Comox Valley Naturalists Society
Knowing Nature . . .
The Morrison Creek Lamprey
October 27, 2006
In Morrison Creek, a tributary of the Puntledge River in Courtenay, there is a very rare fish that has attracted international attention. About the size of a pencil, this scale-less, silvery fish has a suction-like mouth with sharp teeth, seven pairs of gill pores, and a double dorsal fin. Morrison Creek is the only place on earth where this special creature, the Morrison Creek lamprey, is known to exist.
Lampreys are classified as Agnatha, or jawless fishes, a successful group that has been around about 300 million years. Worldwide there are about 40-45 species of lamprey, mostly in the temperate waters of the northern hemisphere. Many lamprey are non-parasitic and live only in fresh water. Others have a life cycle that, like salmon, involves both marine and freshwater phases. The latter hatch from eggs in fresh water streams, migrate to the ocean, and then return to freshwater streams to spawn and die. Fish with this type of life cycle are called “anadromous”. All anadromous lamprey are parasitic on fishes and marine mammals.
BC is home to four species of lamprey: Pacific lamprey (anadromous, parasitic), River lamprey (anadromous, parasitic), Cowichan Lake lamprey (freshwater, parasitic), and the Western Brook lamprey Lampetra richardsoni (freshwater, non-parasitic). Currently, the Morrison Creek lamprey Lampetra richardsoni var. marifuga is considered a variant of the Western Brook lamprey. Like the Western Brook lamprey, it is a freshwater species. However, it has many distinctive characteristics, including the fact that it is parasitic.
Little is known about this rare variant, and much more research will need to be undertaken to determine whether it actually is a separate species. The Morrison Creek lamprey is of great importance to scientists and evolutionary biologists. In 1999 it was listed as endangered by COSEWIC (Committee on the Status of Endangered Wildlife in Canada). Officially recognized as rare, these creatures are considered at risk of extinction.
The Morrison Creek lamprey has only been found in Morrison Creek. Morrison Creek is unique in that its headwaters are made up of a large complex of wetlands fed by springs. The wetlands act as sponge that stores and slowly releases water through the year. The flow of cold, fresh water has perhaps created special conditions for the Morrison Creek lamprey to evolve since the last ice age. Morrison Creek supports many other species of salmonids, including Pink, Coho, Chinook, Cutthroat, Rainbow and Steelhead trout, Dolly Varden char, and three species of lamprey: Pacific lamprey, Western Brook lamprey, and Morrison Creek lamprey.
Lampreys hatch from eggs laid in a nest of gravel and sand. During this first stage the lamprey larvae, called ammocoetes, live in burrows of soft mud slightly downstream from the nesting site. Ammocoetes are blind, and have no teeth or sucking disc. An “oral hood” overhangs the mouth and is used to filter-feed microscopic plant and animal material. Living from 3-7 years, the ammocoete feeds and grows to a size of 5-10 cm in length.
Eventually, the larvae undergo complete transformation (metamorphosis), somewhat like a tadpole turning into a frog. During metamorphosis, eyes, teeth and a sucking oral disc develop. Gills change, fins enlarge, and internal organs develop. After metamorphosis, anadromous species such as the Pacific Lamprey migrate out to sea where they will spend 1-3 years parasitizing various hosts.
Freshwater forms, such as the Western Brook and Morrison Creek lamprey, will migrate upstream as juvenile adults in October. Soon after metamorphosis, the Western Brook lamprey’s teeth become blunt. As an adult, it does not feed, and is reduced in size compared to its larva. The adult over winters until spring. In the spring, groups of adults excavate nest cavities in a mixture of gravel and sand. The pairs then spawn, the males attaching to the females and fertilizing the eggs as they are released. After spawning, the lampreys die.
The Morrison Creek lamprey retains sharp teeth through its adult stage, and continues to feed by parasitizing other fish. It lives about a year longer than the Western Brook lamprey, and will spawn the following spring. As a juvenile adult it develops distinctive colouration, with a silvery back and white under belly. Prior to spawning, lamprey change into a mature adult stage, becoming sexually mature and ready to reproduce.
Morrison Creek, like many watersheds on Vancouver Island, has been altered by human activity. The area has been logged, and the Inland Island Highway crosses through the creek’s headwaters. There is some leaching into the creek from historic mining activity, and possibly some seepage from the Pigeon Lake landfill. Despite this, much of the stream remains healthy, and has a good buffer of vegetation to help regulate hot summer temperatures. Parts of the creek are protected as conservation areas. The headwaters of Morrison Creek are now part of the Village of Cumberland, and there is a growing pressure to develop this area. There is currently active development in the mid and lower watershed. To ensure the survival of this species, it is important that the watershed, especially the riparian zone, be protected in its entirety.
The Morrison Creek Streamkeepers are volunteers dedicated to preserving this unique watershed, and monitoring the rare Morrison Creek lamprey and many other species. The society actively collects data on the stream, and has undertaken many restoration projects. For more information, check out the Web Site at www.morrisoncreek.org
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