Examining the Correlation between Living and Beached Seabird Species in the San Juan Channel and Salish Sea Region.

Abstract

Alcids are some of the most common seabird species in the Salish Sea region, a sheltered pelagic ecosystem supporting various marine life. Alcids are a family of seabirds that rely solely on the water column for their nutritional needs, unlike gulls, grebes, loons, and other commonly observed marine birds that can migrate between terrestrial and oceanic ecosystems. This unique niche makes alcids a valuable indicator species for ocean health and food web disruption since they cannot exploit a broader range of food resources. This study examined the densities of live birds’ densities in the San Juan Channel, obtained from surveys between 2008 and 2023 for Common Murres, Rhinoceros Auklets, and Glaucous-winged Gulls and compared these densities to densities of beached birds. To analyze interannual variations in bird densities and the correlation between seabird population dynamics and sea surface temperature in the Salish Sea region. In most years, there is a positive correlation between the number of living and beached birds for all three species, indicating a consistent mortality rate within the populations. However, the outlier years of 2010, 2012, 2016, and 2017 appear to be related to abnormal oceanic temperatures.