Seasonal contact and migration structure mass epidemics and inform outbreak preparedness in bottlenose dolphins

Infectious respiratory diseases have detrimental impacts across wildlife taxa, particularly in marine species. Despite this vulnerability, we lack information on the complex spatial and contact structures of marine populations which reduces our ability to understand disease spread and our preparedness for epidemic response. We leveraged a collated dataset to establish the first data-driven epidemiological model on a cetacean species, the Tamanends bottlenose dolphin (Tursiops erebennus), whose populations are periodically impacted by deadly respiratory disease in the northwest Atlantic. We found their spatial distribution and contact is heterogeneous along the coastline and varies by ecotype, which explains differences in infection burdens observed in past outbreaks. We also determined that outbreaks beginning in northern parts of their habitat during migratory seasons have the highest epidemic risk and that dolphins in North Carolina estuaries would be the best sentinels for disease surveillance. Our mathematical model provides a generalizable, non-invasive tool that takes advantage of routinely collected marine mammal data to mechanistically understand disease transmission and inform disease surveillance tactics for marine sentinels. Our findings highlight the heterogeneities that play a crucial role in shaping the impacts of infectious diseases in wildlife, and how a data-driven understanding of these mechanisms can enhance epidemic preparedness.