Pacific sardines are a small but sometimes numerous fish closely intertwined with California’s fishing history. A new study linking climate change and the northern sardine stock fishery shows that they may shift north along the West Coast as the ocean warms.
A climate-driven northward shift by sardines could cause a decline in landings of the northern sardine stock by 20 to 50 percent in the next 60 years. These changes would affect historic California fishing ports such as San Pedro and Moss Landing, according to the new research published in Fisheries Oceanography. The study did not examine whether southern sardine stock would also shift northward, potentially offsetting this decline in landings. In turn, landings at northern port cities such as Astoria, Oregon, and Westport, Washington, are projected to benefit.
“The potential impact of a shifting Pacific sardine distribution on U.S. West Coast landings” can be found here.
Researchers examined three possible “climate futures.” The warmest had the most pessimistic outcomes, with total sardine landings in all West Coast states declining 20 percent by 2080.
The study translates environmental shifts into possible impacts on fishing communities and coastal economies. Sardines have historically gone through “boom and bust” changes in their population. Their numbers off the West Coast have remained low in recent years, with the West Coast sardine fishery closed since 2015. This research does not project changes in the abundance of sardines. Instead, it shows that climate-driven shifts in their habitat may have a significant impact on landings at historically important ports.
“As the marine environment changes, so too will the distribution of marine species,” said James Smith, a research scientist with the University of Santa Cruz affiliated with NOAA Fisheries’ Southwest Fisheries Science Center. “But linking future changes in the distribution of species with impacts on the fishing fleet has been challenging. Hopefully our study can provide information about potential impacts in coming decades, and thereby inform strategies to mitigate these impacts.”
Maps illustrate projections of how sardine habitat off the West Coast will shift as climate change warms the ocean. Blue shading illustrates where habitat will improve for sardines over coming decades, while red shows where habitat will grow worse. Credit: Fisheries Oceanography.
The estimated shifts illustrate how climate change may alter the traditional fishing economies of the West Coast, as once depicted in John Steinbeck’s “Cannery Row.” The 1945 novel featured historic canneries in Monterey, once supplied by sardine catches delivered to nearby Moss Landing. Sardines helped make Monterey one of the busiest fishing ports in the world until their collapse in the 1950s.
Sardines are well known to undergo boom and bust cycles. Their numbers, and landings with them, increased again in the 1990s, but have declined more recently. The new research does not attempt to project changes in sardine numbers, but uses recent numbers as a baseline. It demonstrates how average landings by port may change due to future shifts in sardine habitat.
“We can’t predict how many sardines there will be in 50 to 60 years,” says James Smith, “but we have a much better idea where they will be. And their northward shift [of the northern sardine stock] promises to have a significant impact on the fishery, regardless of how many sardine there are.”
The study aligns with earlier research indicating that many marine species, including sardines, will follow their preferred temperatures north as climate change warms the Pacific Ocean. The new research estimates the northward shift in sardine, and its potential impact on the fishing fleet. These findings emerged from newly developed and very fine-scale projections by climate and ocean models of changes in ocean conditions along the West Coast.
There are three stocks of sardine: northern, southern and Gulf of California. The research examined the northern stock, which can range from southeast Alaska to the northern portion of the Baja Peninsula, not the Gulf of California stock or the southern stock typically found mostly in Mexican waters off the west coast of Baja California but sometimes ranging into Southern California. Researchers noted that a northward shift by the southern stock may help offset the projected declines in landings at southern ports.
— CBB, Sept. 29, 2017, WARMER NORTHWEST WATERS HAVE FISH MOVING NORTH, SPAWNING EARLIER, LONGER OFF PACIFIC NORTHWEST https://www.cbbulletin.com/warmer-northwest-waters-have-fish-moving-north-spawning-earlier-longer-off-pacific-northwest/