Salmonids

of the Cariboo Chilcotin

 

Throughout the rivers, streams and lakes of the Cariboo Chilcotin, salmonids (salmon, steelhead, char and trout) play a vital role in the health of our ecosystems. Salmon are of great biological, social, cultural, and economic significance for the people and environment of British Columbia. They have provided food for First Nations peoples of British Columbia for thousands of years and, since the late 1800s, have supported an active commercial fishing industry, which was vital to the establishment and wellbeing of many coastal communities. Salmon from the Pacific Ocean are close to ten times more abundant than those found in the Atlantic Ocean. Chances are if you hike along a river bed late in the summer/fall or winter, you will see a flash of red from the bright coloured spawning salmonids. In our region, Sockeye, Chinook, Pink, Interior Fraser Coho, Kokanee and Rainbow Trout are frequently visible.

 

 

From the land-locked Kokanee and trout (including Whitefish, Rainbow Trout and blue listed Bull trout) to the anadromous (those that hatch in freshwater, migrate to the sea and when mature return to freshwater to lay their eggs) salmonids they are an important food source for wildlife and humans alike, also distributing valuable nutrients from the ocean to our region.

 

One feature that distinguishes salmonids from other fish is the presence of an adipose fin (located along their back between their dorsal and caudal or tail fin). Their strong caudal fin propels the salmon forward through rough water, strong currents and waterfalls, in order to travel from the ocean to their hatching grounds where they release eggs and sperm. Female salmonids use their tails to dig the redd (hollow) where they lay their eggs. She may build several redds and once her eggs are fertilized, she covers the nest with gravel. Shortly after spawning the adult salmon will die and fill the water with nutrients used by other fish, birds, and numerous other wildlife species.

 

Over the winter the young salmon begin to grow inside the eggs in their den of gravel. Only one in ten will survive. If the water gets too hot or cold, stops running (providing the egg with air absorbed through the egg wall) or dirt smothers the egg, it dies. In spring the fry (young fish) emerge, feed and grow in the stream, river or lake of their birth for up to two years. They are preyed on by ducks, herons and other fish predators. Those that survive will find their way back to the ocean where they will feed on abundant plankton, shrimp, crab, and small fish. Depending on their species, the salmonids spend from one to seven years at sea, feeding and growing. Once they return to freshwater, journeying back to their native spawning grounds, they do not eat. Living off stored body fat, these salmon battle their way home, arriving torn and scarred, most of their energy spent.

Each species of salmon has different spawning habits and is unique in appearance. With the exception of steelhead, spawning occurs in late summer and through the fall. The sockeye salmon, whose name is believed to be derived from the First Nations name sukkai, spawn in streams that drain into lakes. They remain in fresh water for up to three years before heading to the ocean, where they spend two to three years at sea. As they travel home to spawn, the sockeye turn a brilliant scarlet red with pale green heads. The males develop hooked jaws with large teeth. The sockeye's average age is 4-5 years and weight 2-7 kg. Sockeye are unique from other the salmon species in that they are almost always associated with lakes. The juveniles are dependent on lake ecosystems to feed on zooplankton for the first two years of their lives before migrating to the ocean. Chilko and Quesnel Lakes represent the most significant nursery lakes in the region where millions of juveniles from a variety of rivers such as the Mitchell, Horsefly, and Chilko are reared in annually. These lakes also support large numbers of beach spawners that utilize a variety of habitats from shallow shoals to deep water bench spawning to depths exceeding 45m.

Time of spawning for these stocks usually takes place between mid-September and early October and slightly earlier for the Upper Bowron River and Taseko Lake stocks. Unlike Chilko, Quesnel system stocks exhibit a four year pattern of production, characterized by one strong year followed by a moderately abundant year, then two relatively weak years. This pattern is referred to as cyclic dominance and is maintained by the high proportion of sockeye maturing at age four.

