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Diseases of Aquatic Organisms

    DAO prepress abstract   -  DOI:

    Pathology of short-term dorsal fin tag attachments in stranded, tagged, released and re-stranded short-beaked common dolphins (Delphinus delphis) on Cape Cod, Massachusetts, USA

    Treasa C. Deegan, Misty Niemeyer, Kathleen M. Colegrove, David S. Rotstein, Sarah M. Sharp*

    *Corresponding author:

    ABSTRACT: Odontocetes are difficult to study in the wild, making tagging and remote tracking a valuable practice. However, evaluations of host responses at tagging sites have been primarily limited to visual observations in the field. Here we explore the macro- and microscopic pathology of dorsal fin tag attachments in 13 stranded and released short-beaked common dolphins (Delphinus delphis) from Cape Cod, MA that later re-stranded and died or were euthanized 1 – 28 days post-tagging. Tags were attached to stranded dolphins’ dorsal fins using two methods: core biopsy or piercing. Grossly, the piercing method resulted in epidermal compression into the dermis. One tag site had a necrotic border 28 days after application. Grossly, the biopsy method resulted in minimal to no tissue reaction. Two tag sites had granulation tissue accumulation 4 and 12 days after tagging. Histopathologic findings for all tag types and animals consisted of focal epithelial loss, dermal edema, perivascular edema, inflammation and hyperplasia, and inter- and extracellular edema in the adjacent epidermis. Minor expected pathological changes given the procedure were also observed: superficial epidermal necrosis in three cases, and superficial bacterial colonization in two. There was no evidence of sepsis and tagging was not related to cause of re-stranding or death in any case. These gross and histopathologic findings support previous observational conclusions in small delphinids that with appropriate sterile technique, the impacts of single pin dorsal fin tagging on the animal can be minimal and localized. Of the two methods, core biopsy may be a better tagging method.