Movements and habitat use of satellite-tagged whale sharks off western Madagascar

Whale sharks Rhincodon typus, the world’s largest fish, are routinely sighted off the northwest coast of Madagascar, particularly off the island of Nosy Be. Dedicated whale shark tourism has been developing in the area since 2011. During our first dedicated survey, from September-December 2016, we photo-identified 85 individual whale sharks, ranging from 3.5–8 m in total length (all juveniles). None had been previously identified from other known whale shark aggregations. We tagged eight sharks with tethered SPOT5 tags in October 2016, with tracking durations of 9–199 days. Kernel density plots showed that the main activity hotspot for tagged sharks was around the Nosy Be area. Three individuals were resighted back at Nosy Be in late 2017, after having lost their tags. A secondary hotspot was identified off Pointe d’Analalava, 180 km southeast of Nosy Be. Five sharks swam off the shelf into the northeastern Mozambique Channel, between Madagascar and Mayotte, and one of these continued to near the Comoros islands. Two sharks swam to southern Madagascar, with minimum track distances of 3414 km and 4275 km. The species is presently unprotected in Madagascar, although a small proportion of the high-use area we identified in this study is encompassed within two marine protected areas adjacent to Nosy Be. Whale sharks are globally endangered, and valuable to the local economy, so there is a clear rationale to identify and mitigate impacts on the sharks within the two hotspots identified here.

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Changes in diving behaviour and habitat use of provisioned whale sharks: implications for management

Scientific Reports ◽

10.1038/s41598-020-73416-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Gonzalo Araujo ◽

Jessica Labaja ◽

Sally Snow ◽

Charlie Huveneers ◽

Alessandro Ponzo

Keyword(s):

Endangered Species ◽

Habitat Use ◽

Metabolic Rate ◽

Sustainable Tourism ◽

Diving Behaviour ◽

Whale Shark ◽

Rhincodon Typus ◽

The World ◽

Whale Sharks ◽

Temperature Depth

Abstract Whale shark (Rhincodon typus) tourism is increasingly popular at predictable aggregations around the world, but only a few use provisioning to ensure close interactions. Understanding the effects of provisioning on the behaviour of this endangered species is critical to manage this growing industry. We recorded the diving behaviour and habitat use of juvenile whale sharks (n = 4) for a mean of 49.5 provisioned and 33.8 non-provisioned days using temperature-depth-recorders. We found that time spent at the surface (< 2 m) between 6 am and 1 pm increased ~ sixfold, while timing of deep dives shifted from 4–10 am to 10 am–2 pm, i.e. near or at the end of the provisioning activities. The shift might be related to a need to thermoregulate following a prolonged period of time in warmer water. These changes could have fitness implications for individuals frequently visiting the provisioning site. Based on recorded amount of time spent in warm waters and published Q10 values for ectotherms, we estimate a 7.2 ± 3.7% (range 1.3–17.8%) higher metabolic rate when sharks frequent the provisioning site. The observed behavioural, habitat use, and potential fitness shifts should be considered when developing guidelines for sustainable tourism, particularly in light of new provisioning sites developing elsewhere.

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Seasonal Occurrence, Horizontal Movements, and Habitat Use Patterns of Whale Sharks (Rhincodon typus) in the Gulf of Mexico

Frontiers in Marine Science ◽

10.3389/fmars.2020.598515 ◽

2021 ◽

Vol 7 ◽

Author(s):

Eric R. Hoffmayer ◽

Jennifer A. McKinney ◽

James S. Franks ◽

Jill M. Hendon ◽

William B. Driggers ◽

...

