Rare sighting of an anomalously white harbour porpoise (Phocoena phocoena) in the Moray Firth, north-east Scotland

Abstract

This paper describes a rare sighting of an anomalously white harbour porpoise (Phocoena phocoena) in the coastal waters of the outer Moray Firth in northeast Scotland. The recording provides the first photographs of such an individual from the northern North Sea. At an estimated body length of 1.5 m, the present animal had evidently survived to adulthood, in spite of its condition, confirming the potential longevity of such hypo-pigmented individuals in the wild. Further recaptures of this naturally-marked animal may provide valuable information on the site fidelity and long-term spatial movements of these notoriously difficult to study cetaceans.

A Scientometric Review on Leucism in Wild Dolphins

“…However, both juvenile and adults were reported in the 14 articles investigated herein. This corroborates several previous assessments in marine mammals, indicating evident survival and relative longevity of leucistic individuals (Forestell et al, 2001;Tonay et al, 2012;Robinson & Haskins, 2013;Gil et al, 2019), both male and females, in line with studies indicating no associations to negative consequences in a specific habitat for several species (Abreu et al, 2013;Kopaliani et al, 2017). For example, Antarctic fur seals (Arctocephalus gazella) from Bird Island, South Georgia, displaying hypopigmentation attributed to leucism were identified as homozygous for a nonsynonymous mutation within the MC1R gene.This results in the substitution of serine with phenylalanine at an evolutionarily highly conserved structural domain.…”

“…Several negative leucism effects have been postulated, such as reduced countershading, in turn increasing detection by predators or prey species and prey avoidance (Sandoval-Castillo, Mariano-Meléndez & Villavicencio-Garayzar, 2006;Acevedo, Aguayo-Lobo & Torres, 2009); increased chances of sunburn or skin cancer; reduced heat absorption, leading to thermoregulatory limitations in cold waters, reduced attractiveness to the opposite sex, leading to decreased mating success, or inbreeding, since some assessments in mammals have reported a possible link between coloration and inbreeding, where affected individuals could be at a fitness disadvantage due to inbreeding depression (Fertl & Rosel, 2009;Keener et al, 2011;Prado-Martinez et al, 2013;Robinson & Haskins, 2013;Peters et al, 2016).…”

“…It has been hypothesized that hypopigmentation may result in several negative effects, such as higher predation rates (Sandoval-Castillo et al, 2006;Acevedo, Aguayo-Lobo & Torres, 2009); increased sun sensitivity; reduced heat absorption, decreased mating success or inbreeding (Fertl & Rosel, 2009;Keener et al, 2011;Prado-Martinez et al, 2013;Robinson & Haskins, 2013;Peters et al, 2016). However, other studies have indicated that a higher than normal frequency of unusually colored individuals is not associated to negative consequences in a specific habitat (Kopaliani, Gurielidze & Ninua, 2017;Sokos et al, 2018).…”

Records of harbour porpoise (Phocoena phocoena) in the mouth of the Douro River (northern Portugal) with presence of an anomalous white individual

“…Albino cetaceans are characterized by the total absence of melanin. Therefore, this white individual is better characterized as leucistic or hypo-pigmented (Robinson and Haskins 2013;Tonay et al 2012).…”

“…Although little is known about the leucistic condition, the fact is that the brighter colour makes the individuals more susceptible to predators. The lack of melanin in the skin increases the probability of sunburns and skin cancer and the reduced heat absorption possibly gives lower thermoregulatory capacities in cold waters (Robinson and Haskins 2013). The reported presence of these porpoises and the leucistic individual for at least 3 years, indicates that some of the observed animals are probably adults, surviving in the area despite the anthropogenic impacts.…”