Relationship between whale melanin abundance and skin lesions: (A) intracellular oedema (n = 39 and n = 66 for absence and presence, respectively) (B) cytoplasmic vacuolation (n = 9, n = 23, n = 41, n = 35 for vacuolation levels of 0, 1, 2 and 3, respectively; see8), and (C) blue whale mitochondrial DNA lesions. (D) Inverse correlation between mitochondrial DNA (mtDNA) lesion density and HSP70 expression levels (ΔCt). (E) Direct correlation between mtDNA lesion density and individual minimum age of blue whales (calculated by taking into account the first year of observation reported for a particular individual in the Gulf of California; individuals with a minimum age of 1 were excluded; individuals that were observed in the Gulf of California on the year they were born, and as such their exact age was known, were included). Bars = ± 95% CI.