Can commercial fisheries ever be sustainable?

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      A few months ago, I organized a bird-watching trip along the Oregon Coast. The second evening found our group dining at a moderately upscale seafood restaurant where the menu offered this reassuring tidbit: We work directly with our harvesters and purveyors to ensure that our seafood is only acquired from sustainable fisheries. I conjured images of farmed tilapia or perhaps even a wild treat—sardines or squid—seared on the grill.

      The first beer seemed to evaporate, a magical process that hastened the return of our waiter. “The catch of the day,” he recited, “is blue marlin from the Philippines, ono from Hawaii, and petrale sole and rockfish from British Columbia.” Then he was gone, hailed from afar, and we were left to contemplate our gastronomic options.

      My companions returned to their menus. I gulped at my beer and contemplated how to start a conversation that might sour the whole meal. Leaning towards my companions, I whispered, “Those fish aren’t from sustainable fisheries.”

      “Are you sure?”

      “The sole and the snapper are caught by bottom trawlers. I think ono is caught on pelagic long lines.”

      “What about the marlin?” they asked, clinging to hope.

      “Eating marlin is like eating snow leopard.”

      Out of sight, out of mind

      The last time I saw either petrale sole or rockfish (Box 1) they were flopping about the mucous-smeared deck of a bottom trawler. At the time, I was working as an at-sea observer, struggling between debilitating waves of seasickness to tally the grab bag of fish scraped from their bottom lairs. The sole were as brown and flat as old cow patties, the rockfish as orange as Creamsicles.

      What is a bottom trawler (a.k.a. dragger), and why are fish harvested by bottom trawling not even remotely sustainable? A bottom trawler is simply a large fishing vessel that drags a vast, weighted net along the bottom of the ocean with the intention of capturing bottom-dwelling fish. Picture a barefoot child dragging a butterfly net along the bottom of a shallow pond in an attempt to catch tadpoles. Now imagine that same net horribly magnified, capable of catching 11,000 kilograms of fish in one gulp. Bottom trawling is simply dip-netting on a mad scale.

      Bottom trawlers are particularly unsustainable for three reasons: they catch a great deal of fish and thus guarantee over-harvest, they are nonselective in that many nontarget species are unintentionally caught, and they damage habitat by directly contacting the ocean floor.

      One doesn’t require a degree in statistics to recognize the pattern of over-harvest by bottom trawlers. Most notably, bottom trawlers precipitated the collapse of the cod fishery in the northwest Atlantic. The northern stock was harvested by hook and line for centuries, but it took only four decades of bottom trawling to destroy one of the largest sources of wild protein on the planet. Currently estimated at one percent of its 1977 biomass, the northern stock still shows little sign of recovery despite a 16-year fishing moratorium. Globally, the list of stocks that have been fished to collapse by bottom trawlers is incredibly long—and growing.

      Box 1: Rockfish is a general term referring to any species within the genus Sebastes. In British Columbia, 36 species are present, and many of these are commercially harvested and marketed as “Snapper”. Most are also very long lived, some attaining 100+ years. Because of this longevity, and typically low fecundity, they are particularly susceptible to overfishing. The primary method of commercial harvest is bottom trawling. Dan Hershman photo.

      Despite new scanning technology, bottom trawling still results in the catch of nontarget species by the metric tonne. This bycatch, usually eye-bulging dead, are often discarded because either no market exists or the boats have no quota for the species. Petrale sole, to return to our “sustainable” Portland restaurant, is largely a nontarget species in B.C., scooped up incidentally when trawlers attempt to catch other species. The long-lived rockfish are even less sustainable.

      The only reason bottom trawling has persisted into this millennia is that it is entirely out of sight, over the watery horizon and many leagues under the sea. The sea floor of North America’s continental shelf is inaccessible to all but the surest commercial divers and deep-water submersibles. It is also an environment of wonder: corals as bright as bubble gum, vast reefs of glass sponges, and 500-year-old gorgonian sea fans branching like candelabra. Bottom trawlers scrape the sea floor of this biological diversity and plane smooth any structures that protrude above the benthos, a process of habitat destruction that contributes to slow postharvest recovery.

