Coastal observations of seabird mortality in Katmai National Park, Alaska: 2012?2021

Abstract

In 2012, Katmai National Park & Preserve joined the stranded seabird survey efforts spearheaded by the University of Washington?s Coastal Observation and Seabird Survey Team (COASST). COASST is a citizen science network started in 1999 with the goal of establishing a baseline dataset of seabird mortality to identify unusual die-offs. During the winter of 2015 and spring of 2016, the Gulf of Alaska experienced a large die-off of common murres (Uria aalge; COMU) due to a severe marine heatwave in the North Pacific. Katmai National Park & Preserve (KATM) staff contributed to the identification and documentation of seabird carcasses washed ashore from this die-off; in 2016 alone, 90 murres (likely COMU; only counting new birds) were documented along a 1 km stretch of Swikshak beach. KATM staff have conducted a total of 105 COASST surveys documenting 203 seabird carcasses on four 1 km section of beaches in KATM and Bristol Bay: Swikshak, Hallo, North Hallo, and Naknek. During the peak of the die-off in 2016, Swikshak beach contained an average of 20.6 carcasses per survey. During a typical year (using 2014 as an example), the average was 0.33 carcasses, highlighting the severe impact that die-off events like this have on seabird colonies. These events have occurred throughout Alaska annually since 2015 (USFWS 2021) and have affected some of our beaches every year, particularly Naknek Beach in 2019.