Due to climate change, Vancouver seafood enthusiasts may soon see more Humboldt squid but less sockeye salmon on restaurant menus.
According to a recent study by UBC researchers, who looked at 362 menus from Vancouver restaurants from four different time periods, from 1880 to 2021, this is the case. They recognized locally caught species on these menus, and based on earlier research, they established the optimal water temperature for each species.
The highest preferred temperature was recorded in the present, at nearly 14 degrees Celsius, three degrees higher than in 1880, and nearly five degrees higher than the lowest temperature recorded in 1962. The researchers then calculated the average preferred temperature across all species identified for each of the four time periods.
These temperatures were in line with the current sea surface temperature trend, which saw an increase from roughly 10 degrees Celsius in 1980 to 10.7 degrees in 2021.
“We set out to discover if warming waters due to climate change are already affecting what seafood restaurants serve in their menus,” said senior author Dr. William Cheung, professor, and director of the UBC Institute for the Oceans and Fisheries.
“While it’s not a case of cause and effect, our findings indicate that the seas around Vancouver were warming during the studied time periods, so fish species that prefer warmer waters dominated there. It’s likely that they were more available to catch for sale, and so local seafood restaurants offered more of these types of fish.”
Two species, in particular, stood out: sardines, whose catches have decreased since the 1940s but which recent studies predict will increase again with warmer water in the future; and Humboldt squid, which have been extending their range further north as ocean temperatures rise.
“Humboldt squid is not something that we see in restaurant menus at all before the 1990s but we see it is much more common now, and sardine, which has historically disappeared in seafood menu, may return in the future,” says Dr. Cheung.
“Vancouver diners could expect to see both species featured more frequently on seafood menus in the near future,” he added. “We know sockeye salmon isn’t doing well in B.C. That means local sockeye might be less available in the near future, and it’s likely local restaurants may choose other salmon species or other fish species.”
Climate change is already affecting everyone, not only the fishermen who are catching the fish, but the people who go to restaurants and eat fish. We can expect to see less stable availability of seafood if we consume local catch. Expect that we may not be able to get all the same seafood year-round or all the time.
Dr. William Cheung
When compared to 2019 to 2021, when warmer water-preferred species tended to appear more frequently, those years saw the largest variations in the species found on menus.
“That’s when lots of the bigger changes in temperature occurred, and that’s also the time when some of those changes are really starting to have bigger and more obvious effects on the fish stocks,” Dr. Cheung said.
“The extreme marine heat wave known as ‘the Blob’ and the abnormally hot weather of the past several decades, leading to shifts in distribution and abundance of exploited species, could be behind the increased pace at which seafood menus are transforming,” he said.
“Climate change is already affecting everyone, not only the fishermen who are catching the fish, but the people who go to restaurants and eat fish,” he said. “We can expect to see less stable availability of seafood if we consume local catch. Expect that we may not be able to get all the same seafood year-round or all the time.”
“Other non-climate related factors do affect the availability of species that restaurants have to serve, such as fishing activity, aquaculture, and imported supply. The researchers tried to account for these uncertainties in various ways, and the research highlights a trend that is related to the changes in ocean temperature,” says Dr. Cheung.
“Given the other evidence of how fish and fisheries are responding to climate change, the trend we detected is likely to also be related to the changing oceans.”
According to study co-author John-Paul Ng, a UBC undergraduate student, and researcher, the study emphasizes the value of different data sources. In contrast to other fishery data, menus are typically free and easily accessible online.
“People go to restaurants every day. I think drawing the line from science to something that is very relatable for people in the real world is something the study accomplishes,” he said.
“Future studies could use other unorthodox materials, such as cookbooks, and even paintings from local artists who focus their work on the ocean, to gain insight into the shifting distribution of marine life,” he added.