      Fishing with pelagic longlines is almost as ecologically perverse as bottom trawling. A pelagic longliner is a boat that trails a very long fishing line behind it, a line that might exceed 100 kilometres in length and present thousands of baited hooks. The “sustainable” marlin and ono served at the Portland restaurant were probably caught on these hooks. Sadly, these hooks also catch sharks and dolphins, threatened sea turtles, and endangered albatrosses. The pelagic longline fishery is also largely unregulated, a nation-sponsored free-for-all in international waters that can only result in destruction of this common resource. It is roughly estimated that 90 percent of large pelagic fish (tuna, swordfish, marlin, etc.), the top predators in these ecosystems, have already been harvested by pelagic longlines. We’ve pillaged the high seas to stock sushi bars with endangered bluefin tuna, soup pots with seemingly endless shark fins, and chippy shops with battered fillets. Clearly, we need to rethink the very notion of commercial fisheries—can they ever be sustainable?

      Sustainable commercial fisheries?

      If you enjoy your fish with a guilty conscience, you probably have a quick guide to sustainable seafood in your wallet (Box 2). The venerable Monterrey Bay Aquarium initiated the pocket guides as part of their Fish Watch program. The guides were obviously started with best intentions; it makes perfect sense to give people the necessary information to make sustainable choices, and clearly eating certain fish has a greater ecological impact than eating others. For example, Taras Grescoe, in his smart new book, Bottomfeeder (HarperCollins), suggests that top predators should be avoided in favour of abundant forage fish.

      The pocket guides, however, also create confusion. For instance, my guide suggests that B.C. rockfish caught by hook-and-line are okay for occasional consumption, but those caught by bottom trawler are to be avoided. To my knowledge, almost all B.C. rockfish are caught by bottom trawlers and, regardless, only the savviest restaurateur/consumer would be privy to the specifics of how a particular fish, lying on ice or plate, was harvested. Returning to the Portland restaurant, when I asked our waiter if the rockfish was caught by hook and line, he looked at me with much confusion and said it was “ovenbaked”. Further inquiry indicated that sufficient information was simply not available at this restaurant to use the guide effectively.

      Box 2: Produced by the Monterey Bay Aquarium, this particular pocket guide is for those of us living on the West Coast. Although the guides provide much good information, the necessary information is often not available to allow consumers to utilize the guides effectively. For instance, your fishmonger probably would not know if the rockfish was caught via hook and line or bottom trawl (note: it was undoubtedly caught in a bottom trawl). There is also no mention of the fact that the wild Alaska salmon fishery is sustained by billions of hatchery fish, or that Pollock might sustain entire food webs. Clearly, no commercial fishery is without significant ecological costs. Ecofraud is another issue entirely—does the labelling of certain species/stocks/harvest techniques as sustainable simply encourage more ecofraud?

      The pocket guides, by suggesting that there is such a thing as sustainable rockfish, probably do more harm than good for rockfish populations. By opening markets and mouths to a trivial amount of hook-and-line fish, a great flood of trawled fish can race to market, too. And once the fish is off the boat it is impossible to differentiate, a reality that encourages ecofraud by fishermen, wholesalers, or restaurateurs. Recent studies suggest that fully 25 percent of the fish you’ve eaten may not have been the species you thought they were. When it comes to differentiating between populations of the same species or harvest techniques, the likelihood of ecofraud undoubtedly increases. For similar reasons the global community wisely does not allow trade in sustainable ivory because such trade would facilitate trade in black-market ivory.

      Harry Kambolis, the owner of the perpetually trendy C Restaurant in Vancouver, has commented eloquently on a similar dilemma with respect to serving wild B.C. salmon. Given his long-term relationships with B.C. fishermen, Kambolis is able to source wild salmon from stocks that are reasonably healthy. He knows the boats, and he knows where they are fishing. But most of us pushing squeaky buggies around the local grocer don’t have equivalent information, and couldn’t evaluate it if we did. By serving wild B.C. salmon, Kambolis is concerned that he validates consumption of wild B.C. salmon in general. This dilemma has haunted Kambolis to the point where he has contemplated removing wild salmon from C Restaurant’s menu, a difficult decision for a decidedly West Coast establishment.

      Despite Kambolis’s wise hesitation, all five species of commercially harvested wild B.C. salmon are a better choice for the grill than many species for several reasons: there is little bycatch (unlike longlining), direct habitat damage is minimal (unlike bottom trawling), stocks are monitored (unlike pelagic fisheries), and all species are reasonably short-lived (unlike rockfish) and fecund (unlike many sharks). But there are also serious problems with commercial salmon fishing. Much harvesting occurs in the open ocean where it is impossible to differentiate between endangered and healthy stocks. Commercially viable populations are also maintained by huge hatchery operations that release billions and billions of young salmon into the Pacific annually, a process that contaminates the gene pool of wild stocks. And, most importantly, wild salmon are keystone species—any wild salmon that you eat would certainly better feed an orca, sea lion, grizzly bear, bald eagle, or Sitka spruce (which absorb nutrients from fish dragged into forests by other animals).

