What is a Pacific Salmon?
Pacific Salmon may be Chinook, Chum, Coho, Sockeye, or Pink salmon. The Atlantic Salmon is not native to the west coast of North America, but it is commonly raised in aquaculture operations. Pacific Salmon are part of the genus Oncorhynchus, which includes also includes Cutthroat and Steelhead Trout; these species are often collectively called salmonids.
The salmon is among the most revered of coastal animals, for its cultural and spiritual importance to First Nations, its world-famous tasty flesh, and its role in the historical economy of BC The most common salmon in our local waters are Chum and Coho. All Pacific salmon species are anadromous, meaning they spend most of their life in the ocean but migrate to fresh water to breed. They therefore interact with several different ecosystems, and play important roles in terrestrial, freshwater and marine food webs.
Where do Pacific Salmon live in the Victoria area?
Historically, many streams in the Victoria area supported salmon spawning runs, and numerous wetlands provided rearing habitat for juvenile salmon. As the city grew, many of these areas were lost altogether, through in-filling, paving and development. Others have become degraded, so that salmon cannot survive there anymore (see What threatens Pacific salmon, below). However, largely thanks to the restoration efforts of community stewardship groups, salmon are returning to several streams in the CRD.
Colquitz Creek flows into Portage Inlet. Between 200 and 400 wild Coho, and some dozens of wild Chum salmon, spawn in this creek each year. Although these runs are probably much smaller than in historic times, they are a rare asset for an urban stream, particularly because the stocks are not enhanced with hatchery fish.
Craigflower Creek also flows into Portage Inlet. Most of the salmon in Craigflower Creek were wiped out in the 1970s, due to in-stream barriers caused by road construction and other development. In the 1980s, some parts of the stream were restored, and juvenile Coho were transplanted from Goldstream River. Recently, restocking has ceased, and the returning populations seem to be stable. The protected habitat in Portage Inlet and the Gorge Waterway, including extensive eelgrass beds, is crucial to the survival of juvenile salmon.
Millstream Creek flows into Esquimalt Harbour. This stream may have supported limited salmon runs in the past, despite natural in-stream barriers (e.g. waterfalls) that probably limited the numbers. Changes to the water flows of the stream due to extensive impervious surfaces has made these barriers virtually insurmountable. Some restoration work has been done to create “fishways” that bypass the barriers, and Coho salmon have returned. The spawning population is approximately 150 and is not currently restocked.
Colwood Creek, Bee Creek and Selleck Creek flow into Esquimalt Lagoon. These creeks also probably supported salmon spawning in the past, but only Colwood Creek still does today, with very small numbers of fish. The excellent nearshore habitat in Esquimalt Lagoon make these creeks good candidates for restoration work.
How do Pacific Salmon live and reproduce?
Salmon lay their eggs in the gravel beds of fresh water streams. The female scoops out a nest or “redd” with her tail by turning on her side and fanning vigorously. The eggs are immediately fertilized with sperm by a male waiting nearby. The female then covers the eggs with gravel, and both adults shortly die. By spring, the eggs develop into alevins, tiny larvae that are nourished from a yolk sack attached to their bellies. They live in the gravel until the yolk is consumed, and then emerge as 2.5 to 5 cm fry. Fry feed mostly on aquatic insects.
Chum and Pink fry immediately head out to the sea, whereas Coho, Chinook and Sockeye may stay in the stream for up to two years. When the salmon head to the sea, they are called smolts, and undergo physiological changes that allow them to tolerate salt water. Estuaries at the river’s mouth provide a transition zone to the open ocean. Here, the smolts can acclimate to the salt water, and feed on plentiful small fish and invertebrates in a sheltered environment.
Once in the ocean, salmon may migrate long distances to feeding grounds, or they may stay in local areas as do some Chinook in the Georgia Strait and Puget Sound. Most salmon return to the same stream where they were hatched. Coho spawn when they are three years old, and Chum when they are 3 or 4. The differences in life histories between species are summarized in the table below.
Table 1: Summary of salmon life histories, by species (1)
|Time Rearing In Freshwater||1 month to 1 year||hours to days||most 1-2 years||hours to days||1 to 2 years|
|Primary Early Rearing, Habitats||stream, estuary||estuary||stream||estuary||>lake|
|Time Spent At Sea||1.5-4.5 years||2.5-4.5 years>||0.5-1.5 years||1.5 years||1.5-3.5 years|
|Avg Age at Maturity||(range 2-8)||(range 2-7)||(range 2-4)||2||(range 3-8)|
|Avg Forklength & Weight at Maturity||90 cm & 16 kg||65 cm & 5.5 kg||55 cm & 4.5 kg||45 cm & 1.8 kg||65 cm & 2.3 kg|
The Life Cycle of a Salmon
What kind of habitat do Pacific Salmon require?
