Cross is leading a $1-million pilot study, now in its third year, exploring the viability of growing kelp alongside fish farms. The idea behind the study, which is being done with the BC Salmon Farmers Association: excess nutrients from a fish farm could act as a fertilizer for kelp, supercharging the plant’s growth. In turn, kelp could provide additional revenue while absorbing much of a farm’s waste, not to mention sucking up planet-warming carbon dioxide.
In 2015, Cross’s team hung ropes seeded with baby kelp from buoys at a fish farm near Tofino and measured the growth rates. Seedlings planted closest to the fish pens grew almost 50 per cent faster than those planted further afield. Last year, the researchers expanded their scope, installing kelp-seeded lines at 30 fish farms around Vancouver Island, to get a better sense of growth rates in different oceanic conditions. (At the best sites, kelp seedlings grew nearly four metres in just three months.)
The next step in Cross’s research program is to estimate how much kelp could be grown within the 160-odd fish farming tenures in B.C. and the potential economic yield. The value of the kelp depends on its end market and how it’s processed, he says. But the modest startup cost—“basically, some rope, anchors and a boat”—means it could provide a low-barrier economic opportunity for local communities. “You and I could never afford to start a fish farm—it’s millions of dollars,” Cross explains. “But you and I could put in $5,000 each and become kelp farmers.”
Northern Vancouver Island’s Kwakiutl First Nation has been working closely with Cross—one of the test sites is within its traditional territory—and is keen to see the study results. Tom Child, lands and resource manager with the Kwakiutl, notes that coastal First Nations have a long history with aquaculture, from building clam gardens to harvesting wild kelp covered with nutrient-rich herring roe. “Dr. Cross’s method of aquaculture fits within the Kwakiutl paradigm of sustainability—no unnatural inputs—on a scale that makes sense for us,” he says.
The Kwakiutl are developing a multi-species aquaculture strategy for their community. Their plan, Child says, is to create vertical underwater gardens, with a variety of shellfish, seaweeds and edible plants. “We’re happy with the planning stages so far,” he adds, “and we’re looking forward to the rubber hitting the road on this kelp project.”
Down the coast, Druehl is getting more visitors to his Bamfield home these days. “We bring people in, and we show them how to farm,” he says. Druehl has consulted for kelp restoration projects in Puget Sound and Esquimalt, and for seaweed farming startups in Alaska and California. But for now, at least, his kelp farm remains the only one in B.C.