Chinook salmon are the largest of the salmon, averaging between 7-9 kg. Occasionally, a "tyee" or "king" is found, some reaching over 50 kg! Chinook are also called spring salmon because some populations or "stocks" return to their natal streams in the spring. Most of the chinook in the Cariboo/Chilcotin area display "stream-type" behaviour and over-winter in their natal stream feeding on insect larvae before migrating to the ocean as smolts in the second spring of their life. Chinook spawn in large rivers and are found as fry in many of the smaller tributaries of the Fraser River in our region. After spending up to a year in fresh water, they head for the ocean where they spend three to five years before returning to their spawning grounds. Spawning habitat ranges from small streams such as McKinley Creek to larger rivers such as the Chilko, where a combination of gravel and cobble located within a riffle or run is preferred. Time of spawning varies greatly among the different stocks of the Fraser River with the mid-river stocks, such as Quesnel and Chilcotin Rivers, spawning from early September to early October, while some of the upper river stocks, such as the Westroad and Bowron River, spawn from mid-July to late August. Many river systems have more than one stock of Chinook, some rivers having spring, fall and winter runs. Chinook are a unique salmon species because the flesh of adults can range in colour from white through pink to deep red. When spawning the Chinook becomes very dark in colour, some almost black.

 

Pink salmon, the smallest of the salmon species ranging in size from 1.5-3 kg, have a short, two-year life span. Soon after they emerge from the gravel spawning beds, the young pinks migrate to the sea. Some 18 months later, they return to spawn and die. Due to this short life cycle, there is no overlap between pink "stocks" from one year to the next. Two very unique stocks of pink salmon may use the same stream for breeding. Spawning habitat ranges from small tributaries of the Fraser Mainstem, such as Churn and Williams Lake Creeks, to larger rivers such as the Quesnel and Chilcotin and the mainstem Fraser. In the Fraser River, there is a predominately larger run of pinks in odd-years. The mature males are known as "humpies" due to the large hump they develop on their backs during spawning.

Our region is home to one of five Interior Fraser Coho salmon populations identified by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) designated as a unit. COSEWIC's concern is that the Interior Fraser Coho distribution has become too fragmented and that the genetic exchange within the populations will not be sufficient for their long-term survival. Interior Coho have a three-year cycle, averaging between 2 and 14 kg. Spawning in the streams emptying into the Fraser, the young Coho then spend the following year of their lives feeding and growing, preferring the cool water (15°c or less), and heavy vegetation provided in these streams. Small stocks exist in some of the tributaries of the Quesnel system, as well as the Chilcotin system. Juveniles emerge in spring and over-winter in small tributaries, backwater channels, ponds, and along lake margins associated with the natal stream. A unique aspect of juvenile coho is that they are very territorial, and consequently, their abundance and growth potential is limited by the available rearing territory and food supply. Spawning habitat is very diverse, ranging from small back channels and streams such as Wasko creek to larger rivers such as Chilko. Time of spawning for Coho is quite late compared to other salmon species and usually occurs from late October to mid-January. Maintaining healthy stream habitat is vital for the Interior Choose survival.

 

Telemetry studies, radio transmitters attached to the fish, have allowed the movement of summer run sockeye to be tracked along the migratory route from the lower Fraser River to their spawning grounds in the Chilcotin and Quesnel systems. The information gathered from these studies provides invaluable insight into migratory behaviour of salmon. Persons finding a spawned salmon with one of these transmitters attached is asked to return it to the nearest DFO office.

 

To further improve our knowledge on the various biological and stock assessment issues, a small, portable sonar system that produces video-like images using sound has recently been used by DFO. The Dual Frequency Identification Sonar (DIDSON) has the ability to confirm deep water lake spawning areas and observe associated habitat requirements and spawning distribution and densities.

Steelhead trout are the anadromous form of rainbow trout. They are born in freshwater streams where they spend their first 1 - 3 years of life, then migrate to the ocean where most of their growth occurs. After spending 1 - 4 growing years in the ocean, steelhead return to their native fresh water stream to spawn. Unlike Pacific salmon, steelhead do not necessarily die after spawning and are able to spawn more than once. Most steelhead spawn from December through April in small streams and tributaries where cool, well oxygenated water is available year round. Anadromous steelhead and resident rainbow trout did not arrive from two distinct evolutionary lines. Anadromous forms of trout can convert to resident populations when drought events or damming of rivers blocks their access to the ocean. Conversely, resident trout populations can become anadromous if ocean access becomes available. It is typical to have both life history patterns occurring in the same stream. In fact, resident and anadromous parents can produce offspring of both varieties. It has been speculated that there is a food availability trigger which determines whether a particular fish emigrates to the ocean or remains in the stream. It may be that if there is abundant food in the stream and a fish is growing at a rapid rate, it will remain in the stream. If food is limited and growth is slow, the fish will have a tendency to emigrate.

