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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.

Assessing the movements and connectivity of whale sharks Rhincodon typus through their range is difficult due to high individual mobility and limited knowledge of their behaviour following dispersal from coastal aggregation sites. Here, we use a large set of photo-identification and stable isotope data (δ15N and δ13C) to test the assumption that sharks frequenting aggregation sites in Mozambique, Tanzania, and Qatar are a mixed stock, as inferred by genetic data. Photo-identification revealed negligible connectivity among aggregation sites and none between the southern and central areas of the Western Indian Ocean (Mozambique and Tanzania) and the Arabian Gulf (Qatar). Sight−resight data indicated that shark movements at each site could be best represented by a model that included emigration, re-immigration, and some mortality or permanent emigration. Although there was high individual variation in the isotope profiles of sharks from each location, comparison with latitudinal isotope data suggests that sharks had shown site fidelity to within a few hundred kilometres of each study area over the period of isotopic integration. Given the Endangered status of whale sharks and regional differences in anthropogenic threat profiles, further studies — and conservation assessment efforts — should consider the possibility that whale shark subpopulations exist over smaller geographical scales than previously documented.

Whale sharks Rhincodon typus are large filter-feeders that are frequently observed feeding in surface zooplankton patches at their tropical and subtropical coastal aggregation sites. Using signature fatty acid (FA) analyses from their subdermal connective tissue and stomach content analysis, we tested whether whale sharks in Mozambique and South Africa predominantly feed on these prey and/or what other prey they target. Arachidonic acid (20: 4.6; mean +/- SD = 17.8 +/- 2.0% of total FA), 18: 0 and 18: 1.9c were major FA of whale sharks, while in contrast, coastal epipelagic zooplankton collected near feeding whale sharks had 22: 6.3 (docosahexaenoic acid), 16: 0 and 20: 5.3 (eicosapentaenoic acid) as major FA. Stomach contents of 3 stranded sharks were dominated by mysids (61 to 92% of prey items), another one by sergestids (56%), and a fifth stomach was empty. The dominant mysids (82% index of relative importance) were demersal zooplankton that migrate into the water column at night, suggesting night-time feeding by whale sharks. High levels of bacterial FA in whale sharks (5.3 +/- 1.4% TFA), indicating a detrital link, potentially via demersal zooplankton, also support night-time foraging activity. High levels of oleic acid (16.0 +/- 2.5%) in whale sharks and their similarity with FA profiles of shrimp, mysids, copepods and myctophid fishes from the meso-and bathypelagic zone suggest that whale sharks also forage in deep-water. Our findings suggest that, in the patchy food environment of tropical systems, whale sharks forage in coastal waters during the day and night, and in oceanic waters on deep-water zooplankton and fishes during their long-distance movements.

Invasive plants can have dramatic effects on natural ecosystems. It is unclear, though, whether these will have a positive or negative effect on animal species’ behavior and population parameters within ecosystems where invasive plants occur. Here, we use a 2-year time series of mouse trapping data to test the effects of an evergreen invasive shrub, Rhododendron ponticum, on population distribution and abundance in a population of wood mice (Apodemus sylvaticus) in southern England. Given the importance of aerial predators on rodent survival and the shield that the thick cover of Rhododendron branches and leaves provides, we predicted that Rhododendron would have a positive effect on mouse aggregation and abundance. The results confirmed both predictions: proximity to Rhododendron positively influenced mouse abundance, whereas a significant interaction between protective microhabitat features (logs) and Rhododendron suggest that reductions in predation risk drive the proximity results. In addition, as mouse densities increased, competition increased. During spring, when mouse territoriality was greatest, we found primarily large adults in the Rhododendron habitat, with subadult and juvenile mice more likely to be found away from Rhododendron patches. The effects of Rhododendron-driven increases in mouse density on lower (seed predation and dispersal) and upper trophic level (weasel populations) are also discussed. Questing tick’s density and invertebrate biomass were also lower under Rhododendron. Our research shows that an invasive plant species can increase the abundance of a native mammal and that this could potentially lead to increases/decreases in other species populations within the community. Key wor ds: Apodemus sylvaticus , edible invertebrate biomass, intraspecific competition, invasive shrub, predation risk, spatial variation, ticks, wood mouse. [Behav Ecol]

