In 2019, SIMRES members joined the Mayne Island Conservancy to map kelp beds around Saturna Island. Mayne Island Conservancy has been mapping the distribution of kelp beds since 2008 by kayak. The data that has been collected shows how kelp has moved, and how it has increased or decreased in its habitat. Our intent is to help increase data collection for a broader understanding of bull kelp in our region.

Bob Bruce, SIMRES Coordinator, Robyn Quaintance, Cedric Torres, Bev and Bill Ramey

This project is lead by Rob Underhill, Biologist, Mayne Island Conservancy. See the most recent information and data here. Read more 


Bull Kelp (Nereocystis luetkeana) is an annual marine seaweed that is common throughout the Gulf Islands. Its range extends from Alaska to California, and it provides important habitat for many kinds of marine life. The plant consists of a long stipe (up to 36 m long), attached to the ocean floor by a holdfast and buoyed at the ocean’s surface by a float, which allows the cluster of smooth blades to obtain light.

Kelp beds look like forests underwater, and create habitat for crustaceans, plankton, snails, juvenile salmon, rockfish, surf smelt, and other marine life. Predators such as harbour seals, sea lions, sea birds, and even orcas hunt around these kelp forests. Kelp swept away by storms can wash up on shore where it is then eaten by decomposers or may sink into deeper water and feed other food webs.

Kelp beds may be negatively impacted by changes in the ocean floor composition or by changes in salinity and temperature of the water. A loss of animals that feed on dead material and remove silt and debris (like sea cucumbers) and an increase in herbivores (like sea urchins) can also have a negative effect.


Grows Quickly – All bull kelp growth occurs from spring to fall, up to half a meter per day. It can grow to 60 meters in ocean waters, but in the protected Salish Sea, bull kelp often reaches 10 metres.

Huge Holdfasts – Bull kelp attaches to rocks below low tide level with holdfasts bigger than your hand, up to 40 centimetres wide.

Gas Floats – The bulbous float at the end of bull kelp is filled with gas containing carbon monoxide.


On many rocky shores around the Southern Gulf Islands, clusters of bull kelp can be seen offshore, growing in the subtidal zone. Kelp beds provide a resting and feeding area for otters, gulls, herons, loons, scoters, grebes, goldeneyes, buffleheads, and other waterfowl. Underwater kelp forests shelter snails, crabs, shrimp, seastars, sea anemones, sea cucumbers, sea squirts, and many other marine creatures. Kelp forests reduce erosion by softening the force of waves against the shoreline. They also serve as a significant carbon sink, sequestering mega-tonnes of CO2 equivalent in the Pacific North West.

Anecdotal evidence is showing a decline in bull kelp in the Salish Sea. Monitoring and measuring change in area of kelp beds over time will enable us to detect changes in abundance of this important marine species.

Experimental research shows that bull kelp ceases to grow with an increase in temperature. The federal government reports that Salish Sea ocean temperatures are increasing at all depths due to climate change effects. We assist researchers from the University of Victoria, University of British Columbia, and Simon Fraser University studying bull kelp by providing them with local information and distribution data. Our work has been used to help assess the use of remote sensing technologies like satellites to map bull kelp. by Leanna Boyer, Mayne Island Conservancy

Mapping takes place during the lowest tides in August. Contact us to volunteer August 14 – 21, 2020.