The first record, tagging and release of a neonatal whale shark <i>Rhincodon typus</i> in Taiwan

Hsu, Hua Hsun; Lin, Chia-Yen; Joung, Shoou‐Jeng

doi:10.1111/jfb.12498

Cited by 6 publications

(7 citation statements)

References 11 publications

(18 reference statements)

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“…Conversely, the presence of gravid females in oceanic regions, such as Baja California Sur [18,37] and Galapagos Islands [36], St Helena [38] and now the ASPSP, and the concurrent occurrence of small juveniles in areas from major ocean basins such as Indian (Djibouti [82]; India, Pakistan, Bangladesh and Seychelles [101]); Indo-Pacific (Philippines [102]; Taiwan [103]); Pacific (open ocean [104]) and Atlantic (equatorial open ocean [104,105]; ASPSP ([25]; present study), provides clues to where reproductive activity may occur worldwide.…”

Section: Discussionmentioning

confidence: 99%

Whale Shark (Rhincodon typus) Seasonal Occurrence, Abundance and Demographic Structure in the Mid-Equatorial Atlantic Ocean

Macena

Hazin

2016

PLoS ONE

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Whale sharks are generally associated with environmental factors that drive their movements to specific locations where food availability is high. Consequently, foraging is believed to be the main reason for the formation of whale shark aggregations. Feeding aggregations occur mainly in nearshore areas and are composed primarily of immature individuals. Conversely, aggregations of mature adults are rarely observed, and their occurrence is correlated with oceanic environments. Despite an increase in the number of whale shark studies, information on mating and parturition grounds is still lacking. In the present work, we assessed the ecological and behavioural aspects of the whale sharks that visit the archipelago of São Pedro and São Paulo (ASPSP), located ~1,000 km off the coast of Brazil in the equatorial Atlantic Ocean. Forty-nine whale sharks were recorded from February 2005 to May 2014. The estimated mean ± SD size was 8.27 ± 2.52 m (range: 2.5–14.0 m) with no significant differences in size across the year. The maturational stages were classified by size as immature (<8.0 m; 32.56%) and mature (>9.0 m; 46.51%); with almost half of the observed animals being mature specimens. The majority of sightings occurred between February and June. During this period, the ocean current weakens and the waters are enriched by eggs and larvae of fishes and invertebrates that attract marine life to forage. At the same time, evidence of reproductive activity in adult females (i.e. swollen abdomen and bite marks on the pectoral fins), and the potential mating behaviour exhibited by one male, suggest that the ASPSP area might also have a role in whale shark reproduction. Irrespective of its use for feeding or reproduction, this insular habitat serves as a meeting point for both juvenile and adult whale sharks, and may play an important ecological role for the species.

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Section: Discussionmentioning

confidence: 99%

Whale Shark (Rhincodon typus) Seasonal Occurrence, Abundance and Demographic Structure in the Mid-Equatorial Atlantic Ocean

Macena

Hazin

2016

PLoS ONE

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“…The reproductive biology and mating habits of whale sharks remains elusive, with few clues based on chance encounters. Neonate records from the Philippines (Aca and Schmidt 2011), Taiwan (Hsu et al 2014), the northern Indian Ocean (Rowat et al 2008), St Lucia in the Caribbean (https://www.facebook.com/SCUBASTLUCIA/?fref=photo), and the Maldives (http://www.haveeru.com.mv/news/57774) combined with the capture of the pregnant individual off Taiwan (Joung et al 1996) may indicate a pupping area close to these locations. However, staggered (see Schmidt et al 2010) and potentially long gestation strongly argues against specific pupping grounds, as does the fact that any neonates found have been singles and perhaps doubles at most.…”

Section: International Resightingsmentioning

confidence: 99%

Undersea Constellations: The Global Biology of an Endangered Marine Megavertebrate Further Informed through Citizen Science

Norman¹,

Holmberg²,

Arzoumanian³

et al. 2017

BioScience

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The whale shark is an ideal flagship species for 'citizen science' projects because of its charismatic nature, regular presence at numerous coastal aggregation sites and a growing number of ecotourism ventures focusing on the species. An online database of Whale Shark encounters, identifying individuals based on their unique skin patterning from 1992 to 2014 captured almost 30,000 whale shark encounter reports, comprising more than 6000 individuals identified from 54 countries. In this time the number of known whale shark aggregation sites increased from 13 to 20. Examination of encounters revealed a skewed sexratio bias towards males (overall >66%), high site fidelity amongst individuals with limited movements of sharks between neighbouring countries/regions but no records confirming 2 large, ocean basin-scale migrations. Citizen science has been vital in amassing large spatial and temporal datasets to elucidate key aspects of whale shark life-history and demographics and will continue to provide substantial long-term value.

