A chum salmon arriving at the spillway into the lagoon. Photo:Will Husby
Chum is the largest salmon species that spawns on Bowen Island. Individual fish are typically in the 4 to 6 kg range as returning adults. Adult chum spend about four years fattening up at sea before returning to the stream where they were born to mate and die. Wildlife Club volunteers operate the Terminal Creek salmon hatchery and monitor the health of Bowen’s salmon bearing creeks and riparian areas.
Around Remembrance Day, many Bowen Islanders walk down to the spillway at the Causeway that separates the Lagoon from Kwilákm to watch the arrival and spawning of the chum in the gravel spawning beds just inside the Lagoon.
Photo: Will Husby
The viewing is easy. The arriving salmon wait for the incoming tide in the ocean waters near the causeway. At high tide they swim up the fish ladder or up the spillway under the bridge.
Spawning chum viewed from the Causeway. Photo: Will Husby
Many gather over the gravel bar constructed by Bowen’s Fish and Wildlife club just upstream of the bridge, where their spawning activities can be easily seen. Female chum have normal shaped jaws.
Photo: Bob Turner
Watch how they flick their tails to dig shallow nests called redds in the coarse gravel.
Look for male chum. They have big jaws with large teeth. They use them to fight other males for chances to mate with the females.
Each female chum will have laid thousands of eggs. And like all Pacific salmon, chum males and females die soon after they mate.
The abundant eggs and salmon (both dead and alive) attract all sizes of predators and scavengers.
Watch robin-sized dippers as they jump into the fast flowing sections of the spillway and gravel bar to snatch stray salmon eggs for a nutritious meal. Photo:Will HusbyPhoto: Will Husby
Watch for harbour seals in Kwilákm close to the Causeway. They come to intercept the salmon before they reach their spawning bed. Sometimes they will swim right into the lagoon to grab spawning salmon on the gravel bar.
River Otter. Photo: Jon David Nelson licensed under Creative Commons BY-NC-SA 2.0.
Also look for fast swimming river otters who may come to dine on spawning chum.
Immature bald eagle. Eagles come to feast on the dead salmon. Photo:Will HusbyMany species of gull will be attracted to the easy pickings of dead and dying salmon. Photo: Will Husby
Chum Salmon Fry Release
Bowen’s population of wild spawning chum salmon is supplemented by hatchery-reared fish raised by volunteers in the Bowen Fish and Wildlife Club working with the Department of Fisheries and Oceans Terminal Creek Hatchery (see Terminal Creek Fish Hatchery).
The area nearby to the Lagoon showing the estimated shoreline of the tidal inlet at low tide before construction of the Causeway and formation of the Lagoon. Map: Bob Turner / Will Husby
This estimate is based on historic photographs (see the photos in this story) which show the pre-Lagoon shoreline at various tide levels.
At a high tide, the shore line of the pre-Lagoon inlet would have been similar to the current shoreline of the Lagoon.
An early 1900s bridge across the tidal inlet at the present location of the Causeway, connected the Union Steamship Hotel grounds to Snug Cove harbour. Photo: Courtesy of Bowen Island Museum and Archives.Photo: Courtesy of Bowen Island Museum and Archives.
A later bridge across the tidal inlet at the present location of the Causeway, looking north. The large gravel bar on the north side greatly narrowed the mouth of the inlet and made it an obvious place for the bridge.
A coloured photograph of a vehicle bridge across the tidal inlet at the present location of the Causeway, showing the sand and gravel bar that narrowed the mouth of the inlet. Note the heavily logged forests along the north shore of Deep Bay. Photo: Courtesy of Bowen Island Museum and Archives.
In fact, the tidal inlet looked similar to the shores of Kwilákm near the Causeway today – a shallow tidal inlet that largely dried at very low tides, exposing extensive sand flats deposited by Terminal Creek. A gravel bar near the mouth of this small inlet created a narrows that was the chosen site for several generations of bridges that preceded construction of the Causeway at the same location.
During a very high tide, the inlet would look much like the Lagoon today, but during lower tides, beaches and tidal flats would be exposed. The damming Terminal Creek by the Causeway changed the tidal inlet to the brackish water (mixed salty and fresh) pond we now call the Lagoon.
A view from the top of Bridal Veil Falls looking east down the tidal inlet (future Lagoon) towards the Bay.
