Please join us on October 16th at 5:30pm at the Dungeness River Nature Center to help celebrate another successful year at the Salmon Coalition!

We’ll first take you on a short walking tour at the Nature Center to learn more about the native plants we use in our riparian efforts, such as the riverbank lupine in the image to your right!

Then our guest speaker, ƛ̕əw'cən Mackenzie Grinnell, Traditional Foods & Culture Gathering Coordinator with the Jamestown S'Klallam Tribe, will join us to talk about how the work they do parallels the work of NOSC.

We’re also excited to share with you the programmatic work we’ve done over the past year. We have a lot of exciting updates!

We invite you to bring a pie to share with the community to celebrate in true Salmon Coalition fashion! Savory pies are especially appreciated. Remember to please dress appropriately for the initial walking presentation outside. We will send more details closer to the date.

We look forward to seeing you on October 16th at 5:30pm!

Dungeness River Nature Center

1943 W. Hendrickson St

Sequim, WA 98382

Photos by NOSC Staff.

Eyed-eggs. Photo by Debbie Frost with NOAA. Salmon Life Cycle - State of Salmon (wa.gov)

by Cheryl Lowe

Fall is a great time to watch spawning salmon in local streams, splashing as they work their way upstream to create redds (nests) in the gravel. Many of us are familiar with the sight (and smell) of carcasses after spawning salmon die, but what about the eggs? A female salmon may lay between 1,000 and 5,000 eggs, depending on species and its health/size/age. After spending an afternoon last month helping kids explore Fin, NOSC’s giant salmon, I began to wonder what happens to all those eggs.

Egg Deposition

Eggs (also known as roe) vary in size by species and size of individual females. Sockeye salmon eggs are the smallest of the Pacific salmon--on average only 1/4 inch in diameter. Chum salmon eggs are the largest, at 1/2 inch in diameter. 

Egg fertilization must take place within seconds of the female salmon releasing her eggs. The egg is protected by a thick outer membrane with a single “opening” called a micropile through which the sperm swim to fertilize the egg. Contact with fresh water triggers a change in the protective membrane; the egg becomes firm within about 20 seconds after exposure to fresh water and the micropile closes. The membrane hardening process is induced by the absorption of water (due to an osmotic gradient difference). In those first seconds, the absorption process may help carry the sperm through the micropile.

Salmon sperm (carried by the cloud of milt) undergo a similar hardening when exposed to fresh water; after 10-20 seconds in the water, sperm are less likely to successfully fertilize an egg. This helped me understand why the males are so competitive about positioning themselves right next to the female as she prepares to release her eggs.

The female salmon moves quickly to cover her eggs with gravel soon after spawning to protect them from being washed downstream. The firmness of a salmon egg is completely independent of fertilization; unfertilized eggs will remain water-hard for weeks within a redd, but no embryo develops in those eggs.

Upper right: chum salmon releasing milt. Photo courtesy of John McMillan with NOAA. Salmon Recovery 101 - State of Salmon (wa.gov). Above: Salmon eggs hatching into alevin. Photo by Friends of the Issaquah Salmon Hatchery The Salmon Life Cycle (issaquahfish.org)

Egg Development

Once fertilized and water hardened, the ultimate success or failure of egg development is determined by temperature, water quality and flow. Most important are temperature, dissolved oxygen, carbon dioxide, pollutants and gravel size.

Water temperatures in a given stream or river are influenced by the size of the river, the source of its water and geography as well as seasonal weather patterns. If the water is colder than usual, egg development is slower. In general, ideal water temperature for salmon eggs is from 5°-11°C (41°-52°F). Eggs develop more slowly at lower temperatures, so in colder streams, returning salmon might have evolved to arrive earlier in the season to allow for longer development time.

Dissolved oxygen is also essential for developing salmonid embryos. Lower levels of dissolved oxygen will slow embryonic development and result in reduced growth rate; low oxygen levels have been linked to deformed embryos and can cause death.

Carbon dioxide is a normal waste product of the developing eggs. As salmonid embryos develop, carbon dioxide must be transported out of the egg. If insufficient water movement occurs across the eggs, excess carbon dioxide creates pockets of acidified water that can damage egg development.

