THE SALMONIDS

Habits and History of Salmon

There are seven species of North American Pacific salmon: chinook, chum, coho, cutthroat, pink, steelhead and sockeye. Although each species has a unique appearance and different habits, they share many characteristics. They are anadromous - meaning their eggs are laid and hatch in freshwater, and their young spend at least some of their early lives in freshwater before swimming to the sea to grow and mature. Their ability to find their way home again when it is time to reproduce is one of the most remarkable things about salmon. In fact, salmon have been known to travel thousands of kilometres in the ocean, as well as battle strong river currents and waterfalls to reach their hatching place. Pacific salmon, with the exception of cutthroat and steelhead, spawn only once and die within days of digging their nests or "redds" in the gravel and mating. Their bodies float down rivers and decompose, filling the water with nutrients for other species of animals and plants. Live and dead salmon are also important food for birds like eagles and gulls, and mammals such as bears and otters. In this way, salmon contribute to the health of freshwater ecosystems.

Salmon lay their eggs in nests or "redds" that the females dig in the gravels of streams or in some cases lakeshores. The gravel must be free of silt and well oxygenated. Young salmon require cold, clean, well-oxygenated water. They are very sensitive to any activities that reduce the quality of their freshwater habitat. Industrial activities like forestry and farming, and other human activities like building roads and cities, can damage or destroy freshwater salmon habitats if they are not carried out in an environmentally friendly manner.

Coho and chum are the most populous species in Bowen Island streams. Chum, while one of the larger species, are poor jumpers and thus will be found spawning in the lower reaches of Bowen streams, often just inside the mouth of the stream. Coho will attempt to find spawning beds in the upper reaches of streams and the Bridle Veil Falls ladders were installed to expand coho habitat to the higher area of both Terminal and Killarney Creeks.

Cutthroat trout are also found in many Bowen streams and lakes and recently local residents have found small numbers of Kokanee (see Sockeye below) in Grafton Lake and the small streams that feed the lake.

The best place to find coho and chum spawners, in mid to late October, is the gravel beds just inside the causeway at the mouth of the Terminal/Killarney Creek watershed, just a short walk from the Snug Cove ferry terminal.

Coho (Oncorhynchus kisutch) can be found in most waters that drain into the Pacific Ocean, so there are more populations of coho than of any other Pacific salmon species in British Columbia. Young coho generally spend one year in freshwater although in northern populations, high proportions of juveniles spend two or even three years in freshwater before entering the ocean. Juvenile coho favour small streams, sloughs and ponds, but coho populations can also be found in lakes and large rivers. In some coastal streams, large numbers of newly emerged fry appear to move to the ocean like chum and pink. Coho juveniles are territorial while in freshwater and will vigorously defend their territories against other coho and trout. Juvenile coho can be brightly coloured with orange-red bodies and dramatic black and white edges on the anal and dorsal fins. While defending their territories, they make threatening displays by turning sideways to the intruder and spreading their fins to make themselves appear as large as possible. At the same time, the small fish can shimmy and shake in a display called the "wig-wag dance". This and other behaviour of young coho have been widely studied.

Coho

 
There is only so much space for territories in streams so the number of young coho is limited and there is intense competition for what space there is. Individuals that cannot find or defend a territory do not survive well. A consequence of this territoriality is that a stream tends to produce the same number of smolts year after year regardless of the number of adults that spawn in it. That average number of smolts is called the "carrying capacity" of the stream. Unlike the other salmon species, which generally migrate long distances in the open ocean, coho remain in coastal waters. Their proximity to land, their willingness to take lures and their tendency to jump and dodge makes them a favourite among sport fishers. Coho are also caught in large numbers in commercial troll fisheries. Coho were intensively harvested over the last few decades and there have been recent population crashes that prompted severe restrictions in all fisheries.

Chum (Oncorhynchus keta) weighing from 3 to 10 kilograms are the large salmon that spawn in the lower reaches of most coastal streams and rivers in the summer and fall. Spawning chum are readily recognized by the dark horizontal stripe running down their sides, the canine-like teeth of the large males and the checkerboard or calico colouration. Chum salmon are the most widely distributed of the Pacific salmon. In North America, chum are found from Monterey California to east of the Mackenzie River on the Beaufort Sea, and may have made up 50 per cent of the total biomass of all species of Pacific salmon combined.

