Fig 1.
High-resolution photographs of the 13 skin mark types found in Aeolian bottlenose dolphins.
Photographs show types of marks found on different body regions (dorsal fin, flanks, tail and flukes, back etc.) or with different degree of intensity.
Table 1.
Skin marks types found in bottlenose dolphins from Aeolian Archipelago.
The scientific papers that previously described skin marks and a brief description as these appeared in photographs are reported in the second and third columns of the table. Classification of skin marks types according to the origin, time of permanence on the dolphins’ bodies and their prevalence in the population (%) are also reported in the other columns.
Fig 2.
Prevalence (%) of skin mark types for adults, juveniles and calves.
The prevalence was calculated as the number of adults, juveniles or calves with a skin mark type divided by a) the number of marked dolphins, b) the number of adults, juveniles or calves, respectively and c) the number of dolphins reporting that skin mark type. BM = Black Mark; DRL = Dark Ring Lesion; DI = Deep Indentation; GW = Gunshot Wound; IFE = Irregular dorsal Fin Edge; LW = Linear Wound; MU = Mutilation; SC = Scratch; SD = Skin Disorder; SSI = Small Shallow Indentation; TR = Tooth Rakes; WP = White Patch; WRL = White Ring Lesion.
Fig 3.
Prevalence (%) of skin mark types for males and females.
The prevalence was calculated as the number of males or females with a skin mark type divided by a) the number of marked dolphins, b) the number of males or females separately and c) the number of dolphins reporting that skin mark type. BM = Black Mark; DRL = Dark Ring Lesion; DI = Deep Indentation; GW = Gunshot Wound; IFE = Irregular dorsal Fin Edge; LW = Linear Wound; MU = Mutilation; SC = Scratch; SD = Skin Disorder; SSI = Small Shallow Indentation; TR = Tooth Rakes; WP = White Patch; WRL = White Ring Lesion.
Table 2.
Results of Kruskal-Wallis tests conducted on skin marks abundance, richness and distribution.
The analyses were carried out for dolphins grouped according to age class (adults, juveniles and calves), sex (males and females) and degree of interaction with trammel nets (DIN). Since DIN values were higher in males (DIN from 25% to 56%, with 50% of males showing a DIN > 40%) than females (DIN from 0 to 36%, with 50% of females showing a DIN > 20%), a 40% threshold was used for males and 25% for females, respectively.
Fig 4.
PCA on the severity of skin mark types.
Plots of the component scores on Factor 1 and Factor 2 according to the percentages of explained variance showing different severity for marks between a) males and females and b) dolphins with DIN more than 40% or less than 20%. Each dolphin was identified by the photo-id code (PHD), sex (m = male, f = female, u = unknown), and age class (a = adult, j = juvenile, c = calf, u = unknown). For each mark type, the loadings on Factor 1 and Factor 2 were also reported.