Jan. 31 (UPI) -- Can a small, pink species help fishermen sustainably meet the rising demand for sea urchin? Some California researchers suggest eaters might not have a choice.
Red sea urchins and their roe are a popular delicacy in Asia, and their popularity is rising in the United States too. That's bad news for a fishery facing a number of environmental stressors, including rising ocean temperatures and acidification, as well as decreased oxygen levels.
"The fishery saw unprecedented reductions in marketable wild-caught urchins after the 2014 warm blob and 2015 El Niño, which decimated kelp forests -- the primary food source for urchins -- throughout California," researcher Kirk Sato said in a news release.
Sato, who now works at the Okinawa Institute of Science and Technology in Japan, began researching the potential of the pink sea urchin, Strongylocentrotus fragilis, as an alternative food source while he was a doctoral student at the Scripps Institution of Oceanography at the University of California San Diego.
Sato first observed the sea urchin's unique adaptability while studying the impacts of climate change on deep-sea species. While other species were becoming less abundant, the pink sea urchin was thriving.
Though small and delicate in appearance, its population growth proved the species was surprisingly hardy.
"Throughout the course of my dissertation, I also learned that pink urchins were also commonly found as bycatch in spot prawn traps, but they needed to be released because there was no market for them," Sato said.
He and his colleagues set to find out of a new and sustainable market could be created for the hardy species.
With the help of research advisor Lisa Levin and Dave Rudie, owner and founder of Catalina Offshore Products, Sato began analyzing trawl and bycatch data to better understand where the species can be caught and when. The analysis suggests most pink sea urchins are found between 820 to 984 feet beneath the surface of the ocean. The data also suggested the species produces most of its roe during the winter. If they were legal to harvest, prawn fishermen could sell the urchins that end up in their traps.
Still, the problem of demand remains. Early results suggest the pink sea urchin roe offers a distinct umami flavor, but the species' roe is smaller and lighter than the roe of red sea urchins.
"We don't necessarily think pink urchins are a viable replacement for red urchins in the future given how much smaller their roe is on average," Sato said. "However, in light of recent increasing demands for sea urchin worldwide and the potential impacts of climate change on red urchins, aquaculture efforts or supplemental harvest of an underutilized species such as pink urchins may be a foreseeable next step."
Scientists say it's important to continue to look for new ways to relieve the pressure on vulnerable commercial seafood species, and that includes finding new sources.
Sato and his research partners published their analysis of the pink sea urchin this week in the ICES Journal of Marine Science.