Landscape scale thermoregulatory costs from sublethal exposure to Deep Water Horizon oil in the double-crested cormorant

• Published in: Marine pollution bulletin 2020-03, Vol.152, p.110915-110915, Article 110915
• Main Authors: Dorr, Brian S., Mathewson, Paul D., Hanson-Dorr, Katie C., Healy, Katherine A., Horak, Katherine E., Porter, Warren
• Format: Article
• Language: English
• Subjects: Bioenergetics modeling; Bird populations; Birds; Breeding seasons; Deep water; Exposure; Foraging; Niche mapper; Niches; Oil spills; Oil toxicity; Seabirds; Thermoregulation; Toxicity; Water pollution effects; Wildlife
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2020.110915

Toxic effects of heavy oiling to wildlife are well known from oil spills, although sublethal oil exposure effects are poorly understood. We used Niche Mapper™, to compute spatially and temporally specific energetic and behavioral impacts of repeated sublethal oil exposure to double-crested cormorants (Phalacrocorax auritus). During winter (October–March) cormorants exposed to 13 g, 39 g, and 65–78 g of oil, had on average a 31%, 59%, and 76% predicted increase in total resting energetic requirements (RMR) compared to unoiled birds, respectively. Increased RMR resulted in a mean (±SD) predicted increase in time spent foraging of 36 (±13) min·d−1. During the breeding season (April–September), cormorants had on average a 29%, 57% and 73% increase in total RMR and the mean predicted increase in time spent foraging was 131 (±49) min·d−1. Thermoregulatory effects of sublethal oil exposure may cause greater impacts to bird populations than is currently understood. •Modeled spatially and temporally specific energetic effects of sublethal oil exposure for a bird•Increase in thermoregulatory costs of up to 165% of resting metabolic rate•Increases in thermoregulatory cost could increase foraging related activities up to 6.3 h/d.•Sublethal oil exposure may cause greater impacts to birds than previously considered.