Sea cucumbers show signs of rebounding

The sea cucumber population is potentially rebounding in the San Juan Islands, thanks to incremental harvest rate reductions and spawning closures since the 2014 fishing season.

The management strategy was implemented by the treaty tribes and the Washington Department of Fish and Wildlife following a two-year study conducted by Karl Mueller, a shellfish biologist in the Lummi Nation Natural Resources Department, and a review of the status of the state fishery by Washington Department of Fish and Wildlife (WDFW).  

Sea cucumbers have been harvested from shallow marine waters across the Pacific Ocean for centuries. Lummi speakers know the sea cucumber as ts’ikt, whereas Lushootseed speakers know it as təǰabac. It is high in protein and low in fat. Its flavor has been described as an earthy mixture of fish and shrimp. 

Mueller weighs a sea cucumber during a fall 2021 stock assessment in the San Juan Islands, done in partnership with the Swinomish Indian Tribal Community’s Fisheries Department.

A nontribal commercial sea cucumber fishery on the U.S. west coast began in the 1970s and, according to Mueller’s report, was only “passively managed” at the time (treaty tribes of western Washington were not yet engaged in commercial sea cucumber harvest). The nontribal sea cucumber harvest peaked in 1990 at more than 4 million pounds. 

Treaty tribes in western Washington resumed exercising their right to harvest sea cucumbers in the mid-1990s after the Rafeedie decision, the federal court ruling that reaffirmed the tribes’ treaty rights to share shellfish harvests equally with the nontribal citizenry of the state. Sea cucumbers harvested by tribal members are predominantly exported to Asia, where they are a delicacy.

Noting that the sea cucumber population was not rebounding from the passively managed harvest of the 1970s-90s — tribal fishers harvested a peak 350,000 pounds in the 2011 fishing season — the co-managers met in 2013 to improve the management strategy.

Starting with the 2014 fishing season, the co-managers incrementally reduced the annual harvest rate 1 percent per year for five years and closed the fishery in spring and summer when sea cucumbers spawn.

By 2019, WDFW noted an increase in sea cucumber density at the sites it regularly monitors, said Megan Russell, a shellfish biologist for the Lummi Nation. Furthermore, the joint state-tribal survey work of 2021 indicated continued improvements in the harvestable population in the San Juan Islands.

While the strategy appears to be working, the Lummi Nation is still cautious. One of four harvest areas is closed for conservation purposes, and the number of sea cucumbers allocated for harvest is still low. Tribal divers harvested 150,000 sea cucumbers in 2020, the most recent year for which data is available.     

Mueller’s report recommended a harvest size minimum of 25 centimeters, or 10 inches. “This would make sure that smaller sea cucumbers have a chance to reproduce,” Russell said. While the minimum size limit is not yet a requirement, co-managers have been gauging sea cucumber size and will determine in 2023 if size-selective harvesting should be implemented, Russell said.  

Top photo: Karl Mueller, shellfish biologist with the Lummi Nation Natural Resources Department collects a sea cucumber during a fall 2021 stock assessment in the San Juan Islands. Photos: Julie Barber, Swinomish Indian Tribal Community. Story: Richard Walker