The species name "keta", which means fish, comes from the Nanai people of Kamchatka in eastern Russia and is an indication of the importance of the species to Aboriginal people around the Pacific Rim. Like the young of pink salmon, the fry of chum salmon do not spend any time in freshwater, leaving immediately for the ocean where they spend from two to six years and range far out into the open ocean. Chum salmon are perhaps the most intensively cultivated of the Pacific salmon. Chum salmon are the poorest jumpers of the Pacific salmon world and waterfalls that do not impede any of the other species can often stop their upstream migration.

Chum
The flesh of chum salmon is relatively low in oil making them ideal for cold smoking, which together with their abundance made the species a food staple for coastal First Nations. In general, chum spawn close to the ocean in small coastal streams. These stream areas are commonly highly affected by habitat damage in the watershed. Activities like logging, agriculture, road and bridge construction and municipal development introduce sediment into streams. Clearing streamsides leads to increased water temperatures. All of these effects are concentrated in the lower sections of coastal rivers and can severely affect chum (and pink) salmon. Chum salmon are typically caught in net fisheries often off river mouths but are also taken in commercial and recreational troll fisheries.
Cutthroat trout (Oncorhynchus clarki) used to be in the genus Salmo or trout, but scientists have concluded that they are more like the Pacific salmon than trout. In British Columbia, sea-run or coastal cutthroat trout are found in most of the streams and lakes of the coastal region and are in the major rivers like the Skeena and Fraser. Coastal cutthroat are anadromous which means they spawn in freshwater but spend part of their lives in the ocean. However, unlike most anadromous species, they remain in and around the estuaries of their natal streams and seldom venture further than a few kilometres into the ocean. Because of this behaviour coastal cutthroat are not caught in ocean fisheries, but they are a favourite of recreational anglers who catch them with flies and spinning lures just off river mouths. Young coastal cutthroat remain in freshwater for as little as one year but most smolt at two years and some never go to sea. Adults spawn in mid to late winter and spawn for the first time at three or four years of age. Cutthroat, like steelhead, can spawn more than once. The average length of adult coastal cutthroat is about 45 centimetres. Young cutthroat are highly adaptable in freshwater and occupy most habitat types from quickly flowing water to sloughs and ponds. In their first year or two, young cutthroat are very difficult to distinguish from young steelhead.

Chinook (Oncorhynchus tshawytscha)

are the largest of the Pacific salmon, weighing from 3 to 50 kilograms, when they return to spawn. Chinook are also called spring salmon because some populations or "stocks" return to their river in the spring. This early appearance means that this species was often the first salmon of the year for many First Nations in British Columbia. Other stocks return during the summer and fall. In large rivers like the Fraser, chinook salmon of different stocks are returning from March to November, with peaks in early July, mid-August and early October. Chinook salmon have varied and complex life histories. The populations of small coastal rivers usually return in the fall while the populations using the headwaters of the tributaries of large rivers like the Fraser and Skeena usually return early in the spring. The young of fall run chinook populations typically swim to the ocean either immediately or after several months subsequent to hatching and emerging from the gravel. The young of spring and summer runs usually spend a year in freshwater.

There can be several different types of chinook salmon with different combinations of run-timing (spring/ summer or summer/fall) and early life history (immediate ocean entry, 90-day entry or entry after one year) in even small coastal rivers. Once in the ocean the young fish spend several weeks to months in the estuary or near the shore. Generally, spring/summer migrating stream-type chinook range further into the ocean than do the early migrating ocean-type fish, which have a more coastal distribution. The fry in headwater populations or in colder northern rivers spend a year in freshwater after emergence.

Chinook, especially larger and older fish are piscivorous, meaning that they eat fish. Because of their large size and presence in coastal waters, chinook are one of the favoured prey of killer whales and recreational and commercial fishers. Chinook are typically fished in "hook and line" fisheries where they chase and bite lures or baited hooks being trolled through the water. Chinook are an unusual Pacific salmon species because the flesh of adults can range in colour from white through pink to deep red. Colour in other species is normally the same in all populations ranging from white in chum to deep red in sockeye.

