some sharks might periodically be meeting their full energy requirement from provisioning at the SRMR. Knowing how much individual sharks consume at provisioning sites and how this relates to their energy requirements is crucial in order to better understand the effects of wildlife tourism and its contribution to conservation. [ABSTRACT FROM AUTHOR]

Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.

A set of 27 rice varieties were evaluated for their morphological grain characteristics (length, width, thickness, thousand kernel weight, TKW), chemical composition (amylose, protein, and ash content) and starch properties (gelatinization temperature and enthalpy, amylose-lipid complex). In addition, cell walls were characterized by the arabinoxylan and beta-glucan contents. A rapid method for determining optimum rice cooking time was developed based on the swelling ratio; a fixed value of 2.55 gave a gelatinization level of 95% assessed by differential scanning calorimetry and translucence testing. Optimum cooking time appears positively correlated with kernel thickness and TKW but also with ash content. Confocal laser and scanning electron microscope observation of uncooked rice grains revealed different structural features (cell size) and fracture behavior: for some cultivars, the fracture showed ruptured cells, whereas for others most cells were intact. These structural differences, which may be linked to pectin content, could partly explain rice kernel cooking behavior.