A WSG-funded project informs future restoration efforts and resilience for pinto abalone populations in the Pacific Northwest.
June 9, 2025
Adult pinto abalone outplanted on rock. Photo credit: Taylor Frierson
Seattle, WA – You may know abalone by its shimmery shell, but the pinto abalone, Washington’s only native abalone species, is now better known for its sharp decline. Between 1992 and 2017, pinto abalone populations in Washington plummeted by 97%. Despite over a decade of restoration efforts, recovery has been slow—and new research suggests climate change may further threaten this iconic marine mollusc.
A new paper released in Scientific Reports, a journal published by Nature Portfolio, found climate change stressors (ocean warming and ocean acidification) negatively impact pinto abalone during their larval stage. Funded by Washington Sea Grant, the study was led by recently-graduated doctoral student Eileen Bates and principal investigator Jacqueline Padilla-Gamiño at the University of Washington’s School of Aquatic and Fishery Sciences, in collaboration with the Puget Sound Restoration Fund and the Washington Department of Fish and Wildlife.
The researchers examined larval survival, settlement success (transition from larvae to juvenile stage), and shell growth under various combinations of temperature and pH stress. They found that the combination of high temperature and low pH had the most pronounced negative effect, disrupting early development and increasing mortality.
Pinto abalone are key players in coastal ecosystems. As grazers, they control algae growth, helping to maintain the structure and balance of marine habitats. They also hold deep cultural significance for indigenous communities in the Pacific Northwest, who have long relied on them for food and tradition.
Eileen Bates installing sensors to monitor oceanographic conditions, surrounded by crustose coralline algae. Photo credit: Katie Sowul
Despite the fishery closure in 1994 and the species’ listing as endangered in Washington state in 2019, wild populations have not rebounded. A major challenge has been the lack of data on optimal rearing conditions and environmental stressors affecting juvenile survival after release. This new research provides critical insight into how climate change will shape the future of pinto abalone recovery. “Our results show that early life stages of pinto abalone are especially vulnerable to the effects of climate change, which has major implications for restoration. By understanding how temperature and ocean acidification impact survival and development, we can help managers refine hatchery practices and choose restoration sites that give these animals the best chance to thrive,” explains Dr. Padilla-Gamiño.
Restoration practitioners, including the Puget Sound Restoration Fund (PSRF), can use the findings to refine hatchery and out-planting methods in the Strait of Juan de Fuca and across the broader Pacific Northwest. Bates currently works with PSRF to improve pinto abalone rearing and restoration efforts given the threats of climate change. “This research set us up for several follow up experiments and studies in both the hatchery and the field that are helping us better understand where and how pinto abalone might be able to thrive in the future,” comments Bates.
Beyond climate impacts, the researchers are also investigating how probiotics, tank microbiomes, substrate type, and oceanographic conditions influence abalone health and survival—highlighting the importance of strong partnerships between scientists and state agencies in restoring and protecting this culturally and ecologically vital species.
To read more about the project, visit: wsg.washington.edu/unblocking-bottlenecks-in-recovery-of-endangered-pinto-abalone-populations/
CONTACTS:
Eileen Bates, eileen@restorationfund.org
Written by Luciana Calle, WSG Science Communications Fellow
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Washington Sea Grant, based at the University of Washington, helps people and marine life thrive through research, technical expertise and education supporting the responsible use and conservation of coastal ecosystems. Washington Sea Grant is one of 34 Sea Grant programs supported by the National Oceanic and Atmospheric Administration in coastal and Great Lakes states that encourage the wise stewardship of our marine resources through research, education, outreach and technology transfer.
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JUN
2025