meadows are one of the most important biological features of the Gorge. These plants grow in soft sediment, and provide sheltered habitat for fish such as juvenile Pacific salmon and cutthroat trout. Decaying eelgrass leaves and other plant matter, called detritus, nourishes a complex food web of other animals, mostly invertebrates. The rhizomes (branching roots) of eelgrass are important for trapping sediments and reducing shoreline erosion.
Another important plant community in the Gorge is the kelp
beds. Kelp includes several species of large brown algae that anchor to rocky substrates with a holdfast, and have large leaf-like blades for capturing sunlight. Some kelp species (e.g. bull kelp or Nereocystis luetkeana
) have blades that float near the surface of the water. In the lower Gorge (below the narrows) kelp beds cover about 60% of the subtidal surface. The main species present in this area is Laminaria saccharina
. Kelp grows in areas where currents or upwelling supply abundant nutrients. It provides important habitat and/or a food source for fish and marine invertebrates. In many areas, kelp beds help attenuate the effects of wave action on the shoreline.
Green algae, primarily sea lettuce
), are common among the eelgrass beds in the Gorge, and in shallow intertidal areas. Filamentous red algae (primarily Polysiphonia
) are most dense in the high current areas of the Gorge.
Intertidal gravel bars in the Gorge have significant shell deposits, indicating the presence of littleneck and butter clams. Mussels (Mytilus
) are abundant in the high current areas of the Gorge, especially at the Narrows.
The native Olympia oyster
) is another significant species found in the Gorge and Portage Inlet. Historically, this oyster was an important food source for First Nations and non-aboriginal residents. Due to over-harvesting, pollution and predation from invasive species, large Olympia oyster beds are now rare on the west coast of North America. Olympia oysters are food for animals such as snails, limpets, sea stars and birds including white-winged scoters, black scoters and the greater scaup. Since oysters are filter feeders, they help to clear the water of sediment and organic matter.
Rocky subtidal benthic communities are groups of plants and animals that inhabit rocky areas of the ocean floor in the subtidal zone. They include aggregations of sedentary sponges, tunicates, bryozoans and cnidarians (e.g. anemones). Mussels, sea urchins, gastropods (e.g. snails and limpets), and crabs are also common. Some of the largest such communities in the CRD harbours thrive in the high current areas of Gorge, where tidal currents sweep through with a steady supply of food (e.g. plankton, detritus) and oxygen.
Brittle stars are echinoderms, close relatives of sea stars. The species found in the lower Gorge (Amphiodia urtica
), has been observed in densities of several hundred per half a square meter, buried in mud with only the tips of their flexible arms exposed.
used to spawn regularly in the Upper Gorge, primarily in the eelgrass beds. This has not been observed since the 1970s, but schools of herring still enter the Gorge annually. People often jig for herring from the Craigflower Bridge and Selkirk Trestle in the early spring.
Two streams that flow into Portage Inlet (Craigflower
creeks) support spawning populations of coho and chum salmon, as well as cutthroat trout
. Although the runs are much reduced from historic times, there are ongoing efforts to restore these populations. Juvenile fish shelter in eelgrass beds in the Gorge and Portage Inlet.
Gorge Waterway Birds
The Gorge Waterway connects Victoria Harbour with Portage Inlet, one of the areas most heavily used by birds in the urban Victoria harbours. The entire inlet is part of a federally designated Migratory Bird Sanctuary. The upper Gorge, between Craigflower and Gorge bridges, supports numerous populations of resident and migratory birds. Species observed include cormorants, mallards, American widgeon, Canada geese, and diving ducks (e.g. bufflehead, greater scaup and canvasback). In the winter, diving ducks, mergansers and coots are the most common group of birds seen in the Gorge, whereas in summer and fall swans, geese and dabbling ducks predominate. The Gorge and Portage Inlet are two of the most important feeding areas in the CRD harbours for the double-crested cormorant, a red-listed (endangered) species.
More information about the relative abundance of different birds throughout the seasons in the Gorge, as observed in 1997-1999, is available here