Background Mafia Island off the Tanzanian coast features a year-round resident whale shark population. Many of the sharks are seen regularly, making this a great natural laboratory to study their behaviour in detail. At the same time, whale sharks here also face threats locally from net entanglement and boat strike. We therefore set out to determine their fine-scale behaviour using novel telemetry methods in order to establish a profound baseline. Approach We conducted field work at Mafia Island from November–December 2015 and used 3D tags (Open Tags) and satellite tags (Desert Star SeaTagMODs) to examine whale shark behaviour. 3D tags recorded depth, temperature, acceleration as well as gyrometer and magnetometer readings at 200 data points per second. Satellite tags recorded depth, temperature, acceleration and geolocation. We attached 3D behavioural tags to the first dorsal fin using a padded clamp, and double-tagged some of the sharks with satellite tags attached with a titanium dart anchor and short tether. We manually retrieved both types of tags. A total of 117 hours of 3D tag data and 53 days of satellite tag data were recorded. Data were analysed in R. Results The attachment method using a padded clamp kept the tags in a stable position throughout their deployment period, although minor scarring of the fin was evident. We suggest some further improvements to the clamp to reduce scarring. Preliminary dive depth analysis of 3D tag data indicates that whale sharks largely stayed in shallow water, with an average swimming depth of just 4.7 m, SE: ± 0.008. The sharks also spent 10.4 hours, SD: ± 2.2 or 44.4% of the day swimming near or at the surface (depth < 2 m), indicating extensive surface feeding behaviour or surface swimming. We will clarify which behaviours were exhibited following further analysis of acceleration and gyrometer data. A simple one-way ANOVA revealed a significant difference between dive depth during the day and night (p < 0.005). During daytime, the deepest dive was to 18.8 m, with an overall mean depth of 3 m ± 0.007. The deepest recorded dive (29.8 m) occurred at night. Mean dive depth at night was two times higher, at 6.4 m ± 0.012. Time spent above 2 m was twofold higher during the day with 6.9 h ± 1.9 than at night with 3.5 h ± 1.2, indicating that a diel behavioural shift occurred. Conclusion 3D telemetry is an emerging technique that provides unprecedented insight into whale shark behaviour. Here, we show some initial results that indicate the potential applications for this technology. We will continue analysing gyrometer and acceleration data that allow us to further distinguish and quantify behaviours, such as feeding and search behaviour.

Background Off Mafia Island, Tanzania, whale sharks are seen in a small bay that also boasts one of the country's largest coastal fisheries. We set out to determine the population structure of whale sharks here, examine their feeding behaviour and residency, and investigate the interaction between the sharks and fishers. Approach We conducted 261 boat-based surveys at Mafia Island between Oct 2012 and Dec 2015, recording all whale shark sightings as well as counting the numbers of tourist and fishing boats in the survey area during each trip. We estimated shark size visually and with laser photogrammetry and recorded sex, scars and behaviour of each shark. To examine residency, we deployed 67 acoustic tags on whale sharks and 19 receiver stations within the bay, and analysed recapture probability (both visual- and acoustic-based) with generalised additive mixing models. To investigate feeding plankton biomass and community structure, we collected 20 plankton samples when whale sharks were feeding and 202 background samples for comparison. We interviewed fishers and they recorded their fishing locations using a GPS. Results We identified 129 different whale sharks at Mafia Island, 54% of which were resighted in two or more years. Tagged sharks were acoustically detected throughout the year even though sightings were largely limited to Oct-Mar. Sharks ranged in total length from 2.5–9.7 m, were mostly male (87%), and were usually seen feeding (75%) at or near the surface. Dense patches (25 mg m–3) of large sergestids Lucifer hanseni prompted feeding, while background plankton tows were dominated by small copepods (2.5 mg m–3). Small and medium-sized planktivorous fishes also fed on the same patches of sergestids, often together with whale sharks. These smaller species were the main target of the local fishers. Fishing boats operated in the survey area on 90% of the time, but also made catches further afield. Fishers reported a conflict between whale sharks and their fishing operations on 36% of the time, although sharks were usually released from the nets without injury. A mean of 2.6 tourist boats per day searched the same survey area for whale sharks. Conclusions This small, resident group of whale sharks is routinely exposed to tourists, boat traffic and high fishing pressure. Whale sharks are commonly encircled in fishing nets and released, but scars indicate that they do occasionally get injured during this process. Mortalities are rare, based on interviews with fishers and long-term observers. Whale sharks at Mafia Island are unusually resident and face clear local threats. No defined management measures are currently in place, but we present some potential strategies for mitigating threats to whale sharks here.