      At present, a snapshot of the B.C. salmon fishery is complicated; some stocks seem modestly robust, others wallow. Certainly stocks to the south of us, including the historically massive runs of the Columbia and Sacramento Rivers, seem to be heading toward extinction. When it comes to sockeye, arguably the choicest of the wild salmonids, currently suggests that a sockeye from the Nass River is appropriately sustainable, but if the sockeye is from the Fraser or Stikine then it should be avoided. Equipped with this information, I corner the fishmonger at my local grocery store, but she is unsure of the origin of the vibrant fillets. Obviously endpoint consumers of fish, like endpoint consumers of all foodstuffs, would benefit greatly from detailed labelling and rigorous monitoring to prevent ecofraud—the federal government has been woefully inadequate in this regard.

      The future of fisheries is not wild harvest

      Up until the start of the 20th century, commercial hunting was an important industry in North America. Hunters would wander off into wild regions, kill as much game as possible, and then transport the carcasses back to big city markets. It was commercial hunting that almost caused the extinction of bison, extirpated elk from east of the Mississippi, and reduced deer and moose to temporary rarity. Commercial hunting also hammered avian populations: passenger pigeons, whooping cranes, and many other species were pushed toward endangerment or beyond. By now, given the repeated pattern of collapse, it should be obvious even from our removed terrestrial perspective that most marine species/ecosystems are equally incapable of supporting commercial harvest.

      Our notion historically was that the oceans were endlessly bountiful. We believed that even massive harvests would only scratch the surface of marine abundance. Of course, we were naí¯ve and primitive technology limited the potential for overharvest. Now we know that the geographic immensity of the oceans belies the degree of ecological productivity. Vast tracts of the open oceans are biological deserts, areas where photosynthesis is severely limited due to a lack of available nutrients. Despite occupying over 65 percent of the planet’s surface, the total photosynthetic activity of the open ocean approximates that of tropical rainforests, which occupy only 3.3 percent of the planet’s surface. Productive fisheries are concentrated over continental shelves, where the right mix of sunlight and nutrients facilitates photosynthesis.

      This limited productivity, combined with massive harvest capacity, can only result in ecosystem collapse. Not surprisingly, recent statistical analysis suggests that globally almost all fisheries will be commercially extinct within the next few decades due to overfishing. A smarter choice, at least with respect to biodiversity and ecosystem health, would be to abandon the majority of commercial fishing while species diversity and genetic diversity still exists within our oceans. Indeed, given the inevitable reality of crippled ecosystems and endless subsidies, a worthwhile thought experiment is to imagine a future without a commercial fishery. Given our long and complicated history with commercial fishing, and our romantic notions for a bygone era, this is indeed a difficult image to conjure.

      On Canada’s West Coast, a future without commercial fishing would still include a First Nations’ food fishery and a lucrative sport fishery, but these industries combined would only harvest a small percentage of biomass traditionally taken by the commercial fishery. Liberated from the noose of commercial fisheries, marine ecosystems could rebound to historic vibrancy as food webs gradually retangled into a mess of diversity and abundance. The shift away from commercial fisheries would not cause massive financial upheaval in coastal communities because the industry largely self-destructed through overharvest by the mid-1990s—current commercial harvest focuses on the scraps that made it through that bottleneck.

      The transition out of commercial fishing should start with the most ecologically destructive fisheries. Generally that means first halting bottom trawling, which employs relatively few people yet exacts the greatest ecological toll. Because the trawl fishery has shrunk significantly over the past twenty years due to biological necessity, such policy would really just accelerate the eventual demise of the industry. More controversially, the jobs and dollars lost from the trawl fishery could be replaced by modest expansion of the aquaculture sector, an industry based in small coastal communities.

      Aquaculture: the good and the bad

      In B.C., aquaculture has become an increasingly important industry for coastal communities (Box 3). Because it is largely without significant ecological impacts, the culturing of shellfish (mussels, oysters, abalone, etc.) is a no-brainer. Finfish aquaculture, particularly salmon farming, generates over 80 percent of the revenue in this sector and it will therefore continue to be an important component of coastal economies. With salmon farming, there are significant ecological impacts, but these impacts are partially offset by financial benefit. The same cannot be said for most commercial fisheries.

      The primary ecological impacts of salmon farming include the buildup of organic pollution beneath the pens, escape of domesticated salmon into wild ecosystems, and parasite transmission to wild species. These impacts are very real, but often overstated, particularly when compared to the ecological impacts of commercial fishing. A policy of replacing trawl fishing revenue with aquaculture revenue would bring more fish to market, increase rural employment, and contribute more revenue to the provincial economy.

