This paper discusses that appearance of pyrosomes (P. atlanticum) in coastal waters near northern California, Oregon, and Washington north of their previously reported range since 2014. By the summer of 2017, pyrosomes appeared in unprecedented numbers along the entire west coast, reaching the Western Gulf of Alaska, but showed some of their highest abundances off Oregon clogging nets and disrupting marine activities such as commercial and sport fisheries.
The impacts of these dense blooms and the extent on ecological interactions are unknown. Moreover, their appearance in multiple years and the capacity to reach bloom proportions suggests that pyrosomes may even thrive in colder waters, especially during more oligotrophic conditions, and could become more permanent residents in the California Current marine ecosystem. Their continued presence will likely become a nuisance for certain fishing activities, causing fishermen to relocate or spend extra time sorting their catch. Large pyrosome aggregations have the potential to restructure energy flows through food webs via efficient removal of photosynthetic plankton and subsequent fecal pellet production, consumption by higher trophic levels, or sinking to depth.