Background Mostdirectobservations of whale sharks occur at coastal feeding aggregation sites. The dominant food source in a feeding aggregation can often be quickly identified. However, there is a risk that short-term studies provide an unrepresentative snapshot of the sharks' long-term diet. Stable isotope analysis enables researchers to examine time-integrated results. Whale sharks at Mafia Island show a high degree of site fidelity. This provides a rare opportunity to study consistency, and changes over time, in individual trophic level and diet over a multi-year timescale. Approach Skinbiopsies were collected from free-swimming whale sharks between October 2011 and December 2014. Each shark was individually identified, sexed, and had their length estimated visually and/or with laser photogrammetry. Surface plankton was collected to measure the baseline isotopic signal. Additional samples from other local species from varying trophic levels were taken, including other planktivorous fishes, jellyfish, and piscivorous fishes. Targeted hand tows of the dominant food source in season, the sergestid shrimp Lucifer hanseni, were collected to investigate the longer term importance of this food source. The stable isotope composition of carbon and nitrogen were determined for all samples. Results Wewill be presenting preliminary results from this study. Throughout the sampling period we collected 223 skin biopsies from 79 individual sharks, 75% of which were male. Total lengths of all sampled sharks ranged from 4.5 to 8 m. One hundred and seventy two samples of zooplankton and other local species were collected. Overall there were no highly significant effects of the year of sampling of the sharks on δC13 (ANOVA p = 0.041) or δN15 (p > 0.05). Mean whale shark δN15 value (9.3 ± 0.07%) was similar to the other local planktivorous fishes sampled (Rastrelliger.k 10.79 ± 0.33%, and Hemiramphus sp. 10.84 ± 0.42%). There was considerable overlap of points in the δC13~δN15 biplot. The δC13 values of the sharks (–17.04 ± 0.07%) were, however, more enriched than the L. hanseni dominated surface zooplankton prey (–26.9 ± 0.38%). Whale sharks exhibited a wide range in δC13 values (–19.62 to 14.68%), and δN15 values (7.29 – 11.64%). Conclusions Thenumber of individuals sampled represents 60% of the identified population at Mafia Island, and as such this provides a unique opportunity to assess diet across a broad spectrum of the sharks that are routinely present. Initial results suggest no significant differences in feeding preference of the sharks over the three year study period. The broad range of both δC13 and δN15 is wider than seasonal changes reported in other elasmobranchs, so likely represents varied individual diets. The sharks appear to be feeding at the same trophic level as the other planktivorous fishes within this ecosystem. We will support these results by calculating an estimate of the trophic position of the sharks. The proximity and overlap of the whale shark isotope results compared to local planktivores suggests a high level of residency over the study period, which is further supported by photo-ID and acoustic telemetry. To corroborate this result we will be calculating the isotopic niche width using Bayesian ellipses framework in the SIBER package in R. Though the sharks may be highly resident, the enriched δC13 values of the sharks with respect to the surface zooplankton suggests they also have a more benthic or mesopelagic food source in their diet along with the seasonally abundant L. hansenii.