For breeding and rearing, salmon need healthy freshwater streams characterized by: clear water; abundant oxygen; plenty of shade from streamside vegetation; hiding spaces (e.g. overhanging banks and fallen logs); clean gravel; sufficient nutrients; and healthy insect populations. Stream flow is also crucial: insufficient flow can strand smolts and cause increased competition, while excessive flow can wash juvenile fish out to sea prematurely, and destroy important channel characteristics.
Healthy streamside vegetation (including reeds, sedges, willows, shrubs and trees) helps to soak up water and protect stream banks from erosion in times of high flow. Streamside vegetation also provides nutrients and habitat for the insects that juvenile salmon prey upon. Large woody debris such as fallen trees helps to create pools and sheltered areas for spawning adults and juvenile salmon to rest and hide from predators.
Estuaries are also important habitats for juvenile salmon. Chum in particular are known to spend up to a month in estuaries.
In the ocean, salmon feed on fish, squid and crustaceans. They generally feed in areas along the coast of Alaska, B.C. and California where south-flowing currents create “upwelling” of cold water and nutrients from deep in the ocean. Plankton feed upon these nutrients and form the foundation of the food web. Upwelling can be affected by El Niño and other climate fluctuations.
How have people used Pacific Salmon?
Pacific salmon played a pivotal role in the culture and sustenance of Coast Salish people in this area. Salmon were were caught with a variety of techniques, and eaten fresh or smoked.
After the city of Victoria was established as a Hudson’s Bay fort in 1843, European arrivals also fished salmon, for sustenance, sport and commercial purposes. Many people, including First Nations, sports and commercial fishers, continue to harvest salmon today. However, salmon stocks have substantially declined from historic levels, and fisheries are consequently more strictly controlled. In salmon aquaculture, Atlantic salmon is the species most commonly farmed, usually in net-cages open to the ocean.
The largest fishing industry in terms of contribution to BC’s Gross Domestic Product (GDP) is the sports fishery. Overall, fishing industries (including commercial, sports, aquaculture and fish processing) comprise about 0.5 percent of the total GDP of the province, and generate 20,000 jobs (one percent of total jobs).
Salmon continue to form a part of the image of coastal life in BC and draw tourists from around the world. Salmon figures strongly in First Nations and other local art, and graces the tables of local gourmet restaurants.
Why is Pacific Salmon important?
Salmon are food for many predators (including humans), as well as for scavengers and decomposers. Some examples of the many animals that feed on salmon in various ecosystems include:
- In the ocean, sharks and other fish, seals, sea lions, dolphins and Orcas, sport and commercial fishers
- In the estuary, river otters, sea lions, bears, and birds
- In freshwater (as spawning adults), bears, raccoons, eagles, sport and First Nations fishers
- In freshwater (as dead adults), ravens, gulls, coyotes, trout and juvenile salmon, insects
- In freshwater (as eggs, fry and alevin), ducks, wading birds, gulls
The decaying carcasses are also important nutrient sources for vegetation. For example, when bears feed on spawning salmon and bring them into the forest to eat, the decaying left-overs provide important fertilizer for the trees. In the course of their lives, salmon therefore transport nutrients derived from deep ocean upwelling all the way to inland forests. It is these kinds of connections to many ecosystems that makes the salmon a “keystone species.”
What threatens Pacific Salmon?
Loss of spawning and rearing habitat is a major factor in the decline of local salmon stocks. This occurs when wetlands and estuaries are filled in for construction of buildings and roads, and when streams are placed in culverts and otherwise modified.
Removal of streamside vegetation is a common consequence of development and has a number of effects
- banks become more prone to erosion, which can cause excessive sediment to cover gravel spawning beds and clog fish gills
- water temperatures rises due to a lack of shade
- less decaying vegetation is available to nourish salmon prey
Another form of habitat loss results from shoreline or stream bank armouring, for example with seawalls or large rocks. Degraded water quality in streams and harbours results from pollutants such as oils and gasoline from roads and boats, household wastes disposed of in storm drains, lawn/garden fertilizers and pesticides, and industrial chemicals. Some of these pollutants are directly toxic to salmon, while others have indirect effects; for example, fertilizers cause excessive algae growth that robs the water of oxygen.
Excessive water flows result when large areas of the watershed are paved. Instead of slowly soaking into the ground and filtering through soil and roots, rainwater can then rush straight into the streams with a great amount of force. This can contribute to erosion, and destroy stream features that previously provided shelter for young fish.
How can I help protect Pacific Salmon?
For information on protecting salmon, please visit our How Can I Help section.