Breaking down “harassment” to characterize trends in human interaction cases in Maine's pinnipeds

Abstract

Recent marine mammal recovery and growth of human populations in coastal areas has led to increased human harassment of protected pinniped populations. Yet, current monitoring approaches lack the necessary resolution to describe this emerging issue. We therefore propose a new classification scheme for monitoring of marine mammal–human interaction (HI), which defines categories based on the type of human behavior and associated risks to the animal. Among harbor, harp, and gray seal strandings (N = 3,525) from 2007 to 2019 in Maine, United States, evidence of HI was reported in 14.72% of strandings, with the majority (75.34%) of these cases involving harassment. The number of HI reports increased over time, particularly in the southern region of the state, and an analysis of geographic hotspots further identifies emerging areas of concern. Variation in the rate and type of HI among species, age classes, and seasons reflect differences in pinniped life history. The most commonly observed types of harassment included human approach, physical contact, and displacement. By breaking down harassment, we aim to inform ongoing mitigation efforts and contribute to our understanding of the impact of HI on marine mammal health, as well as offer a transferable methodological approach to monitoring human–wildlife interaction.