Unusual occurrence of abnormal skin pigmentation in blacktip reef sharks (Carcharhinus melanopterus)
Total albinism has been reported in 26 shark species, including a single report in a blacktip reef shark (Carcharhinus melanopterus) from India (Manojkumar 2011). In Baa Atoll, Maldives, we identified eight young of the year (YOY; 40–60 cm) C. melanopterus with abnormal skin pigmentation that resembles leucism. Leucism, a genetic disorder reported in mammals, reptiles, amphibians, teleosts, and more recently elasmobranchs, is associated with abnormal skin pigmentation caused by a prenatal enzyme deficiency involved in the metabolism of melanin. This rare condition differs from true albinism as it is characterized by a reduction in melanin over the entire or part of the body, while affected animals have normal eye color (Lutz 2001).
Atypical pigmentation in animals has been related to genetic alterations in melanin production, inbreeding within isolated populations, environmental stress associated with areas of high human activity, and exposure to elevated temperatures (Gervais et al. 2016). In the Maldives, this condition may be associated with heavy fishing pressure prior to 2010, the current development boom, extensive land reclamation and burial of reefs to create artificial islands, or abnormally high sea water temperatures during the 2015–2016 El Niño. The abnormal pigmentation on sharks places them at greater risk of predation.
This research was partially funded by the Greenville Zoo Conservation Fund.
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Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
- Manojkumar PP (2011) First record of albinism in the blacktip reef shark Carcharhinus melanopterus from Malabar Coast. Mar Fish Inf Ser T & E Ser 208:36Google Scholar