Pacific Herring
Biomass of spawning Pacific herring
The biomass of spawning Pacific herring indicator is the estimated annual tonnage of herring that are reproducing 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.
Herring VS Figure 2020.JPG
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. The 2020 targets are shown with a dot for each stock.

Key Indicator Results

Due to the COVID-19 pandemic, WDFW surveys were interrupted near the peak of herring spawning, and some spawning areas were not sampled thoroughly or at all. Citizen reports and photo documentation of spawning events was critical to documenting the timing, location, and extent of spawning in 2020. The reports and images showing herring spawn intensity that were provided to us during this period when we were unable to complete surveys has allowed us to document and account for spawning events that would have otherwise been unknown to us. Based on these reports, we added roughly 800 tonnes of spawning biomass to the estimates generated by our surveys.

  • 2020 was an exceptional year for herring and herring surveys in Puget Sound. The total herring spawning biomass in 2020 was estimated to be 18,559 tonnes. This was a 235% increase over the 2019 estimate and is the highest estimate since the 1980s. This dramatic increase illustrates the dynamic nature of these stocks and their ability to respond when conditions are favorable.
  • As seen in 2019, but to an even greater extent, several spawning events in 2020 were notable because they occurred at the fringes or outside of the times and areas where most recent spawning activity had been documented.
  • Despite the dramatic increase in 2020, the 4-year rolling average of the ‘Other Stock’ complex spawning biomass remains barely below the 25-year baseline set in 2010.
  • Four ‘Other Stock’ complex stocks, Quilcene Bay, Port Orchard/Port Madison, Purdy Bay, and Elliott Bay had the greatest spawning biomass ever recorded for any of these stocks. The Quilcene Bay stock and Port Orchard/Port Madison stock were both estimated to be over 7,000 tonnes, and together accounted for over 75% of the total 2020 herring spawning biomass estimate in Puget Sound.
  • Not all stocks shared in the increased productivity in 2020. Several stocks, such as Port Susan and South Hood Canal, continued to decline, while others, such as Wollochet Bay remained at undetectable levels.
  • The Cherry Point herring stock, once the largest stock in the Sound, has declined by over 96% since the earliest sampling date in 1973 and shows no sign of recovery. However, it should be noted that the Cherry Point stock surveys were curtailed due to COVID-19 in 2020, and we expect that the 2020 spawning biomass was greater than the 274 tonnes we were able to document.
  • The Squaxin Pass stock rebounded from its 2019 record low of 14 tonnes to 110 tonnes in 2020, but still remains below its 2020 recovery target and its 25-year baseline.
  • Owing to natural fluctuations in abundance as a consequence of oceanographic and climatic parameters, the Squaxin and 'Other Stocks' complex may reach their respective recovery target values over the next five years. However, there is no evidence to suggest that herring spawning biomass at Cherry Point will increase in the near future and none of the stocks have reached the 2020 recovery targets that were set in 2010.

Contributing Partners

Recovery Target

Increase the overall amount of spawning herring throughout Puget Sound to 19,380 tons (17,581 metric tonnes). For each stock, the targets are:

  • Cherry Point: 5,000 tons (4,536 metric tonnes)
  • Squaxin Pass: 880 tons (798 metric tonnes)
  • All other stocks: 13,500 tons (12,247 metric tonnes)
Data Source

Washington State Department of Fish and Wildlife, Marine Fish Unit (Forage Fish)

Methods and More Results
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