New insights into whale shark Rhincodon typus diet in Brazil: an observation of ram filter-feeding on crab larvae and analysis of stomach contents from the first stranding in Bahia state

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.

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General descriptions of the dermis structure of a juvenile whale shark Rhincodon typus from the Gulf of California

Journal of Fish Biology ◽

10.1111/jfb.14827 ◽

2021 ◽

Author(s):

E. E. Becerril‐García ◽

F. Pancaldi ◽

A. A. Cruz‐Villacorta ◽

A. R. Rivera‐Camacho ◽

C. A. Aguilar‐Cruz ◽

...

Keyword(s):

Gulf Of California ◽

Whale Shark ◽

Rhincodon Typus

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The potential for expansion of whale shark (Rhincodon typus) tourism in St. Helena: stakeholder engagement and willingness to pay

Journal of Ecotourism ◽

10.1080/14724049.2021.1971684 ◽

2021 ◽

pp. 1-12

Author(s):

Joshua Drew ◽

Kenickie Andrews ◽

Ness Smith

Keyword(s):

Willingness To Pay ◽

Stakeholder Engagement ◽

Whale Shark ◽

Rhincodon Typus ◽

St Helena

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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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