Keyword(s):

Gulf Of Mexico ◽

Habitat Use ◽

Continental Shelf ◽

Site Fidelity ◽

Seasonal Occurrence ◽

Whale Shark ◽

Shelf Edge ◽

Rhincodon Typus ◽

Aggregation Site ◽

Whale Sharks

In the northern Gulf of Mexico (GOM), whale sharks (Rhincodon typus) form large aggregations at continental shelf-edge banks during summer; however, knowledge of movements once they leave aggregation sites is limited. Here we report on the seasonal occurrence of whale sharks in the northern GOM based on over 800 whale shark sightings from 1989 to 2016, as well as the movements of 42 whale sharks tagged with satellite-linked and popup satellite archival transmitting tags from 2008 to 2015. Sightings data were most numerous during summer and fall often with aggregations of individuals reported along the continental shelf break. Most sharks (66%) were tagged during this time at Ewing Bank, a known aggregation site off the coast of Louisiana. Whale shark track duration ranged from three to 366 days and all tagged individuals, which ranged from 4.5 to 12.0 m in total length, remained within the GOM. Sightings data revealed that whale sharks occurred primarily in continental shelf and shelf-edge waters (81%) whereas tag data revealed the sharks primarily inhabited continental slope and open ocean waters (91%) of the GOM. Much of their time spent in open ocean waters was associated with the edge of the Loop Current and associated mesoscale eddies. During cooler months, there was a net movement southward, corresponding with the time of reduced sighting reports. Several sharks migrated to the southwest GOM during fall and winter, suggesting this region could be important overwintering habitat and possibly represents another seasonal aggregation site. The three long-term tracked whale sharks exhibited interannual site fidelity, returning one year later to the vicinity where they were originally tagged. The increased habitat use of north central GOM waters by whale sharks as summer foraging grounds and potential interannual site fidelity to Ewing Bank demonstrate the importance of this region for this species.

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Sizing and scarring of whale shark (Rhincodon typus Smith, 1828) in the Cenderawasih Bay National Park

Jurnal Iktiologi Indonesia ◽

10.32491/jii.v21i3.587 ◽

2021 ◽

Vol 21 (3) ◽

pp. 199-213

Author(s):

Yusup A Jentewo ◽

Roni Bawole ◽

Tresia S Tururaja ◽

Mudjirahayu Mudjirahayu ◽

Zeth Parinding ◽

...

Keyword(s):

National Park ◽

The Body ◽

Whale Shark ◽

Gill Slit ◽

Rhincodon Typus ◽

Photo Identification ◽

Dorsal Fin ◽

Total Length ◽

Whale Sharks ◽

Photo Collection

This study aims to determine the total length and scar condition of the body of whale sharks (Rhincodon typus) in Cendrawasih Bay National Park (TNTC), Papua-Indonesia. Photo-identification was used to identify individuals of the whale shark R. typus based on spot patterns behind the last gill slit of each individual. Photo-identification was also used to determine the scar of the whale shark. The total length of whale sharks were estimated based on the length of a snorkeller (assumed to be 1.6 m) swimming alongside the whale shark. We identified 21 individuals of R. typus. Of these 21 individuals, 14 were new sightings and seven were re-sightings that have been recorded in the previous photo collection database. R. typus ranged in size from 2 to 5 m total length (average 3.78 m, ±0,86, N= 21). Based on their size, all individuals of whale shark were categorized as juvenile. 52% of R. typus identified had scars and 38 % were not and 10% were unknown. The majority of whale sharks had amputation (12 individuals) and abrasion (7 individuals) scars. Scars occurred most often on the caudal fin and dorsal fin, five and four individuals respectively. This information is useful for understanding potential threats and designing better management programmes for R. typus conservation in TNTC.

