UVic researchers aim to regrow kelp forests

As kelp forests deplete across coastal waters, UVic researchers are finding innovative ways to regrow and maintain these valuable ecosystems.

Kelp forests are home to an abundance of wildlife—much like forests above ground, these underwater ecosystems provide shelter and feeding grounds for creatures big and small, from orcas and sea lions to snails and worms.

Thousands of species live within a single kelp forest—one study in Norway found 80K organisms were supported by a single stalk of kelp. Similar to coral reefs, these forests are key to keeping marine life thriving.

Kelp is a type of macroalgae that can grow to the size of a 10-storey building. They mostly grow in cold, nutrient-rich, shallow waters along coastlines.

Coastal ecosystems are essential for fighting climate change, with the ability to capture 20 times more carbon than forests on land—kelp, in particular, plays an especially important role in carbon sequestration.

But these forests have declined significantly due to a combination of overfishing, food chain disruptions and climate change.

In the 1800s, the fur trade’s desire for the thick fur of sea otters led to a complete wipeout of the species in the Salish Sea. Without otters to feed on sea urchins, the urchin population exploded—and depleted their food source of choice, kelp. Sea otters have slowly made a comeback over the last couple decades, already showing a positive impact on kelp forest growth.

Warming waters have also been shown to reduce the nitrogen levels in kelp, affecting growth and leading to a less-nutritious food source for species that rely on the algae.

To fight this decline, a team of researchers—led by UVic’s Julia Baum and Sean Rogers of Bamfield Marine Sciences Centre—is working to regrow these forests in the Salish Sea, with a goal to develop a roadmap to recovery.

“It is very ambitious, but the urgency of this problem drives us to commit to these large goals,” says Rogers.

The project is in its second of four years, with researchers now growing kelp in nurseries in Bamfield, focusing on BC's two canopy species—kelp that grow to the ocean’s surface—giant and bull kelp. The kelp grown in Bamfield is then planted in Barkley Sound and Baynes Sound near Hornby Island, where researchers will measure how the kelp fare in these different areas. The hope is that the replanted kelp thrive and eventually grow into established forests.

"If we can get one of these kelp populations to take and potentially be resilient to the conditions that it will face today, and future-proofed for tomorrow, then it’s within the realm of possibility that we will have methods and procedures in place that start kelp forests that eventually become permanent forests that replace the disappearing ones,” said Rogers.

The project combines this research with Indigenous knowledge, with the project’s First Nations liaison Connie Crocker helping to build the team’s connections with multiple coastal nations, in particular the Huu-ay-aht First Nation.

“We believe there’s a huge amount of potential here to do something good for the climate, for biodiversity and for coastal peoples who rely on these ecosystems,” said Baum.