DNA evidence of whale sharks (Rhincodon typus) feeding on red crab (Gecarcoidea natalis) larvae at Christmas Island, Australia

2009 ◽  
Vol 60 (6) ◽  
pp. 607 ◽  
Author(s):  
M. G. Meekan ◽  
S. N. Jarman ◽  
C. McLean ◽  
M. B. Schultz

Whale sharks (Rhincodon typus) are thought to aggregate in nearshore waters around Christmas Island (105°37′E, 10o29′S) to consume the marine larvae of the endemic red land crab (Gecarcoidea natalis). However, there have been no direct observations of sharks feeding on crab larvae. Whale shark faeces were analysed using genetic testing to confirm the presence of crab larvae in their diet. Primers were designed for amplifying two Gecarcoidea natalis mitochondrial small-subunit (mtSSU) rDNA regions. Gel electrophoresis of polymerase chain reaction (PCR) products amplified from whale shark faecal DNA produced bands of the expected size for G. natalis templates. Specificity of both primer sets for G. natalis mtSSU rDNA was expected to be high from comparisons with mtSSU rDNA regions from closely related crabs and we confirmed their specificity empirically. The amplification of fragments from faecal DNA of the same size as those produced from G. natalis DNA indicates that the whale shark had been feeding on G. natalis and that enough of the crab DNA survived digestion to be detected by these PCRs. Our study provides further evidence that aggregations of whale sharks in coastal waters occur in response to ephemeral but predictable increases in planktonic prey.

2021 ◽  
Vol 21 (3) ◽  
pp. 199-213
Author(s):  
Yusup A Jentewo ◽  
Roni Bawole ◽  
Tresia S Tururaja ◽  
Mudjirahayu Mudjirahayu ◽  
Zeth Parinding ◽  
...  

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.


2016 ◽  
Vol 3 (11) ◽  
pp. 160455 ◽  
Author(s):  
Samantha Andrzejaczek ◽  
Jessica Meeuwig ◽  
David Rowat ◽  
Simon Pierce ◽  
Tim Davies ◽  
...  

Genetic and modelling studies suggest that seasonal aggregations of whale sharks ( Rhincodon typus ) at coastal sites in the tropics may be linked by migration. Here, we used photo-identification (photo-ID) data collected by both citizen scientists and researchers to assess the connectedness of five whale shark aggregation sites across the entire Indian Ocean at timescales of up to a decade. We used the semi-automated program I 3 S (Individual Interactive Identification System) to compare photographs of the unique natural marking patterns of individual whale sharks collected from aggregations at Mozambique, the Seychelles, the Maldives, Christmas Island (Australia) and Ningaloo Reef (Australia). From a total of 6519 photos, we found no evidence of connectivity of whale shark aggregations at ocean-basin scales within the time frame of the study and evidence for only limited connectivity at regional (hundreds to thousands of kilometres) scales. A male whale shark photographed in January 2010 at Mozambique was resighted eight months later in the Seychelles and was the only one of 1724 individuals in the database to be photographed at more than one site. On average, 35% of individuals were resighted at the same site in more than one year. A Monte Carlo simulation study showed that the power of this photo-ID approach to document patterns of emigration and immigration was strongly dependent on both the number of individuals identified in aggregations and the size of resident populations.


2013 ◽  
Author(s):  
Michael P Black ◽  
Matthew Grober ◽  
Christian Schreiber ◽  
Chris Coco ◽  
Alistair Dove

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.


2013 ◽  
Author(s):  
Michael P Black ◽  
Matthew Grober ◽  
Christian Schreiber ◽  
Chris Coco ◽  
Alistair Dove

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.


2018 ◽  
Vol 101 (8) ◽  
pp. 1285-1293 ◽  
Author(s):  
Cláudio L. S. Sampaio ◽  
Luciana Leite ◽  
José Amorim Reis-Filho ◽  
Miguel Loiola ◽  
Ricardo J. Miranda ◽  
...  

Oryx ◽  
2006 ◽  
Vol 40 (3) ◽  
pp. 337-342 ◽  
Author(s):  
Michelle M. Theberge ◽  
Philip Dearden

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.


