Prevalence of skin lesions in common bottlenose dolphins (Tursiops truncatus (Montagu, 1821)) in the Central Adriatic Sea

master's thesis

• Title (croatian): Učestalost kožnih lezija kod dobrog dupina (Tursiops truncatus (Montagu, 1821)) u srednjem Jadranu
• Author: Korina Ujčić
• Mentor: Draško Holcer (mentor)
• Mentor: Zoran Marčić (sumentor)
• Committee member: Zoran Marčić (predsjednik povjerenstva)
• Committee member: Petar Žutinić (član povjerenstva)
• Committee member: Duje Lisičić (član povjerenstva)
• Committee member: Petar Kružić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2021-07-19, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Photo-identification data of 35 common bottlenose dolphins (Tursiops truncatus, Montagu 1821) encountered in Vis archipelago from 2014 until 2018 were acquired from the Blue World Institute database to investigate the prevalence of skin lesions. According to their appearance and descriptions from available literature, 21 predefined lesion categories were used. The prevalence of lesions over time and the body areas affected were studied to assess their extent, progression, and duration. Association between lesion categories was investigated, as well as the viability of using lesions on the dorsal fin as a proxy for assessing the prevalence of lesions on other parts of the body. Lesions were found in 29 (82.86%) of the studied individuals and 15 lesion categories were recorded, of which the most common were pale skin patches, dark-fringed spots, rake mark associated, and tattoo-like lesions. No significant associations were found between the lesion categories. More lesions were recorded on the sides of the body than on the dorsal parts, and the results implied that the dorsal fin is not a reliable proxy for lesion prevalence. Of 205 lesion occasions recorded, 49 (23.9%) retreated. The observed longevity of lesions varied. Progression was observed for tattoo-like and pale lesions, and dark-fringed spots.

Abstract (croatian)

Podaci prikupljeni metodom foto-identifikacije za 35 jedinki običnog dobrog dupina (Tursiops truncatus, Montagu 1821) opaženih na području Viškog arhipelaga od 2014. do 2018. preuzeti su iz baze podataka Instituta Plavi svijet s ciljem istraživanja učestalosti kožnih lezija. Prema vidljivim obilježjima i opisima iz literature, unaprijed je definirana 21 kategorija lezija. Istraženi su učestalost i položaj lezija kroz vrijeme kako bi se dobio uvid u njihov obim, promjene kroz vrijeme i trajnost. Ispitano je postoje li veze između kategorija te mogu li lezije zabilježene na leđnoj peraji biti dovoljne za procjenu učestalosti lezija na ostalim dijelovima tijela. Lezije su zabilježene kod 29 (82,86%) jedinki i zabilježeno je 15 kategorija, od kojih su najučestalije bile blijede fleke, fleke s tamnim prstenom, lezije na tragovima nastalim grebanjem zubima i „tetovaže“. Nisu pronađene značajne veze među kategorijama. Veća učestalost lezija zabilježena je na lateralnim nego na dorzalnim dijelovima tijela. Rezultati su pokazali da leđna peraja nije dobar pokazatelj učestalosti lezija. Od 205 zabilježenih slučajeva lezija, 49 (23,9%) se s svremenom povuklo. Zabilježena trajnost lezija je varirala. Ulegnuća, ožiljci, bijele fleke i fleke omeđene bijelim prstenom su zabilježene kroz najdulji period. Promjene u izgledu zabilježene su kod „tetovaža“, fleka s tamnim prstenom i blijedih lezija.

• Keywords: photo-identification; epidermal conditions; visible features; lesion longevity; Vis archipelago
• Keywords (croatian): foto-identifikacija; kožne promjene; vidljive karakteristike; trajnost lezija; Viški arhipelag
• Language: croatian
• URN:NBN: urn:nbn:hr:217:047710
• Study programme: Title: Ecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra ekologije i zaštite prirode (magistar/magistra ekologije i zaštite prirode)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2023-07-19
• Created on: 2021-07-22 12:45:35