Category: Status Reports
Published: April 2019
Author(s): Henry S. Carson and Michael Ulrich
The pinto abalone (Haliotis kamtschatkana) is a shallow-water marine mollusk native to the marine waters of Washington State, particularly the San Juan Islands and Strait of Juan de Fuca. It is a grazer, feeding on diatoms and kelp, living on bedrock or boulder reefs. Juveniles are cryptic but emerge as adults around the reproductive size of 40 – 70 mm shell length. Males and females spawn gametes directly into the water in spring and summer; fertilization occurs outside the body. After a relatively short drifting larval phase of 7 – 10 days, abalone settle into appropriate habitat, often bull kelp beds and on rock covered in crustose coralline algae.
Likely harvested for subsistence by early inhabitants of the Pacific Northwest for centuries, the Department authorized the state recreational harvest of abalone in 1959. In 1992, managers grew concerned about observed abundance trends and established ten fixed monitoring sites in the San Juan Islands. Upon a resurvey of those stations in 1994 that showed a decline in abundance, and evidence of significant illegal harvest, managers closed the fishery. The population on these sites continued to decline despite the fishery closure. The most recent survey in 2017 found 12 total abalone remaining from an original tally of 359 in 1992 – a 97% decline. Furthermore, the average size of abalone has increased over time, and juveniles have not been sighted during Department surveys since 2008.
Available evidence suggests that the Washington population is aging and has experienced widespread reproductive failure. Since the animals spawn directly into the water, males and females must be in close proximity for fertilization to occur. Adults maintain a small home range and may not migrate long distances to spawn with other individuals. Therefore, when legal or illegal fishing reduces the density of adults below some fertilization threshold, successful reproduction is reduced and remnant populations are unlikely to recover naturally. In addition to a low density of adults, pinto abalone populations in Washington face threats from changing ocean conditions, illegal harvest, reduced genetic diversity, disease, contaminants, and native or introduced predators.
A captive breeding and reintroduction partnership was formed between the Department, Puget Sound Restoration Fund, the National Oceanic and Atmospheric Administration, treaty tribes, universities and others. Since 2009 the partnership has outplanted groups of hatchery-origin juveniles onto sites in the San Juan Islands. The growth and survival of these individuals suggests that this restoration strategy is a viable one. However, pinto abalone would have to be produced and outplanted in significantly greater numbers to achieve population-scale recovery.
Due to the dwindling numbers of wild individuals, their apparent lack of natural reproduction, and a number of identified threats, it is recommended that the pinto abalone be listed as endangered in the state of Washington.
Carson, H.S. and Ulrich, M. (2019) Status report for the pinto abalone in Washington. Washington Department of Fish and Wildlife, Olympia, Washington. iii + 25 pp.
Draft documents are provided for informational purposes only. Drafts may contain factual inaccuracies and may not reflect current WDFW policy.