Coral Reefs ◽  
2009 ◽  
Vol 28 (3) ◽  
pp. 577-577 ◽  
Author(s):  
J-P. A. Hobbs ◽  
A. J. Frisch ◽  
T. Hamanaka ◽  
C. A. McDonald ◽  
J. J. Gilligan ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jessica Harvey-Carroll ◽  
Joshua D. Stewart ◽  
Daire Carroll ◽  
Basith Mohamed ◽  
Ibrahim Shameel ◽  
...  

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.


Author(s):  
Elizabeth Clingham ◽  
Judith Brown ◽  
Leeann Henry ◽  
Annalea Beard ◽  
Alistair D Dove

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.


2020 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Budi Nugraha ◽  
Dharmadi Dharmadi ◽  
Ngurah N. Wiadnyana

Hiu paus merupakan salah satu jenis hiu berukuran terbesar yang ada di dunia dan sudah masuk dalam daftar merah (Red List) untuk spesies terancam IUCN yaitu berstatus terancam punah (endangered). Untuk menjaga agar sumber daya hiu paus tetap terjamin populasinya, maka perlu adanya upaya pengelolaan untuk mendukung pelestarian spesies ini. Dalam makalah ini dibahas tentang strategi pemanfaatan dan penanganan hiu paus yang terdampar di perairan Indonesia. Metode penelitian yang digunakan adalah survei lapang dan wawancara yang dilakukan di Probolinggo dan Situbondo, Jawa Timur. Data dan informasi dihimpun dari penelusuran, dan penelahaan data dan informasi hasil penelitian serta laporan kegiatan yang terkait dengan hiu paus terdampar maupun keberadaannya di beberapa wilayah perairan di Indonesia. Hasil kajian menunjukkan bahwa terdapat enam wilayah perairan kemunculan hiu paus di Indonesia, baik yang menetap maupun yang tinggal sementara yaitu di perairan Teluk Cendrawasih, Talisayan, Kaimana, Teluk Gorontalo, Probolinggo, dan Banggai Kepulauan. Jumlah hiu paus yang berada di perairan Indonesia dan tersebar di beberapa wilayah perairan diperkirakan mencapai 253 ekor. dan teramati terbanyak berada di perairan Teluk Cendrawasih sebanyak 131 ekor. Kemunculan hiu paus maupun yang terdampar hampir terjadi setiap tahun dalam kondisi hidup terkadang keadaan mati. Koordinasi antara instansi terkait dan masyarakat dalam menangani dan menyelamatkan hiu paus yang terdampar maupun terjerat jaring saat ini sudah berjalan dengan baik. Terdapat 7 tahapan tata cara penanganan hiu paus terdampar dan ada 4 tahapan dalam rangka menunjang ekowisata hiu paus.Whale shark is one of the largest sharks in the world and on the red list IUCN for endangered species. To ensure that the population of whale sharks remains guaranteed, management efforts are needed to support the conservation of this species. The utilization and handling strategy of the whale sharks that stranded down in several Indonesian waters should be discussed seriously. Field survey method was applied and interview was done in Probolinggo and Situbondo, East Java. Data and information were collected and had been analyzed as well as activities reported that related to whale sharks stranded and their presence in several territorial waters Indonesia waters. The results of the study showed that there were six Indonesia waters area in which whale sharks appeared, both permanent and temporary, namely in Cendrawasih Bay, Talisayan, Kaimana, Gorontalo, Probolinggo, and Banggai Islands. The whale shark number that found in several Indonesian waters had been estimated about 253  individuals and the highest number was found 131 in Cendrawasih Bay. The appearances of whale shark and stranded in Indonesian waters has been almost every year and found in living or in such cases been in dead conditions that trapped in the shallow area. Coordination between related agencies and the community to carry out and rescuing whale sharks stranded or entangled in nets, has been in good progress. There were 7 stages of procedures for handling stranded whale sharks and 4 stages in order to support the ecotourism activities that related with appearances of whale sharks.


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