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Whale shark (Rhincodon typus) behavior: A multi-year analysis of individuals at Georgia Aquarium

10.7287/peerj.preprints.88 ◽

2013 ◽

Author(s):

Michael P Black ◽

Matthew Grober ◽

Christian Schreiber ◽

Chris Coco ◽

Alistair Dove

Keyword(s):

Feeding Time ◽

Whale Shark ◽

Short Term ◽

Behavioral Profile ◽

Behavioral Traits ◽

Rhincodon Typus ◽

In Captivity ◽

Whale Sharks ◽

Daily Changes

Background. From the coastal seas near Taiwan to the 6.3 million gallon Ocean Voyager habitat at Georgia Aquarium in Atlanta, Georgia, whale sharks, Rhincodon typus, were brought in stages: two females arrived in June 2006 and two males in June 2007. The behavioral observations described in this study began in 2008 as the first reported observations in captivity to assist in husbandry and better understand whale shark behavior variation between individuals and across time. Methods. Two types of observations were made of the four sharks currently in the Georgia Aquarium Ocean Voyager habitat: 1) 15-minute focal observations throughout the day of individual sharks from a high gantry vantage point using Stopwatch+ software to time stamp all recorded behavior and 2) observations of swim speed, depth, and swimming direction for all sharks passing by a section of wall over longer periods of time (15 min-hours). Z-tests were used for inter-observer reliability. Results. For most traits, whale sharks demonstrated unique behavioral profiles that were consistent over many years, but, over the course of years, some of these behavioral traits changed for individual sharks. There were also daily changes in behavior that were consistent across days. For instance, whale sharks showed a clear anticipation of feeding time marked by increases in swimming speed prior to obvious cues of the feed (i.e. 1 hour prior). During observations recorded during the day, whale sharks spent the majority of their time swimming at or near the surface. Most spent relatively equal times swimming clockwise as they did counterclockwise. Swim speeds observed in the habitat were similar to the range of those estimated from work in the field. Conclusion. Each shark in the habitat demonstrated a behavioral profile unique to that individual, and we have observed short-term and long-term consistent patterns as well as changes in some behavior. These observations increase our knowledge of whale shark behavior, assisting in the husbandry of these animals and giving a better understanding of individual differences, temporal changes, and interactions between sharks.

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Whale shark (Rhincodon typus) behavior: A multi-year analysis of individuals at Georgia Aquarium

10.7287/peerj.preprints.88v1 ◽

2013 ◽

Author(s):

Michael P Black ◽

Matthew Grober ◽

Christian Schreiber ◽

Chris Coco ◽

Alistair Dove

Keyword(s):

Feeding Time ◽

Whale Shark ◽

Short Term ◽

Behavioral Profile ◽

Behavioral Traits ◽

Rhincodon Typus ◽

In Captivity ◽

Whale Sharks ◽

Daily Changes

Background. From the coastal seas near Taiwan to the 6.3 million gallon Ocean Voyager habitat at Georgia Aquarium in Atlanta, Georgia, whale sharks, Rhincodon typus, were brought in stages: two females arrived in June 2006 and two males in June 2007. The behavioral observations described in this study began in 2008 as the first reported observations in captivity to assist in husbandry and better understand whale shark behavior variation between individuals and across time. Methods. Two types of observations were made of the four sharks currently in the Georgia Aquarium Ocean Voyager habitat: 1) 15-minute focal observations throughout the day of individual sharks from a high gantry vantage point using Stopwatch+ software to time stamp all recorded behavior and 2) observations of swim speed, depth, and swimming direction for all sharks passing by a section of wall over longer periods of time (15 min-hours). Z-tests were used for inter-observer reliability. Results. For most traits, whale sharks demonstrated unique behavioral profiles that were consistent over many years, but, over the course of years, some of these behavioral traits changed for individual sharks. There were also daily changes in behavior that were consistent across days. For instance, whale sharks showed a clear anticipation of feeding time marked by increases in swimming speed prior to obvious cues of the feed (i.e. 1 hour prior). During observations recorded during the day, whale sharks spent the majority of their time swimming at or near the surface. Most spent relatively equal times swimming clockwise as they did counterclockwise. Swim speeds observed in the habitat were similar to the range of those estimated from work in the field. Conclusion. Each shark in the habitat demonstrated a behavioral profile unique to that individual, and we have observed short-term and long-term consistent patterns as well as changes in some behavior. These observations increase our knowledge of whale shark behavior, assisting in the husbandry of these animals and giving a better understanding of individual differences, temporal changes, and interactions between sharks.

