Healthy Oceans. Healthy Communities.

Herring Spawn

Each year in early spring, tens of thousands of tonnes of herring migrate from offshore to nearshore habitats to spawn en masse in one of nature’s most spectacular events. Nearshore waters flow chalky white with herring milt and eggs, drifting for kilometres along the coastline. The spawning herring and their eggs attract an abundance of predators – at a time when food resources tend to be low – that will forage for several weeks1.

Other than salmon, few species in B.C. are as ecologically, culturally or economically important as the Pacific herring. They are one of the most abundant fishes in B.C.’s coastal waters and are a cornerstone of the marine food web, directly supporting salmon, seals, sea lions, whales and many seabirds. They have also fed coastal First Nations for thousands of years2. Today the commercial herring fishery provides employment for thousands of Canadians3.

The effect of an oil spill on herring could be drastic and long lasting. Scientific studies from Prince William Sound (the site of the infamous Exxon Valdez spill) have shown that herring there have not recovered after more than 20 years4.

Data Source:
The herring spawn points displayed on the map show the locations of one kilometre sections of the coastline that have been ranked by Fisheries and Oceans Canada (DFO) based on the long-term frequency and magnitude of herring spawn events along the B.C coast. The rankings were grouped into classes based on DFO’s methodology and the classes are displayed as stars in the balloon for each site as follows:

6 stars = vital = the top 5% of the herring spawn records
5 stars = major = the next 10% of the herring spawn records
4 stars = high = the next 15% of the herring spawn records
3 stars = medium = the next 20% of the herring spawn records
2 stars = low = the next 25% of the herring spawn records
1 star = minor = the last 25% of the herring spawn records

This classification was performed for all herring spawn records along the B.C. coast. Herring spawn coast wide in B.C. but only those ranked coastline points within the map study area on the North and Central Coast of British Columbia are displayed here5.