The photo is taken during a low tide, the inlet is largely empty of ocean water, and Terminal Creek flows across a gravel flats to the sea in what is now the Lagoon. Note the two bridges that crossed the inlet. Photo:Courtesy of Bowen Island Museum and Archives.
If you snorkel in the Lagoon, or peer into its shallows, you are likely to see small schools of tiny fish. These are three-spined stickleback, fish that are unusual in just about every way.
Photo: Will Husby
Stickleback are unusual in design; are small (3 to 4 cm) slender fish with three prominent spines along their backs. These spines give the fish its name and can be locked upright in position, a defense against a predator trying to swallow it.
Stickleback are at home both in salt and freshwater; this is a rare feat for fish. This feature allows stickleback to swim back and forth between the Lagoon and the ocean. Stickleback can feed in both the Lagoon and the nearby Bay, but return to the Lagoon during the spring breeding season.
What makes stickleback most unusual is their breeding behavior. The male will stake out an area of the Lagoon, protect it from other males, and then construct a nest in a shallow depression. The males collect small bits of debris, glue them together with a secretion, building a tunnel-like nest.
Illustration by Alexander Francis Lydonis in the Public Domain
The male then attracts the attention of a female, enticing her to enter the nest and lay eggs. After he has fertilized the eggs, the female is shooed away. The male guards the nest until the eggs hatch, and then continues to guard the young fry. All in all, quite extraordinary.
Bowen’s Canada geese are relative newcomers to the west coast, and they have a different history than the flocks of Canada geese we see high overhead on spring and fall migration. Our resident geese are the products of a 1970s experiment aimed to provide hunting opportunities and enhance wildlife viewing and by intentionally introducing juvenile Canada geese from eastern Canada to Metro Vancouver. The plan was that hunters would check goose population growth.
Canada goose eating grass beside the lagoon. Photo: Will Husby
The geese headed to urban areas where they found few predators. Municipal restrictions on firearm discharge ruled out hunting. Lacking a goose family to teach them the traditional migratory habit (and with fine edibles close to hand) the newcomers had no reason to move on. Vancouver’s wild migratory geese became urban residential geese and expanded their territory to include Bowen Island.
The newcomers liked the plentiful food in their new home. Lawns, parks, and golf courses offered grazing opportunities through winter months, a time when wild pickings can be lean.
Bowen’s Canada geese have chosen to live among Deep Bay’s finest waterfront real estate. Acres of mowed, grassy lawns provide an endless supply of tender, young, shoots to feast on. The Cove has clear sightlines and easy access to water for a quick escape. Dense human occupation discourages most predators. Frequent handouts of food are an attractive bonus.
Photo: Mary Le Patourel
Canada geese pair up by their third year; mate for life; lay an average of five eggs each spring; and can live in the wild for over 20 years. Each summer, adult geese shed their feathers to make way for new growth. During the moult, both adults and young depend on food resources within walking distance of the breeding area.
The Canada goose’s habit of mixing gosling from several families into large groups (super broods) under the care of a few sentinel adults provides both safety to goslings and an advantage to adults. Researchers believe eagles, ravens, and crows, who commonly prey on goslings, find an individual gosling in a tightly moving group harder to pick off one isolated young bird.
Photo: Mary Le Patourel
Large families may provide benefits for goslings and parents alike. Large goose families tend to dominate smaller families during social interactions; super broods secure access to the best food so their goslings grow faster.
With a year-round supply of food, and very few predators, Bowen’s population of Canada geese appears to grow every year. Large groups displace other native waterfowl, reducing the availability of food, shelter, and nesting sites. Canada geese frequently overgraze natural habitats, particularly along fresh and brackish water shorelines, which directly reduces plant species diversity. Vegetation loss along shorelines results in increased erosion and sedimentation of water bodies, as soil and other particulates are suspended in the water column.
The humane way to limit flock growth and stabilize goose populations is to keep eggs from hatching by treating them with corn oil, a process known as “addling.” Addling can be done only with a permit from the Canadian Wildlife Service.
When you see a flock of geese grazing, give them space. Under the BC Wildlife Act it is illegal to harass wildlife. Unleashed dogs must not be allowed near geese. Something we can all do is to NOT offer food to the geese. Supplemental feeding by humans can contribute to geese being able to lay more than one clutch per season. Managing growing populations of non-migrating Canada goose is a challenge.
