The California Least Tern, a small migratory seabird and one of San Diego’s most endangered bird species, is having an increasingly difficult time nesting along our region’s coastline.
While the species has recovered in the last several decades (up from 600 nesting pairs in the 1970s to roughly 4,000 today), they continue to face many threats, including habitat loss, disturbance by beach-goers, and recent declines in their most crucial food source – northern anchovy.
Forage fish – i.e., the small fish that make up the center of the marine food web – have been declining off of our coastline for years, with the declines most severe for northern anchovy through 2016, when the population began to rebound.
Anchovy are considered to be the most important food source for many marine mammals, sport fish and seabirds, yet they continue to be managed passively, with catch limits that don’t change from year-to-year, regardless of variations in stock size.
As a key player in the marine food web, this is extremely worrisome, especially considering that anchovy numbers are known to fluctuate widely over short periods of time.
The use of fixed, long-term catch limits appears to be compounded by the effects of climate change.
Scientists estimate that the world’s oceans have absorbed roughly 90% of the excess heat that has been trapped in our atmosphere due to the burning of fossil fuels, and as a consequence our oceans have warmed significantly over the last several decades, driving complex changes in ocean productivity, and pushing many forage fish into deeper and cooler waters, out of reach of diving birds such as the Least Tern.
In 1998 the Pacific Fishery Management Council (PFMC, the federal body that oversees fisheries management on the West Coast) seemed to acknowledge the critical need to sustainably manage anchovy and other forage fish when it changed a part of its management plan to include catch limits “that preserve a portion of the stocks as forage for marine mammals and birds while maintaining a stable fishery.”
Yet in the 21 years since that language was adopted, little has been done to ensure adequate anchovy for ocean wildlife. Commercial catch limits that can be left in place for years at a time leave dependent predators at risk, especially when anchovy numbers are low.
On Friday, June 21st, the PFMC will consider whether to make changes to allow for annual anchovy catch limits that are based on the actual size and health of the stock. In light of the ongoing and poorly understood changes that our warming oceans are experiencing, a more holistic and precautionary management approach to such a key forage fish species seems appropriate.
Join San Diego Audubon and Audubon California this Friday, when we call on the PFMC to deliver on its 21-year-old pledge to sustainably manage anchovy and other forage fish for the benefit of marine ecosystems and our coastal economies.
By Megan Flaherty, Restoration Program Manager, San Diego Audubon Society
San Diego Audubon is a local environmental non-profit, providing outdoor education and volunteer opportunities to our communities for over 70 years. Find out how you can get involved with this and other conservation projects by contacting our staff at firstname.lastname@example.org.