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Detecting a decline in whale shark Rhincodon typus sightings in the Andaman Sea, Thailand, using ecotourist operator-collected data

Oryx ◽

10.1017/s0030605306000998 ◽

2006 ◽

Vol 40 (3) ◽

pp. 337-342 ◽

Cited By ~ 38

Author(s):

Michelle M. Theberge ◽

Philip Dearden

Keyword(s):

Data Collection ◽

Andaman Sea ◽

Whale Shark ◽

Rhincodon Typus ◽

Global Conservation ◽

Whale Sharks

In this paper, we analyse long-term whale shark Rhincodon typus sightings collected by ecotourist operators and evaluate the validity of conclusions drawn from the data for scientific and conservation purposes. To date information about the basic ecology and movements of whale sharks is sparse, and only recently has the species received global conservation attention. A dive company in Phuket, Thailand, documented whale shark sightings in the Andaman Sea for 10 years along 300 km of coastline. Whale shark sightings, corrected for effort, dropped by 96% between 1998 and 2001. Combining the seasons from 1992 to 1998, the number of whale shark sightings increased significantly from October to May. The sizes of sharks observed suggest that the majority were juveniles. We discuss the limitations of using ecotourist operators as non-specialist volunteers for data collection but conclude that their use can be beneficial for long-term, broad geographic studies such as this.

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The impact of injury on apparent survival of whale sharks (Rhincodon typus) in South Ari Atoll Marine Protected Area, Maldives

Scientific Reports ◽

10.1038/s41598-020-79101-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jessica Harvey-Carroll ◽

Joshua D. Stewart ◽

Daire Carroll ◽

Basith Mohamed ◽

Ibrahim Shameel ◽

...

Keyword(s):

Endangered Species ◽

Protected Area ◽

Local Community ◽

Marine Protected Area ◽

Conservation Strategies ◽

Whale Shark ◽

Apparent Survival ◽

Rhincodon Typus ◽

Whale Sharks ◽

The Impact

AbstractThe whale shark (Rhincodon typus) is an endangered species with a declining global population. The South Ari Atoll Marine Protected Area (SAMPA), Maldives, is one of few locations globally where year-long residency of individuals occurs. This SAMPA aggregation appears to consist almost exclusively of immature males. Due to its year-round residency, this local aggregation is subjected to a high degree of tourism pressure. This ecotourism contributes to the high level of interest and protection offered to whale sharks by the local community. Unfortunately, if regulations are not followed or enforced, tourism can bring with it major stressors, such as accidental injuries. We used POPAN capture-mark-recapture models and lagged identification rate analysis to assess the effect of major injuries on whale shark residency within SAMPA. Injuries may be obtained outside SAMPA. We found individuals with major injuries had a higher apparent survival in the area than those without. Lagged identification rates also demonstrated that sharks with major injuries are more likely to return to the area. We suggest that major injuries result in sharks prolonging their time in the developmental habitat. These findings have implications for individual fitness and the population viability of this endangered species. We propose targeted conservation strategies be considered to protect sharks from further injury. Based on the presented spatio-temporal distributions of sharks, and current local knowledge of sighting patterns, speed limit zones and propeller-exclusion zones should be implemented and enforced. If carried out alongside tourist education, these measures will contribute to the protection of whale sharks within SAMPA and beyond. Furthermore, our results can aid research direction, alongside regulation and enforcement development, at similar sites worldwide.