There were no beavers on Bowen Island/Nex̱wlélex̱m when my young family and I moved here in the early spring of 1988. Beavers first appeared in the early 1990s in the Lagoon and soon moved upstream all the way to Killarney Lake. Long-time residents told me there had been muskrats, which had been trapped out in the first half of the 20th century, but told no similar stories of beaver. Now beavers, their dams, lodges, and cut vegetation can be found in many places, mostly but not only in the Killarney-Terminal watershed.
Recorded distribution of Beavers on Bowen Island. Map: Alan Whitehead/Will Husby
Were beavers present on Bowen Island before the early 1990s? Where did they come from? How did they get here? Are they here to stay? My hypothetical answers below are based on the stories I’ve heard, reviews of beaver ecology, and personal observations on and off Bowen over the years.
Kwilákm is the beavers’ main doorway to the island. We know from personal observation that their arrival in the 1990s was on the east side of Bowen, via Kwilákm and the Lagoon. It is likely that they came from the Fraser Valley lowlands, where beaver populations have been increasing over the past century as a result of the decline in trapping, construction of drainage canals, and other changing land uses.
Beavers are strong swimmers. Although they live in fresh and brackish water, they are known to cross significant spans of saltwater; this happens particularly when the young adults are dispersing away from their birth habitat after their second year. Beavers would have no trouble navigating the waters between the mouth of the Fraser River and Bowen Island and beyond.
Presumably, they are attracted to freshwaters that smell of marsh vegetation and organic sediment. I can picture a beaver swimming out of the Fraser River’s North Arm into the mouth of Howe Sound, passing by the mouths of smaller streams that, though freshwater, do not smell of wetland and lake and are not explored. Likely, the first attractive outflow the beaver would come to would be the freshwater plume from the Lagoon, tasting and smelling like a possible future home.
Initially, based on the old-timers’ accounts, I thought that beavers had not been present on Bowen until the last decade of the 20th century. After all, mature coniferous forest in a mountainous setting wrinkled with narrow- bottomed V-shaped valleys and few permanent streams, does not normally provide ideal beaver habitat.
Once I started to explore the island, however, I discovered what appeared to be the remains of three ancient beaver dams at the marsh known as Mud Lake, above Killarney Lake on the west side of Collins Mountain. The uppermost dam retains water in Mud Lake itself; the next two create the ponds at the headwaters of upper Honeymoon Creek that flows into Honeymoon Lake.
Growing along the crest of each dam is a line of several large red cedar trees. Their large diameter, up to about 18 inches, suggests that the dams have been there since well before the early 1990s. Photo: Alan Whitehead
Mud Lake is a saddle wetland perched on the divide between two small watersheds; it drains in two directions: normally to Honeymoon Creek and, during highest water levels, to upper Killarney Creek and the lake.
Currently, descendants of the latest wave of immigrant beavers have again taken up residence at Mud Lake, where a lodge and beaver-cut trees can also be seen. As before, it is likely that the dispersing beavers arrived from Killarney Lake, following the scent of marshy water. Other ancient beaver dams, or their remains, may have been present elsewhere on Bowen. However, all the island’s main lakes, which are the obvious places to look for beaver history, have been dammed for human water supply; the higher water levels and natural decomposition would have erased any traces of dams or lodges or beaver-cut stumps.
A large wetland created by beavers along Killarney Creek in Crippen Park. Note the dead trees. Ponded waters killed the forest, allowing sun-loving marsh plants to thrive here. Photo: Will Husby
Are the beavers now here to stay? Yes, but not in large numbers and only in the best habitats, and only where they don’t conflict with humans. Interestingly, where water and topography allow, beaver activity can actually create just the environment that favours the growth of wetland and deciduous riparian vegetation they need to thrive.
But those conditions aren’t widespread. Judging from the large girth of some of the cedars that have been gnawed as a source of bark for food, life may not be easy for the young beavers that, during their dispersal, try out more remote locations. In these areas, the preferred forage plants are scarce and the streams and wetlands tend to go dry during the late summer and early fall, leaving beaver dams useless, their dens exposed.
Snow on one of Killarney Lake’s beaver lodges in January 2021. Other lodges with underwater entrances are excavated into the lake bank. Photo: Alan WhiteheadBeaver bank burrow
I’ve seen beaver-gnawed trees in other, smaller watersheds on the east and west sides of Bowen, but all these sites have been abandoned, likely because the stream or wetland went dry during the summer.
In the prime habitats, however, such as Crippen Regional Park, the municipal park at Grafton Lake, Headwaters Park, and possibly other existing and future protected areas that have suitable conditions and minimal human interference, beavers will likely endure. All they will need is an abundance of year-round food and watery shelter habitat, plus a connection to Howe Sound for dispersal and recruitment of mates to maintain genetic diversity.
