The number of stranding response facilities for marine mammals in the United States has increased over the past two decades, resulting in thousands of rehabilitated marine mammals released back into the wild (Geraci and Lounsbury 2005; Moore et al. 2007; Johnson and Mayer 2015; Simeone et al. 2015). All rehabilitated marine mammals released in the United States must be tagged or marked (50 CFR 216.27) and post-release monitoring is recommended, if not required, for some taxonomic groups. This depends on their release category as determined by a veterinarian in concordance with guidelines established by the National Marine Fisheries Service (NMFS) and the US Fish and Wildlife Service (USFWS; Whaley and Borkowski 2009). Monitoring the fate of released, rehabilitated marine mammals is not only necessary for the validation and refinement of veterinary procedures and treatments, but allows for the recovery of individuals that are unable to adapt to the wild (Whaley and Borkowski 2009). For cases in which rehabilitation is used to enhance small or endangered populations, monitoring the ability of individuals to forage, survive, and ultimately reproduce following release is essential for assessing the conservation value of a given program’s efforts. Post-release monitoring has also been useful in some cases for elucidating poorly understood ranges and habitat use of wild populations (Moore et al. 2007).