Pink salmon (Oncorhynchus gorbuscha)

return in prodigious numbers to many rivers in British Columbia. They are the smallest, the youngest at maturity and the most abundant of the Pacific salmon. Spawning pinks generally weigh from 1.5 to 3 kilograms and are always two years of age. Another name for this species is the "humpy". As they mature, male pinks develop large humped-backs, which make them appear larger during territorial battles on spawning grounds. Immediately after they emerge from the gravel in the spring, the young pink fry enter the ocean and after a few days to several months in the estuary and nearshore zone, they move out into the open ocean in large schools. There, pink salmon feed on the small and nearly invisible animals called zooplankton and especially krill, which gives their flesh the bright pink colour for which they are named. In many rivers pink salmon are abundant every year, but in other rivers they appear only every second year. In the Fraser River pinks are abundant in the odd years (2003, 2005, etc.) but are rare in the even years. Pink salmon used to be caught exclusively in gill net and seine net fisheries, but are now also taken by hook and line fisheries.

Sockeye (Oncorhynchus nerka)

were the first species to be caught commercially. They were considered suitable for canning because of their deep red colour and high oil content. Sockeye salmon are slightly larger than pink salmon and generally mature at four or five years of age. Unlike the young of other species that live in flowing water, young sockeye salmon are found in lakes where they feed on zooplankton. However, some sockeye populations behave very much like pink and chum salmon and their young enter the ocean soon after hatching. Scientists think that these "river-type" sockeye are the ancestral form that populated all of the lakes of British Columbia after the end of the last glaciation 14,000 years ago. The Kokanee salmon, which are found in many lakes in British Columbia, are actually land-locked sockeye salmon. In some cases they are found in lakes that have no anadromous sockeye, while in other lakes both types are present. Because the Pacific Ocean offers more types of food to young sockeye, they grow larger and faster than kokanee. Although sockeye and kokanee can mate, the offspring of such pairings are poorly adapted for life either in the lake or the ocean and do not appear to survive.

One of the most remarkable features of sockeye is a phenomenon called "cyclic dominance". In many of the lakes of the Fraser River in particular, sockeye are abundant in one of every four years. Sockeye can mature at ages between two and six years old but in most systems, one age group (usually four-year-old fish) dominates, meaning that most of the offspring produced in any one "brood-year" return to spawn four years later. In many populations, all of the brood-years are about equally abundant, but in many of the populations within the Fraser River there are many more fish in one of the brood-years, the "dominant cycle", than in any of the other three. This cyclic dominance leads to spectacular returns to the Adams River every four years (2002 is in the dominant cycle). Although there are many ideas about why this occurs, nobody knows for sure.

Sockeye appear to be highly adapted to their natal lake. Things like the migration route that the fry must take from the spawning grounds to the lake, the timing of spawning and the time of emergence are all particular to individual lakes. This not only makes each sockeye population special, but also means that sockeye cannot be readily moved from one lake to another with any degree of success. Sockeye are mostly caught in gill and seine net fisheries along migration pathways to their spawning grounds.

Steelhead (Oncorhynchus mykiss)

formerly considered a trout species, is now thought by biologists to be more closely related to Pacific salmon than other trout. Like sockeye, the steelhead has a common freshwater form known as rainbow trout, of which there are six sub-species around the Pacific Rim. Young steelhead are brightly coloured with tints of red, green-yellow, orange and gold. Steelhead live up to nine years and spend between one and three years in freshwater before smolting and entering the ocean. Unlike most of the other Pacific salmon, some individuals live to spawn more than once. Fish that have spawned and return to the ocean are termed "kelts". Up to 20 per cent of spawners, mostly females, are repeat spawners, and individuals can spawn many times. Like chinook and sockeye, there are races of steelhead distinguished by the timing of their spawning migration.

"Winter run" fish enter rivers to spawn from November to May and spawn soon afterward. "Summer run" fish enter freshwater as immature fish between April and October. Spawning occurs from January to May for both races. A population consists of fish of one race or the other, although both races can occur in neighboring rivers. Young steelhead prefer fast flowing water in the mainstream of rivers where there is cool and well oxygenated water. Older juveniles prefer deeper pool habitats with good flow. These habitat preferences make steelhead particularly susceptible to types of habitat disturbance that introduce sediment to fill in pools and removes streamside vegetation that shades the water, keeping it cool. After entering the ocean, steelhead move rapidly offshore and migrate along the coast and out into the Gulf of Alaska. Steelhead are generally not captured in ocean fisheries that exploit species like coho and chinook, which are more oriented to the coast. Summer run steelhead are susceptible to net fisheries for summer run sockeye populations and gill-net fisheries in the Skeena River. Adjustments to fishing gear, locations and time were required to reduce catches of the famed Skeena steelhead. The winter run steelhead of the rivers on eastern Vancouver Island are currently very depressed due to habitat damage from settlement and forest clearing and because of poor survival of smolts after they enter the ocean.