The biomass of spawning Pacific Herring indicator is the estimated annual tonnage (four-year average) of herring that have reproduced in Puget Sound. Estimates are based on surveys of the density and extent of eggs deposited by herring on marine vegetation. Herring, along with a few other small schooling fish species, play a unique role in the food web: they are an essential source of food for larger fish, seabirds, and marine mammals.
Four-year average spawning biomass estimates for three genetic stock groups and the combined total are shown with dashed and solid lines; dashed lines represent periods of incomplete data; each color corresponds to a different stock group, and black is the combined total of all stocks. The 25-year mean (1986-2010) for each stock is referenced as a baseline and is shown with horizontal dotted lines of corresponding colors.
Key Vital Sign Indicator Results
- We estimate 8,862 metric tons of total herring spawning biomass for the southern Salish Sea in 2025. This is a decrease of about 22% from the estimated spawning biomass in 2024 (see the "Datasets" section below to download a table of annual biomass estimates).
- In 2025, the 4-year average spawning biomass for the Other Stocks Complex (all Puget Sound herring stocks other than Cherry Point and Squaxin Pass) declined by 379 metric tons to about 12,355 metric tons. This is still a relatively high average compared to the last two decades as the result of the high spawning biomass in 2023 and the above average spawning biomass in 2022 and 2024. In contrast, the 4-year averages of the genetically distinct Cherry Point and Squaxin Pass stocks remain well below their baselines. Therefore, our conclusion about progress of Pacific Herring stocks in Puget Sound remains as “Mixed Results."
- After two year of not observing spawning for the Cherry Point herring stock, spawning was observed at Cherry Point again in 2025.
- We confirmed herring spawning in Oro Bay in South Puget Sound during the 2025 season. The estimated spawning biomass was small (22 tonnes), but notable for occuring in May, which is later than any stock in the region other than Cherry Point.
- For the first time in over four decades of surveys we failed to detect spawning in the Samish/Portage Bay spawning area.
- No new record high spawning estimates were observed in the 2025 season, but the Port Orchard/Port Madison, Purdy Lagoon, and Semiahmoo Bay spawning areas all remained above 1,000 metric times each.
- During the 2025 season with the reduced spawning activity, we also observed few shifts or expansions in spawning distribution.
Contributing Partners
Target
No targets are currently set for this indicator.
Data Source
Washington State Department of Fish and Wildlife, Marine Fish Unit (Forage Fish)