Background Research efforts on whale sharks have so far been limited to sub-adult males which make-up the vast majority of aggregations around the world. The movements of mature sharks, their reproductive techniques and key habitats remain poorly understood, whilst details of this demographic group are the most important to mitigate current threats. This quandary qualifies the use of indirect analyses such as genetic inference to characterise cryptic life-stages of the species. Approach Tissue samples will be collected from free-swimming whale sharks from locations around the WIO with past biopsy efforts providing additional tissue from every tropical ocean. Photographic identification, approximate visual size and gender information will be recorded for each individual. Microsatellite markers will be extracted from the samples using species-specific primers from previous studies. Additional open access sequences will be obtained via GenBank for appropriate locations. Software packages simulating modes of inheritance such as GERUD will be used to reconstruct parental genotypes. Results This is an outline of potential results of the study. Parental genotype reconstruction can provide information on: 1) Number of parents per litter – maternal genotypes will be reconstructed first as the likelihood of sampling littermates is higher than sampling offspring from different females who happened to mate with the same male. Paternal genotypes can be determined once the maternal genotypes are removed from the progeny sequences. 2) Juvenile recruitment – survival rate of individuals per litter, considering however that juvenile female whale sharks are underrepresented in the majority of sampling areas. Incomplete reconstruction of a parental genotype suggests incomplete offspring sampling. 3) Reproductive mode – i.e. monoor polyandry, demonstrated by single or multiple male genotypes per litter (respectively), which may confirm or refute the single only other demonstration of reproductive mechanism, monandry, in the species. 4) Breeding site fidelity – common and complete parental genotypes of either or both parents within an aggregation or in associated areas (assuming monandry) suggests that whale sharks return to or remain in a common area to pup whereas multiple incomplete genotypes may suggest random dispersal from any given pupping site. Conclusions The reproductive patterns of mature sharks, as inferred by these analyses, will define whale shark movements within their circumglobal range and may highlight important habitats such as breeding or pupping grounds. Resources for protecting the species will be limited and so must target these groups and areas to be most effective at mitigating threats and conserving the species.

Although whale sharks ( Rhincodon typus ) have been documented to move thousands of kilometres, they are most frequently observed at a few predictable seasonal aggregation sites. The absence of sharks at the surface during visual surveys has led to the assumption that sharks disperse to places unknown during the long ‘off-seasons’ at most of these locations. Here we compare 2 years of R. typus visual sighting records from Mafia Island in Tanzania to concurrent acoustic telemetry of tagged individuals. Sightings revealed a clear seasonal pattern with a peak between October and February and no sharks observed at other times. By contrast, acoustic telemetry demonstrated year-round residency of R. typus . The sharks use a different habitat in the off-season, swimming deeper and further away from shore, presumably in response to prey distributions. This behavioural change reduces the sharks' visibility, giving the false impression that they have left the area. We demonstrate, for the first time to our knowledge, year-round residency of unprovisioned, individual R. typus at an aggregation site, and highlight the importance of using multiple techniques to study the movement ecology of marine megafauna.

Large planktivores require high-density prey patches to make feeding energetically viable. This is a major challenge for species living in tropical and subtropical seas, such as whale sharks Rhincodon typus. Here, we characterize zooplankton biomass, size structure and taxonomic composition from whale shark feeding events and background samples at Mafia Island, Tanzania. The majority of whale sharks were feeding (73%, 380 of 524 observations), with the most common behaviour being active surface feeding (87%). We used 20 samples collected from immediately adjacent to feeding sharks and an additional 202 background samples for comparison to show that plankton biomass was ∼10 times higher in patches where whale sharks were feeding (25 vs. 2.6 mg m−3). Taxonomic analyses of samples showed that the large sergestid Lucifer hanseni (∼10 mm) dominated while sharks were feeding, accounting for ∼50% of identified items, while copepods (

Whale sharks Rhincodon typus are globally threatened, but a lack of biological and demographic information hampers an accurate assessment of their vulnerability to further decline or capacity to recover. We used laser photogrammetry at two aggregation sites to obtain more accurate size estimates of free-swimming whale sharks compared to visual estimates, allowing improved estimates of biological parameters. Individual whale sharks ranged from 432–917 cm total length (TL) (mean ± SD = 673 ± 118.8 cm, N = 122) in southern Mozambique and from 420–990 cm TL (mean ± SD = 641 ± 133 cm, N = 46) in Tanzania. By combining measurements of stranded individuals with photogrammetry measurements of free-swimming sharks, we calculated length at 50% maturity for males in Mozambique at 916 cm TL. Repeat measurements of individual whale sharks measured over periods from 347–1,068 days yielded implausible growth rates, suggesting that the growth increment over this period was not large enough to be detected using laser photogrammetry, and that the method is best applied to estimating growth rates over longer (decadal) time periods. The sex ratio of both populations was biased towards males (74% in Mozambique, 89% in Tanzania), the majority of which were immature (98% in Mozambique, 94% in Tanzania). The population structure for these two aggregations was similar to most other documented whale shark aggregations around the world. Information on small (