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First report of a sleeper shark (Somniosus sp.) in the western Caribbean, off the insular slope of a coral atoll

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A sleeper shark (Somniosus sp.) was captured over the insular slope at Glover’s Reef, a coral atoll in Belize. The estimated total length of the individual was ca. 3.0–3.5 m and multiple morphological features diagnostic of a somniosid shark (short snout, presence of an ectoparasitic copepod on the eye, low and rounded dorsal and pectoral fins, and small eyes with posteriorly situated large spiracles) were observed. While the exact species could not be confirmed, it is most likely a Greenland shark (Somniosus microcephalus) or a hybrid between the Greenland shark and the Pacific sleeper shark (Somniosus pacificus). This is the first record of a sleeper shark in the western Caribbean region and further supports the hypothesis that these sharks, best known from polar and subpolar latitudes, occur at depth in tropical regions.

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Data availability

Data supporting the findings of this expedition are available as supplementary material and are publicly available.


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We thank the Belize Department of Fisheries for permitting this research. This expedition was funded by grants from The Ellen Fund, Georgia Aquarium and the Roe Foundation to D.D.C. We thank Dr. R. Dean Grubbs at Florida State University, Dr. M. Aaron MacNeil at Dalhousie University and Dr. Nigel E. Hussey at the University of Windsor for additional confirmation of shark ID. We thank Shashank Srinivasan at Technology for Wildlife Foundation for cartography.


This expedition was funded by The Ellen Fund, Georgia Aquarium and the Roe Foundation.

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Authors and Affiliations



DK wrote the manuscript with input from DDC. DK, HDM, OF, NM and EG conducted the field operations and made observations. DDC obtained project funding.

Corresponding author

Correspondence to Devanshi Kasana.

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The authors declare no conflict of interest.

Ethical approval

All research fishing activities were conducted under Belize Fisheries Department Permit #0006-22 and approved animal care protocol #IACUC-20-017-CR02.

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Responsible Editor: John K. Carlson.

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Kasana, D., Martinez, H.D., Faux, O. et al. First report of a sleeper shark (Somniosus sp.) in the western Caribbean, off the insular slope of a coral atoll. Mar Biol 169, 101 (2022).

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