      From a global perspective, the much bigger concern with salmon farming is that salmon are carnivores. To farm salmon, farmers feed them a pellitized mixture of small forage fish (Peruvian anchovies, etc.) and fish scrap mixed together with vegetable protein and meat byproducts. The pellets are much like dog food in composition and appearance (similar mixtures are also fed to chickens and hogs). Currently, because of unavoidable inefficiencies in energy conversion, it takes more than one kilogram of forage fish to produce one kilogram of farmed salmon. This is a huge concern for those of us that advocate for an overall reduction in commercial fishing. However, many producers are now using pellets that contain significantly more vegetable protein and less forage fish, a transition that makes much ecological sense. Through selective breeding of salmon stocks and food engineering, it should be possible to grow salmon (and other finfish) that require only small amounts of fish-based calories, and those fish-based calories could also be farmed, not wild caught.

      Box 3: In 2005, aquaculture contributed $274 million to B.C.’s GDP, compared to only $103 million from all commercial fisheries (over 80 species are commercially harvested in B.C.)*. Modest expansion of aquaculture could replace any revenue lost through an abandonment of the trawl fishery, the most ecologically destructive of B.C.’s fisheries.
      *Figure taken from B.C. Ministry of Environment [pdf]

      Reducing and then eliminating its reliance on commercial fisheries is the most important ecological adjustment the salmon farming industry needs to make. This transition away from fishmeal derived from wild fish is also a looming biological reality because many populations of forage fish have collapsed due to overfishing, a reality that has led to large increases in the cost of fishmeal. Fish farmers are often quick to suggest that fishmeal fisheries are sustainable, but the longterm abundance data for Peruvian anchovies is a rollercoaster of high and low returns, a pattern that can be suggestive of a fishery that could collapse with little notice.

      Over the next decade, while B.C. is getting out of the trawl fishery, the salmon farming industry should work towards eliminating its dependence on wild fisheries. Obviously, global marine ecosystems will only benefit from such a policy shift if all industries that utilize fishmeal are equally accountable (only 10–20 percent of fishmeal is destined for salmon farming). Hopefully, countries that produce fishmeal in quantity will recognize that these forage fish are of more worth in their own ecosystems than in the chicken barns of the world, and they will force necessary change on all of the industries that utilize fishmeal.

      There are other problems with salmon farming beyond the ecological impacts. Norwegian and Dutch companies now own most of the salmon farms in B.C., and there has been much corporate consolidation over the past decade (only five companies now farm salmon in B.C., and only one of these is Canadian owned). Would I prefer to see more small-scale, locally owned salmon farms? Yes, of course. However, foreign ownership is hardly unique to salmon farming, and I’m not sure that, given our trade agreements, we can hold salmon farming to a different standard than forestry or mining or manufacturing.

      Neither does salmon farming provide vast employment. Like farming grain in the prairies, a relatively small number of farmers produce a great deal of product. Currently, the industry in B.C. employs about 1600 people directly, but it's important to note that those jobs are scattered throughout small coastal communities—communities in which even 20 permanent jobs is a big deal.

      Klemtu: a sustainable coastal community

      Klemtu is one of the most remote First Nation communities in B.C. Situated on the central coast somewhere between Bella Coola and Prince Rupert, a Vancouverite can get to Manhattan with less effort. The destination, however, is definitely worth the journey—Klemtu is a vibrant community carved into temperate rainforest, with the Pacific pulsing at its feet and green mountains climbing into the clouds.

      The community is comprised of 450 people of Kitasoo-Xaixais heritage, a people whose ancestral roots are not unlike the roots of the towering cedar, clinging fiercely to the coastal soils for millennia. The town boasts a hundred tidy homes, a modest café, a small high school, a gymnasium for basketball, and an incredible big house for celebrations. Despite the isolation—the lack of road access, the lack of tourist dollars, and the collapse of the wild fishery—there is obvious prosperity in town. The source of that prosperity is salmon farming.

      Historically, like most remote coastal communities, Klemtu depended on commercial fisheries. There was a cannery in town until 1968, and a small processing plant limped into the 1980s. But by the late 1980s, the wild fishery was kaput, and the processing plant was without product. In an attempt to provide some employment, the community, with much foresight, decided to experiment with salmon farming, a fledgling industry in B.C. at the time. Initial successes hinted at the industry’s potential to support the community, and by the mid 1990s the community was looking for a business partner to finance expansion.

