Examining Variations in Fatty Acid Profiles of The Sea Star Pycnopodia Helianthoides On the Coast of British Columbia
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Date
2022-11
Authors
Taradash, Aubrey
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Publisher
University of Oregon
Abstract
Pycnopodia helianthoides is a large, predatory sea star native to the northeast Pacific coast. This important intertidal and subtidal predator was historically abundant along the west coast of North America from Alaska to Baja California until the 2013-2015 sea star wasting epidemic caused drastic population declines throughout its range. The opportunistic diet of Pycnopodia on benthic invertebrates has previously been studied through observation, but there are no published diet analyses using fatty acids (a trophic biomarker). In order to investigate the trophic ecology of wild Pycnopodia, fatty acids were extracted and identified from tissues of 119 individuals, ranging in size from 2.6-46 cm in diameter, collected from different sites and habitats near Calvert Island, BC, Canada. The multivariate fatty acid signatures of the stars were compared between collection sites and substrate types, as well as size classes (5 categories). Fatty acids were significantly different between sites and substrates, but not size classes. These differences suggest that the diets of stars found at different sites and substrates could differ significantly, although very few sites featured more than one substrate type, making it difficult to distinguish the potential effects of each. Size class, however, does not appear to have an effect on the fatty acid compositions of the stars, indicating that Pycnopodia diets may not vary much by size, which was unexpected. Further analysis of both wild and captive stars could continue to provide more insight into the diet of this understudied species.
Description
21 pages