Viability of Photo-Identification as a Tool to Examine the Prevalence of Lesions on Free-Ranging Common Dolphins (Delphinus sp.)

Abstract

Lesions on cetacea can be useful to assess the nat-A variety of dermal lesions have been observed ural and anthropogenic pressures faced by a popu-on live, stranded, and bycaught cetaceans worldlation. The aim of this study was to assess the via-wide. Such lesions have been described as hyperbility of photo-identification (photo-ID) as a tool pigmented (

Skin marks in bottlenose dolphins (Tursiops truncatus) interacting with artisanal fishery in the central Mediterranean Sea

“…), rubbing with inanimate objects, fishing gears or rocky sea bottom or interacting with other species, such as fish and molluscs [7, 44, 69, 71], they may indicate a significant condition of distress for the Mediterranean cetaceans, but, as these marks have relatively short permanence time [7, 19, 29, 32, 35, 63, 72], they rarely pose a threat to the dolphins’ health and survival. In contrast, permanent marks have been associated to deep injuries from various sources [10, 16, 28–32, 36, 62, 68, 70, 79–81] and with different degree of severity [21, 22, 26, 32, 63]. In particular, permanent marks may lead to serious difficulties in physiological and behavioural patterns and, in some cases, to the death of the individual [66, 82].…”

“…In particular, permanent marks may lead to serious difficulties in physiological and behavioural patterns and, in some cases, to the death of the individual [66, 82]. For example, dolphins entangled in driftnets may be affected by injuries produced by fishermen, such as deep indentations or mutilations of stuck appendices [13, 29, 32, 62, 70], which might lead to dangerous infections and could limit swimming activities, inducing to a higher energy demand, starvation and consequent death. Mutilations, in our population, were reported in the dorsal fin and tail of 2 adult males with lethal consequences in one of them.…”

“…However, it is possible that the overfishing practices performed in bottlenose dolphins foraging areas might reduce the distribution of food resources, increasing the costs of feeding competition and affecting the animals’ health [37]. Other marks, such as irregular dorsal fin edge and deep indentations, might be due to a combination of behavioural and anthropogenic effects [62, 70, 71]. For example, skin disorder was very common in Aeolian bottlenose dolphins (70%) as well as small shallow indentations (84%), both resulting from social interactions and anthropogenic factors together [35–38, 60, 76, 79].…”

Skin lesion prevalence of estuarine common bottlenose dolphins (Tursiops truncatus) in North Carolina, with comparisons to other east coast study sites

“…The number of lesions per individual was classified as singular or multiple. Lesion type was categorized based on macroscopic features, including form, shape, and color and descriptions from previous studies (Hart et al, 2012; Hupman et al, 2017; Sanino et al, 2014; Van Bressem et al, 2007, 2015; Wilson et al, 1997). These categories included: (1) black, (2) pale, (3) dark‐fringed, (4) spotted, (5) vesicular, or (6) white‐fringed.…”

“…Skin lesions have been observed among various species of cetaceans throughout the world (Bearzi et al, 2009; Bertulli et al, 2012; Hamilton & Marx, 2005; Hart et al, 2012; Hupman et al, 2017; Kiszka, Van Bressem & Pusineri et al, 2009; Martinez‐Levasseur et al, 2011; Thompson & Hammond, 1992; Van Bressem et al, 2003b, 2015). Lesions may have a bacterial, viral, or fungal origin (Hart et al, 2012; Reif et al, 2008; Van Bressem et al, 1999).…”