Quantifying southern sea otter (Enhydra lutris nereis) reactions to a quadcopter drone in central California

Marine Mammal Science
By: , and 

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Abstract

Drones are useful for wildlife research and management, but they can cause disturbance and harassment to wildlife. Sea otters (Enhydra lutris) are candidates for drone-based observation and monitoring but are vulnerable to disturbance. No studies have evaluated drone effects on sea otter behavior, but based on prior disturbance studies, we hypothesized: (1) sea otters would exhibit behaviors indicating higher reactivity in the presence of drones than when drones were absent and (2) drone disturbance to sea otters would be greater when drones were closer. At two sites in Monterey Bay, CA, we conducted 37 observational sessions, recording behavior codes for focal sea otters during a baseline (no drone) period and three consecutive drone flights. Data were analyzed using ANOVA and ordinal logistic regression models. At both locations, focal sea otters had higher behavior codes during drone trials compared to baseline, and behavior codes increased with descending drone altitude. Pup presence, group size, flight trial number, and gull presence were significant covariables. We calculated multipliers to predict drone-mediated behavioral responses at a range of drone altitudes. Our findings can inform best practices for a variety of uses of drones around sea otters, including population monitoring, oil spill response, and drone photography/videography.

Suggested Citation

Young, C., Yee, J.L., Bentall, G., Staedler, M.M., Carswell, L., and Daly, M., 2026, Quantifying southern sea otter (Enhydra lutris nereis) reactions to a quadcopter drone in central California: Marine Mammal Science, v. 42, no. 3, e70185, 13 p., https://doi.org/10.1111/mms.70185.

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Publication type Article
Publication Subtype Journal Article
Title Quantifying southern sea otter (Enhydra lutris nereis) reactions to a quadcopter drone in central California
Series title Marine Mammal Science
DOI 10.1111/mms.70185
Volume 42
Issue 3
Publication Date May 15, 2026
Year Published 2026
Language English
Publisher Wiley
Contributing office(s) Western Ecological Research Center
Description e70185, 13 p.
Country United States
State California
Other Geospatial Cannery Row, Monterey Bay, Otter Point
Additional publication details