Stranded whale shark (Rhincodon typus) reveals vulnerability of filter-feeding elasmobranchs to marine litter in the Philippines

Abreo, Neil Angelo S.; Blatchley, Darrell D.; Superio, Michael Dann

doi:10.1016/j.marpolbul.2019.02.030

Cited by 34 publications

(21 citation statements)

References 16 publications

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“…However, to our knowledge, no plastic abundance estimates for manta ray and whale shark feeding grounds currently exist for Indonesia or the greater Coral Triangle. Furthermore, while there is empirical evidence that whale sharks ingest plastic (Haetrakul et al, 2009;Sampaio et al, 2018;Abreo et al, 2019;Donati et al, 2019), confirmation that manta rays ingest plastics is yet unavailable. Plastic ingestion by manta rays might be confirmed from opportunistic stomach contents analysis of stranded individuals (e.g., Haetrakul et al, 2009;Besseling et al, 2015;Sampaio et al, 2018;Abreo et al, 2019) and could potentially also be assessed through non-invasive analysis of egested material (Donati et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Microplastics on the Menu: Plastics Pollute Indonesian Manta Ray and Whale Shark Feeding Grounds

et al. 2019

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Microplastics in Indonesian Megafauna Habitats ray egested material confirmed plastic ingestion, the consequences of which might include exposure to toxic plastic additives and adhered persistent organic pollutants. Communicating this information to communities who stand to benefit from healthy megafauna populations might help local governments as they work toward reducing plastics in the marine environment.

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Section: Introductionmentioning

confidence: 99%

Microplastics on the Menu: Plastics Pollute Indonesian Manta Ray and Whale Shark Feeding Grounds

et al. 2019

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“…Moreover, it is unclear whether all macro- and microplastics are egested. Even though our opportunistic sampling did not allow to consider macroplastics, previous stomach content analyses from stranded individuals highlighted, that whale sharks ingest macroplastics, such as drinking straws and sheet-like items [ 16 , 17 , 19 ]. While Abreo et al [ 16 ] did not find any indication of potential problems caused by the ingested plastics, Haetrakul et al [ 17 ] reported stomach lacerations, and Matsumoto et al [ 19 ] linked a macroplastic to the obstruction of pylorus and eventual death of that whale shark.…”

Section: Discussionmentioning

confidence: 99%

“…Whale sharks thus not only ingest microplastics directly from the water, but further uptake could occur via trophic transfer [ 15 ]. Opportunistic sampling of stranded whale sharks has confirmed that indeed larger plastic items are ingested [ 16 – 19 ], but to date, evidence of direct microplastic ingestion is lacking.…”

Section: Introductionmentioning

confidence: 99%

Microplastics in fecal samples of whale sharks (Rhincodon typus) and from surface water in the Philippines

et al. 2021

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Marine plastic abundance has increased over the past 60 years and microplastics (< 5 mm) constitute a primary component of such litter. Filter-feeding megafauna, such as the whale shark, might be particularly affected by microplastic pollution as their feeding mode requires filtration of up to thousands of cubic meters of water. In addition, the habitat range of whale sharks intersects with several recognized microplastic pollution hotspots, among which is the Coral Triangle. Direct evidence for microplastic ingestion in whale sharks however, has not yet been presented. Here we show that whale shark scat collected in the Philippines from 2012 to 2019 contained a mean of 2.8 microplastics g− 1. Contrary to our expectations, the microplastic concentration in the scat remained consistent from 2012 to 2019. Water samples from the study site in 2019 indicated that the local microplastic pollution (5.83 particles m− 3) was higher than in surface waters in other whale shark habitats, but well below other pollution hot-spots found in Southeast Asia and China (range: 100–4100 particles m− 3). With the predicted growth in plastic use, leading to increased plastic marine pollution, whale sharks are expected to become more exposed to this form of pollution. To what extent microplastic ingestion impacts the overall health status of this endangered species remains an open question.

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“…Borucinska, Harshbarger, & Bogicevic, 2003; Borucinska, Kohler, Natanson, & Skomal, 2002; Borucinska, Martin, & Skomal, 2001; Orós, Torrent, Calabuig, & Déniz, 2005). Other foreign bodies reported include stones (Blue & Wittkopp, 1981), ropes and fishing gaffs (Otway, 2015), fishing lines (Franchini et al., 2018) and more recently plastics (Abreo, Blatchley, & Superio, 2019; Gall & Thompson, 2015). In sharks, foreign bodies, especially hooks, can lead to underlying chronic disease and cachexia (e.g.…”

Section: Introductionmentioning

confidence: 99%

Hook‐shaped enterolith and secondary cachexia in a free‐living grey nurse shark (Carcharias taurus, Rafinesque 1810)

Otway

West

Gore

et al. 2020

Veterinary Medicine & Sci

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The carcass of a critically endangered, juvenile female grey nurse shark (Carcharias taurus, Rafinesque 1810) was recovered from a south‐eastern Australian beach and subjected to necropsy. The 1.98‐m‐long shark exhibited advanced cachexia with its total weight (19.0 kg) and liver weight (0.37 kg) reduced by 60% and 89%, respectively, compared with a healthy individual of the same length. Marked tissue decomposition was evident preventing histopathology and identification of a definitive cause of death. At necropsy, the abdominal organs were abnormally displaced and showed marked reductions in size compared with a healthy individual of the same size. Importantly, a hook‐shaped enterolith (HSE), with a rough surface and cream in colour, was found within the spiral valve of the intestine and is to the authors’ knowledge, the first description of such in any marine animal. X‐ray diffractometry showed that the HSE comprised the minerals monohydrocalcite (Ca[CO₃].H₂O; ~70 wt%) and struvite (Mg [NH4] [PO4]. [H2O]6; ~30 wt%). A CT scan showed concentric lamellate concretions around a 7/o offset J‐hook that formed the nidus of the HSE. Nylon fishing line attached to the hook exited the HSE and was evident in the abdominal cavity through a perforation in the intestinal wall where the posterior intestinal artery merges. The most parsimonious reconstruction of events leading to enterolithiasis and secondary cachexia in this shark was the consumption of a hooked fish and subsequent hook migration causing perforations of the cardiac stomach wall followed by the thin, muscular wall of the apposed, sub‐adjacent intestine.

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Stranded whale shark (Rhincodon typus) reveals vulnerability of filter-feeding elasmobranchs to marine litter in the Philippines

Cited by 34 publications

References 16 publications

Microplastics on the Menu: Plastics Pollute Indonesian Manta Ray and Whale Shark Feeding Grounds

Microplastics on the Menu: Plastics Pollute Indonesian Manta Ray and Whale Shark Feeding Grounds

Microplastics in fecal samples of whale sharks (Rhincodon typus) and from surface water in the Philippines

Hook‐shaped enterolith and secondary cachexia in a free‐living grey nurse shark (Carcharias taurus, Rafinesque 1810)

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