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“…However, perhaps a reflection of the difficulty of lethal sampling and long-term observations (Nozu et al 2015), the drivers of aggregations remain poorly understood. Juvenile R. typus are rarely observed (Rowat et al 2008, Aca and Schmidt 2011, Hsu et al 2014b, and mating and birthing has never been recorded. While some aggregations may be for the purpose of reproduction (Macena and Hazin 2016), many seem to be a response to seasonally enhanced feeding opportunities.…”

Section: Introductionmentioning

confidence: 99%

“…, Aca and Schmidt , Hsu et al. ), and mating and birthing has never been recorded. While some aggregations may be for the purpose of reproduction (Macena and Hazin ), many seem to be a response to seasonally enhanced feeding opportunities.…”

Section: Introductionmentioning

confidence: 99%

Enhancing insights into foraging specialization in the world's largest fish using a multi‐tissue, multi‐isotope approach

Wyatt

Matsumoto

Chikaraishi

et al. 2019

Ecological Monographs

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Intra‐species variability in foraging strategies may be common, which has significant implications for efforts to understand and manage enigmatic species like the whale shark Rhincodon typus. The ecological relevance of differences in tissue isotopes within and between individuals in the context of foraging however depends on understanding tissue turnover times and carbon (Δ13C) and nitrogen (Δ15N) discrimination, which can vary with physiology, metabolism, and diet quality. Here, we examine isotope dynamics in captive R. typus as a basis for enhanced ecological insights into wild populations of the world's largest fish and other enigmatic species. A variable diet, principally consisting of two krill (Euphausia pacifica and Euphausia superba) provided an average of 48 ± 20 MJ/d (mean ± SD), or 2.7 ± 1.3 times basal metabolic requirements. On this diet, in agreement with allometric relationships, large body sizes (3,000–4,000 kg) were matched by slow plasma and cartilage turnover rates (empirically derived as 9 months and 3 yr, respectively), which provide tissue‐specific limits on the timescales over which we can isotopically detect diet changes in this species. Average diet‐to‐tissue discrimination showed significant variation between tissues (plasma and cartilage), and among growing and fasting individuals (Δ13C range, 1.5 to 5.5‰; Δ15N range, −0.1 to 2.9‰). Assimilation rates increased with temperature and were higher for the smaller E. pacifica (15 ± 2 mm) than E. superba (48 ± 2 mm). Growth significantly lowered both Δ15Nplasma and Δ15Ncartilage, with inappetence markedly reducing Δ15Nplasma and Δ13Cplasma, as well as significantly altering blood biochemistry. Captive findings facilitated the first robust multi‐tissue growth‐ and nutrition‐corrected isotope analysis of a wild R. typus population, suggesting individual foraging specialization on low trophic level mid‐ocean or coastal prey. Long‐term fasting during ocean‐basin‐scale migrations may be common and such metabolic effects should be carefully quantified when isotopically assessing intra‐species foraging differences. The metabolically constrained multi‐tissue, multi‐isotope approach described can facilitate ecological insights that are indispensable for effective conservation and management of globally threatened, but poorly understood, species by identifying differences in key foraging areas and target prey within and between individuals.

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The first record, tagging and release of a neonatal whale shark Rhincodon typus in Taiwan

Cited by 6 publications

References 11 publications

Whale Shark (Rhincodon typus) Seasonal Occurrence, Abundance and Demographic Structure in the Mid-Equatorial Atlantic Ocean

Whale Shark (Rhincodon typus) Seasonal Occurrence, Abundance and Demographic Structure in the Mid-Equatorial Atlantic Ocean

Undersea Constellations: The Global Biology of an Endangered Marine Megavertebrate Further Informed through Citizen Science

Enhancing insights into foraging specialization in the world's largest fish using a multi‐tissue, multi‐isotope approach

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