A beaver-cut holly tree at Grafton Lake. Beavers feed on the inner bark, green twigs and shoots. Photo: Alan Whitehead
Please feel free to help us fill the gaps in Bowen Island’s natural history. To contribute any additional information that you may have on the history of beavers and their present distribution on Bowen Island, contact us at BowenNatureClub@gmail.com.
Alan Whitehead is a long-time resident of Bowen Island, a professional biologist, and the Volunteer Warden of the Ecological Reserve on Mt. Apodaca.
When you look beneath the surface of the Lagoon, you can see an underwater forest of pondweeds and other aquatic plants swaying gently in the current. As well, the waters are murky with the growth of several species of freshwater phytoplankton adapted to thrive in the warm nutrient soup that is the lagoon waters. Photo: Bob Turner
In summer, the Lagoon’s shallow water is warmed by the sun. The abundant nutrients in the water provide ideal growing conditions for a variety of aquatic plants.
If the sun is shining directly on the water, look closely and you can see clouds of tiny bubbles gathered around the Lagoon’s plants. You are seeing photosynthesis in action. All plants take in carbon dioxide, combine sunlight with carbon dioxide and water and then to synthesize their food. Plants use the carbon dioxide to fuel their own growth and release oxygen (split from the water) in the form of tiny bubbles.
This profusion of aquatic vegetation provides abundant food and shelter—ideal habitat for bacteria, snails, crayfish, water boatmen bugs, and other aquatic insects which in turn attract predator insects such as the damselfly and dragonfly nymphs, predacious diving beetles, and water scorpions. And this habitat is also ideal for fish such as sticklebacks, salmon fry, and shiner perch.
The abundance of these small fry attract larger herbivores and predators. Dabbling ducks such as mallards come to feed on the water plants.
On the Lagoon’s surface, mallard ducks, who are mostly vegetarian, filter out small seeds and other particles using the tip of their bill tip to draw surface water in, then pass it through a lattice of fine combs along each side of their jaw to separate the good stuff. Photo: Cathy RobertsonTo reach submerged vegetation, mallards extend their reach by foraging head-down.Photo: Judith McBride
Mergansers, grebes, and great blue herons hunt the small creatures that hide in the aquatic plant jungle.
A hooded merganser with a sculpin it caught in the Lagoon. Photo: Will Husby
The Lagoon was once a narrow inlet of the ocean where at low tide Terminal Creek flowed across tidal flats. At high tide, the inlet was filled by the ocean.
Construction of the Causeway in the 1920s dammed the flow of Terminal Creek, forming the freshwater/brackishwater lagoon.
Conditions in the Lagoon change with the seasons. In fall, winter and spring, heavy precipitation sends vast amounts of cold freshwater gushing over Bridal Veil Falls just upstream of the Lagoon. In these seasons, the Lagoon is full of cold oxygenated water that flows quickly into the Bay. Even when high tides allow seawater to flow into the Lagoon under the Causeway bridge, it is quickly flushed back into the bay by the strong freshwater flow from Terminal Creek.
In winter, freshwater from Terminal Creek gushing out the Causeway spillway in winter flushes out any sea water that enters the Lagoon at high tide. Photo:Will Husby
In effect, in these seasons, the Lagoon is a small freshwater lake. Conditions at this time of year are excellent for juvenile salmon, stickleback, cutthroat trout, crayfish and a vast array of aquatic insects.
In summer, there is little to no rain and Terminal Creek becomes a trickle, releasing small amounts of cool, oxygenated freshwater into the Lagoon. Saltwater that flows into the lagoon from the Bay at high tide remains in the lagoon and mixes with the creek’s freshwater. As a result, in summer, the Lagoon is a brackish water lake whose waters drain leisurely into the Bay. Many aquatic creatures find it difficult to live in brackish water, however crayfish and some aquatic insects thrive in these mildly salty waters.
Juvenile salmon like these coho take advantage of the lagoon’s brackish water as a half-way house to adjust their physiology from being adapted to living in freshwater to being able to live in salt water, before they head out to sea. Photo:Will Husby
The year-round abundance of aquatic plants and small aquatic creatures attract mallard, swans, mergansers, grebes and Canada geese.
A pie-billed Grebe feasting on a small crayfish. Photo: Will Husby