 

The rainbow trout, most widely distributed member of the trout family, is one of the top five sport fishes in North America. The rainbow has an elongated body, with an iridescent reddish band running along each side from head to tail. In the sea-run type, the back is dark blue, with sides and under parts silvery. In the non-migratory type, the back is bluish to olive green shading to silvery green on the sides and white over the belly.

 

The colour of the lateral stripe varies from light pink to a vivid red or reddish purple and is most pronounced in mature fish, especially breeding males. Sides, tail and dorsal fins are profusely dotted with small, dark spots. In general, large rainbows are caught in large bodies of water and small ones in streams and ponds. Rainbows that have migrated to sea or a large inland lake may weigh 6 - 97 kg. The rainbow trout is well adapted to both streams and lakes. While it prefers cold, clear, swift-flowing water, it can tolerate warm water. For a lake population to be self-sustaining, there must be a gravelly river to which adults can migrate during the spawning season. Rainbow trout spawn in the spring. The usual spawning site chosen is a bed of fine gravel in a riffle above a pool. The eggs hatch in approximately 4 - 7 weeks. The fry commence feeding about 15 days after hatching and their diet consists mainly of zooplankton. Adult rainbow trout are predacious and feed on aquatic and terrestrial insects, molluscs, crustaceans, fish eggs, minnows and other small fishes.

 

"Kokanee" is a native word meaning "red fish". Kokanee are the land-locked form of sockeye salmon. Because they never migrate out to the ocean to feed, Kokanee are much smaller than sockeye, but other than their size have very similar identifying characteristics as sockeye. Most Kokanee live in a lake for most of their lives and can usually be seen spawning near the edge of a lake or in a small tributary that feeds into the lake. Spawning time is generally during the month of September in the Cariboo-Chilcotin region. Average length for a Kokanee is 10-18 inches. Kokanee are food for numerous fish and waterfowl species such as rainbow trout, lake trout, burbot, mergansers, and common loon.

 

The blue-listed Bull trout is a predator, and as an adult eats almost exclusively other fish. Threats to the bull trout include loss of habitat and habitat damage, competition with introduced species and illegal poaching either intentionally or unintentionally through misidentification. A late-maturing species, the bull trout doesn't spawn until after it's sixth year. Bull trout require clean stream gravel and cold water temperature to survive. They are like "canaries in a coal mine", serving as an early warning system for habitat changes such as stream siltation. Studies have shown that when the amount of fine sediment (particles less than a quarter of an inch) amount to more than 40% of the stream bottom, less than ¼ of the bull trout eggs will hatch and survive to viable fry. Many anglers have a difficult time distinguishing bull trout from other species - particularly the lake trout. Both the bull trout and lake trout are chars: members of the trout family which generally have light spots on a dark background. The most reliable way of telling a lake trout from a bull trout is the tail. The lake's tail is deeply forked; the bull trout's tail fin is only slightly forked. The bull trout has a body that is snake-like and the head does not dominate the body. The names, bull trout and dolly varden, were used interchangeably until 1980 when the bull trout was genetically proved to be a separate species. There is no definitive way to identify bull trout from dolly varden in the field.

 

Whether you are watching grizzly, bald eagles, or black bear fishing spawning salmonids along the Atnarko River (Tweedsmuir Provincial Park), Quesnel Lake (Cariboo Mountains Provincial Park), the Bowron chain (Bowron Lake Provincial Park), or Horsefly River or Lake (Horsefly Provincial Park), the enjoyment of seeing the life cycle of a salmonid in completion cannot help but bring awe. Check out this salmonids of the Cariboo Chilcotin brochure to learn more.

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