Eat an urchin, save a kelp? Sea urchin harvesting shows promise for restoring and protecting kelp forests
“Deforestation” as a term evokes strong feelings and powerful visuals for many: barren landscapes, the loss of biodiversity, or ecological grief. Primary forest loss both locally and globally has become a widely-recognized problem, yet another type of forest we depend on is rapidly declining, one hidden by high tides. Kelp forests form vital habitats for marine species and coastal communities, but they’re in trouble.
Kelps are a diverse group of seaweed species, a few of which form towering forests that cover one-third of the Earth’s coastlines, mostly off cold high-latitude coasts. Due to the warming climate and its cascading ecological effects, scientists estimate that up to 60% of kelp forests worldwide have either shrunk or disappeared entirely, with the area of lost habitat believed to be tens of millions of hectares. Here in the Salish Sea, some areas have lost up to 74% of their kelp forests in recent years, comprising thousands of hectares. On Vancouver Island, a roughly 150-kilometer stretch of coastline between the northern Gulf Islands and the Campbell River area has completely lost forests of Bull Kelp, an area where they once thrived. With them have gone vital nursery habitat for juvenile salmon, herring, groundfish, and countless other species that depend on kelp forests to complete their life cycle, imperiling fish stocks and the coastal communities that depend on their fisheries.
Two interrelated stressors have driven this loss across the Indigenous territories thought of today as British Columbia: climate warming and an overabundance of grazing sea urchins. Many areas are becoming too warm for forests of Bull Kelp and Giant Kelp to persist, where the only long-term solution is to rapidly transition our economies off of fossil fuels, though some emerging kelp restoration techniques may be able to keep some forests growing in the meantime. In areas that are not yet too warm for kelp to thrive, harvesting sea urchins is a promising pathway to protecting and restoring these marine forests.
Sea urchins are grazers, and a natural part of a healthy kelp forest ecosystem. Like deer overrunning terrestrial forests following the loss of predators like wolves or cougars, urchin populations have exploded since losing predators that normally keep them in check. This started over a century ago, when Sea Otters were hunted to extinction in BC following colonization, since which they’ve only recently begun recovering in some places, after being reintroduced from Alaska. Urchin overabundance went into overdrive just over a decade ago, however, when populations of Sunflower Seastar collapsed, which were their last meaningful predator locally. These large, predatory seastars were wiped out by a devastating new wasting disease, the first outbreak of which correlated to a severe marine heatwave that started in 2014 dubbed “The Blob”. While their juveniles are sometimes found in kelp forests and some adults may survive in cold deepwater refuges, the Sunflower Seastar has not yet recovered in the decade since. Overabundant sea urchins have subsequently destroyed countless hectares of kelp forests, replacing them with mostly-lifeless reefs known as “urchin barrens”. After they’ve grazed away the kelp that once fed them, they can persist in a starved, zombie-like dormant state for years, preventing the kelp forest from recovering.
We’re lucky, however, in that sea urchins are a delicacy prized both locally and globally, and when done right, harvesting them has been shown to effectively simulate their lost predators. Urchin gonads, or roe, have a flavor that’s rich, umami, faintly sweet, and somewhat nutty, and are known most widely by their Japanese name “uni”. They are a traditional seafood for First Nations throughout this coast, known as “x̣íxʷə” in lək̓ʷəŋən, “SQIȾI” in SENĆOŦEN, “xihwu” in Hul’q’umi’num’, or “t̓uc̓up” in Nuu-chah-nulth. The commercial sea urchin fishery in so-called BC is valued at over $14 million annually and employs hundreds of fishers and seafood processors, but has seen declining roe quality and revenues in some parts of the coast, possibly due in part to the decline of kelp forests that normally feed them.
I’ve been privileged to harvest sea urchins both for kelp forest restoration and the commercial dive fishery for the last 2 years, and I believe that it has a beneficial role to play in aiding our imperilled coastal marine ecosystems. Once urchins numbers are reduced below a sufficient threshold, kelp can quickly return to an area if it’s near enough to a remnant forest from which spores can spread. For areas with no remaining kelp to spread spores, such as that coast between the Gulf Islands and Campbell River, kelp grown on rocks in land-based nurseries can be dispersed from the surface following urchin harvesting.
A key lesson has been that not all urchin harvesting is the same, namely, that the intensity and area of a harvest are key to helping kelp forests recover, and regular commercial harvests focused on quality and efficiency may leave too many urchins behind for kelp to recover. Seafood harvesting alone is also insufficient for restoring urchin barrens, where their starved condition often renders them unfit for consumption, leaving huge swaths of lost habitat off the table for this approach. Creative solutions are needed for urchins in these areas, and a growing body of research on non-seafood products shows promise for harvesting barren-starved urchins.
I’m keen to see targeted urchin harvests for kelp forest restoration grow and scale on this coast, as there have mostly been small pilot projects to date. We’re still in the early days of linking urchin harvesting with restoration activities, but can look to other countries like Australia, where harvesters, processors, scientists, resource managers, and First Nations rights holders have worked together to conserve and restore large areas of kelp. As someone with feet planted both in marine science and urchin harvesting, I’m excited for what the future holds here in so-called BC, and believe that if we work together, we can protect and restore these vital habitats while advancing a sustainable fishery for coastal communities.
About the author
Clay Steell is the Founder & Principal of Blue Futures Kelp, which grew out of a mission to restore kelp forests lost to climate change and imbalanced ocean ecosystems. Clay has spent the last five years researching how to restore forests of Bull Kelp and Giant Kelp across what's thought of today as southern British Columbia, working with partners from First Nations, academia, and industry. He holds an MSc in biology and is certified as a scientific and occupational SCUBA diver. Learn more at bluefutureskelp.ca.
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