Refining instrument attachment on phocid seals

Abstract

During the 1960s through to the early 1980s, harnesses were used to attach instruments to diving marine animals such as seals and penguins. Such devices were replaced with epoxy and cyan glues and specialist adhesive tapes in the mid-1980s because of chafing and drag issues (Wilson et al. 1997, Kooyman 2007). Fedak et al. (1983) were the first to glue instruments directly to the fur of a seal. This simple, direct form of instrument attachment has become the norm in pinniped research, though details of exactly how, where, and what specific products are used vary (e.g., Fedak et al. 1983, Le Boeuf et al. 1988, Harcourt et al. 1995, Zeno et al. 2008). The attachment of tracking and bio-logging devices has been identified as a particular animal welfare concern (Hawkins 2004), the main concern being that these attachments may cause physical pain and suffering with subsequent changes in behavior or survival. Two recent studies (McMahon et al. 2008, Mazzaro and Dunn 2009) have specifically assessed the impacts of attaching tracking instruments to seals. McMahon et al. (2008) clearly demonstrated that for southern elephant seals (Mirounga leonina), carrying tracking devices produced no detectable differences in overwinter mass gain nor in long-term survival. In a study conducted with two captive harbor seals (Phoca vitulina), Mazzaro and Dunn (2009) noted no tagassociated changes in health or behavior until one tag started to loosen a few days before detachment, at which time a small area became irritated when the epoxy cracked and began rubbing against the seal. However, there have been no studies of potential injuries that might lead to pain as a result of instrument attachment on wild seals. This is primarily because of the difficulty in monitoring instrumented marine mammals following their release. Here we (1) present information on the performance of three different, widely used, epoxies to determine whether any of them might cause burns via exothermic chemical reactions when the glue cures under common fieldwork conditions in subantarctic and polar deployments; and (2) review injury rates for 454 southern elephant seals and 54 Weddell seals (Leptonychotes weddellii) that have been resighted after instruments have been deployed.