Pollutants exhibit a variety of effects on developing embryos, including acute mortality, developmental delays, developmental alterations, chronic mortality, and even permanent genetic mutations. For example, studies of the long-term effects of the Exxon Valdez oil spill on pink salmon embryo survival demonstrated that increased embryo mortality was apparent in oil-contaminated lineages generations after the spill and occurred in both contaminated streams and in lineages moved to uncontaminated streams. In other words, the contamination permanently affected the fish’s germ line.

Gravel: Spawning salmon build their redds in stream areas that have the “right” mix of gravel sizes. They are looking for sufficient flow to provide oxygen exchange but enough sediment stability to prevent wash-outs during high water events. Flooding can wash out redds and send the eggs into the stream, where they are often eaten by other fish and birds.

What else might happen to the eggs? Depending on timing, some redds could also be disturbed by later arriving females excavating in the same area. A number of factors are at play here including early vs late arriving spawners of various species, larger fish digging deeper redds that are less likely to wash out, and if higher numbers of salmon are spawning in a given year.

Successful egg development is only the first of many challenges facing a new generation of salmon. As I watch salmon working their way upstream, I now do so with a much greater appreciation for what comes next in the fascinating life story of these amazing fish. 

Salmon redd circled in blue. Photo courtesy of Trout Unlimited - Redd Surveys Shaping Priorities In Michigan’s Pere Marquette - Trout Unlimited

Resources:

The Behavior and Ecology of Pacific Salmon and Trout. Thomas Quinn. 2018. University of Washington Press.

Salmon Eggs: FAQ on US Fish and Wildlife website.

https://www.fws.gov/sites/default/files/documents/08_Salmon%20Facts%20Cards-Eggs_1.pdf

“Salmonid Embryo Development and Pathology” by G. Russell Danner, Maine Department of Inland Fisheries & Wildlife. https://fisheries.org/docs/books/54065P/3.pdf

Life Stage Cheat Sheet for Pacific Salmon Egg Stages

https://www.fws.gov/sites/default/files/documents/06_Life%20Stage%20Cheat%20Sheet.pdf

To many Washington residents, orca whales are an icon of the Pacific Northwest. Unfortunately, Southern Resident orcas that inhabit Puget Sound and coastal waters are in peril. A combination of noise and crowding by boat traffic, pollution, and food scarcity make Southern Residents among the most at-risk marine mammals on the planet.

Unlike Transient orcas, who also occasionally inhabit Washington waters, Southern Resident orcas do not eat abundant marine mammals like seals and sea lions. Instead, they dine exclusively on fish, with Chinook salmon representing most of their diet. However, recent research has shown that when Chinook are scarce, Southern Residents will supplement their diet with other salmon species, particularly chum and coho salmon. One of the best things we can do to support orca whales is to restore the habitat of their preferred prey—salmon.

Join NOSC October 14th for Orca Recovery Day as we team up with the Jefferson Conservation District and the Jefferson Land Trust to revegetate a portion of the Snow Creek Estuary in Discovery Bay, home to ESA-listed Hood Canal Summer Chum salmon and several other salmonids. Improving salmon habitat leads to increased numbers of fish, something the Southern Residents are in dire need of.

Volunteers plant native species in Discovery Bay in 2022 for Orca Recovery Day. Photo by NOSC Staff.

Volunteer for Orca Recovery Day!

Saturday, October 14

10am - 12:30pm

31 Fairmount Road, Port Townsend, WA 98368

Please bring the following:

• Gloves
• Water Bottle
• Snacks
• Layers for fall weather

Saturday, October 21st

6-8pm

at Wind Rose Cellars

143 W Washington St, Sequim, WA 98382

We'll have fun salmon activities for kids of all ages! Fin the Giant Migrating Salmon will be swimming over to Peninsula College for the event.

We will have NOSC t-shirts, sweatshirts, and puzzles for purchase as well.

Interested in volunteering at our booths or with Fin? Please email Education & Outreach Coordinator, Lindsay McCord, at lmccord@nosc.org for more information or to sign up.