Human Presence on the Coast Reduces Marine Otter Abundance

ABSTRACT Anthropogenic activities can alter the occurrence of many animal species, and marine mammals, in particular, may be impacted by coastal development. The marine otter, Lontra felina , inhabits the coasts of southern South America, where increasing urban encroachment and extractive activities are progressively altering its habitat. We estimated the abundance of L. felina at six study sites (with similar habitat structure) in northern Chile over three years, relating this to the presence of people, boats, and pets. We also calculated a human disturbance index using these human presence variables. Our findings indicated that marine otter abundance was negatively associated with the number of people, while boats and pets showed no significant associations with otter abundance. The human disturbance index, which integrates these variables, was also negatively related to otter abundance. Although marine otters are generally considered tolerant to human presence in coastal environments, our results show a consistent pattern of lower otter abundance at sites with greater human presence, particularly where people directly accessed shoreline habitats. This pattern is not explained by habitat structure, which was similar across sites, and suggests that local human activity may contribute to shaping spatial variation in abundance. This multi‐year assessment raises a warning about human influence on native species in coastal areas, which can inform evidence‐based conservation decisions.