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Evidence that St. Helena island is an important multi-use habitat for whale sharks, Rhincodon typus, with the first description of putative mating in this species

10.7287/peerj.preprints.1885v1 ◽

2016 ◽

Cited By ~ 1

Author(s):

Elizabeth Clingham ◽

Judith Brown ◽

Leeann Henry ◽

Annalea Beard ◽

Alistair D Dove

Keyword(s):

Ad Hoc ◽

Mating Behaviour ◽

Public Awareness ◽

Behavioural Ecology ◽

Whale Shark ◽

Rhincodon Typus ◽

Pregnant Females ◽

Contact Behaviour ◽

Whale Sharks ◽

St Helena

Preliminary observations of whale shark behavioural ecology are presented from St. Helena, a remote volcanic island in the South Atlantic. Whale shark sightings by fishers, government biologists and the general public have been recorded by the St. Helena Government since February 1999 and are presented here through to the end of 2014. A total of 328 sightings was collected on an ad hoc basis, a total of 931 animals, although the number of re-sightings within that total is not known. Increases in observations are likely coincident with increases in surveillance and public awareness of the presence of this species in the waters surrounding St Helena. On two occasions, small aggregations of whale sharks were observed at the bay at Jamestown; the animals were engaged in surface feeding behaviour similar to that seen in coastal aggregations in Mexico and Qatar. In contrast to other aggregations, however, animals observed at St Helena were numerically dominated by adult females, although mature males and some juveniles have also been observed. On two occasions, eyewitness accounts of mating behaviour were reported by two different reliable observers. These events took place in 2005 and 2007, both approximately 16 kilometers from shore, at different sites. They both involved belly-to-belly contact behaviour at the surface, in one case involving at least two males. This is the first report of putative mating behaviour in the whale shark. With the presence of both adult and juvenile animals, surface feeding aggregations, apparently pregnant females and the first observations of putative mating, the waters around St Helena are clearly an important multi-use habitat for whale sharks and are worthy of concerted conservation efforts.

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Seasonal habitat use of whale sharks in the northern Gulf of Mexico, USA 2003 - 2013

10.7287/peerj.preprints.93v1 ◽

2013 ◽

Author(s):

Jennifer A McKinney ◽

Eric R Hoffmayer ◽

Jim S Franks ◽

Jill M Hendon ◽

William B Driggers

Keyword(s):

Home Range ◽

Gulf Of Mexico ◽

Habitat Use ◽

Whale Shark ◽

Shelf Edge ◽

Northern Gulf Of Mexico ◽

Use Patterns ◽

Core Habitat ◽

Whale Sharks ◽

Satellite Tagging

Background: Reports of whale sharks (Rhincodon typus) in the northern Gulf of Mexico (GOM) date back to the 1930s. In 2003, the Northern Gulf of Mexico Whale Shark Research Program was established and began making directed efforts to document the regional occurrence, seasonal distribution and habitat preferences of whale sharks. Methods: Whale shark sightings data (WSS: 1989 – present; n=644) and tagging geoposition data (TD: 2009-2012; n=450) were used in seasonal kernel density (KD) analyses to delineate home range (95%) and core habitat (50%) use areas in the northern GOM. Kernel density estimation of distribution is a statistically robust manner of handling data sources with differing sampling designs (anecdotal vs. directed). Habitat use patterns from the two datasets were used to identify critical use areas. Results: In the study area, whale shark home range was 276,000 km2 (WSS) to 369,000 km2 (TD) in size, with 52,000 km2 (WSS) to 62,000 km2 (TD) being core habitat. Whale shark habitat use varied seasonally, with the largest home range occurring during summer (WSS: 213,000 km2) and fall (TD: 221,000 km2). Tag data revealed more winter habitat (75,000 km2) than the sightings dataset (41,000 km2), which was shifted further offshore to slope waters. Significant use patterns occurred along the continental shelf-edge, encompassing shelf-edge banks south of Louisiana, and near the mouth of the Mississippi River. Conclusions: The combination of sightings data and satellite tagging data represents an effective methodology for assessing seasonality of occurrence, distribution, and habitat use of whale sharks. Shelf-edge bank habitats were most commonly used by whale sharks in the region. Satellite tagging data provided additional evidence of connectivity between multiple jurisdictions, which lends support for international management of the species.

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