      In 1998, the Kitasoo and Marine Harvest, one of the largest companies in finfish aquaculture, signed an agreement to farm salmon. The agreement was smartly done. Rather than simply leasing the farm sites from the community, the agreement also stipulated that 66 percent of the employees on the farms and 95 percent of the employees in the processing plant must be from Klemtu. Additionally, all salmon grown locally must be processed locally, a value-added reality that keeps the processing plant humming for eight months a year. In total, 55 band members are directly employed, typically making $15-$20/hour. The result is a huge payroll for a community the size of Klemtu.

      Box 4: The economy of Klemtu, a remote First Nation community on B.C.’s central coast, is heavily dependent on salmon farming. In total, 55 members of the 450-person community are directly employed in the industry. Lauren Edgar is depicted feeding fish at their Sheep Pass farm site. Cameron MacDonald photo.

      Even after 10 years, the industry is not contentious in Klemtu. According to village elders—individuals with obviously deep connections to the landscape—the environmental impacts seem modest and manageable: they know that the wild fishery collapsed prior to the arrival of the salmon farms, they acknowledge that all goods-producing industries have some impacts, and they realize that aquaculture, if properly done, could sustain their community indefinitely. Provincial and federal governments, after subsidizing commercial fisheries for generations, are justifiably excited by the prospect of a coastal industry that can stand on its own. Klemtu is clearly a potential model of coastal sustainability, a model that could be replicated at select locations along the coast.


      A recent foray into the Omnivore’s Dilemma by Michael Pollen has me again contemplating vegetarianism, a mode of sustenance that I’ve flirted with on occasion. Certainly there are few, if any, wild fish that we can feel good about eating. Eating lower down on the trophic pyramid certainly makes sense (e.g. sardines instead of salmon or swordfish), but we’ve fished many of these lower tier populations to commercial extinction as well. The West Coast sardine fishery of Steinbeck’s California (and B.C.), for example, collapsed to commercial extinction by the 1940s. (Interestingly, after a 50-year hiatus, the sardines are finally back in B.C.’s water in some number. Our response? Resurrect the commercial fishery!)

      From a taste perspective, I might prefer venison to beef, and grouse to chicken, but wild game can only support the very occasional meal. If everyone relied on wild venison to meet the demands of our backyard grill, or wild geese to grace our Christmas tables, then those wild populations would be extinct within the year. Like it or not, commercial hunting and gathering is a lifestyle suited to a bygone era, an era of few mouths and primitive technology. This reality clearly extends into the oceans where more mouths and more affluence are exacting a terrible toll on marine food webs, particularly the top predators. We simply cannot allow our increasingly yuppified taste buds to justify the continued destruction of the top tier of marine food webs.

      Jacques Cousteau, the legendary underwater explorer, once said, “We must learn to plant the sea and herd its animals, using the sea as farmers instead of hunters.” Of course, in 2009, there is still much learning to be done with respect to sustainable finfish aquaculture. The industry needs to continue to improve its practices, and thoughtful environmental advocacy will continue to shape appropriate regulations—perhaps lower pen densities, better site selection, and of course reduced dependence on fishmeal. But to abandon salmon aquaculture, as many environmentalists suggest, would do a disservice to communities like Klemtu, and it would also delay the realization of a truly sustainable aquaculture industry.

      Inspired by Peter Matthiessen’s The Snow Leopard, I once tried to find a snow leopard in the remote Himalayas. Of course, I was unsuccessful; my attempts were meagre and the quarry incredibly rare, one of the rarest mammals on the planet. Competent biologists have spent careers in pursuit of snow leopards with only the blurriest of images and a few hair samples to account for all the hard work. Many finfish are becoming snow leopard-like in their rarity and yet we continue to harvest them with sickening gluttony. And while a buttery piece of raw tuna or crimson fillet of wild sockeye makes a great meal, these species at large in their natural habitat are more wondrous by far.

      Cameron MacDonald is a biology instructor at Langara College.



      Harold Steves

      Mar 30, 2009 at 10:29pm

      There are a lot bof misconceptions in this article.

      Not all commercial salmon species are in decline. There is a surplus of Chum Salmon and lots of Coho for the sports fishery. Commercial Sockeye fisheries have been sustainable in the past and with proper conservation they can be sustainable again, but only if there is enough habitat to support them. Even if fishing stopped today the Sockeye Salmon could never return in the vast numbers of the past because of habitat loss and the new threat of sea lice from aquaculture. That said both Sockeye and Spring Salmon stocks are highly regulated to allow a modest catch while stocks increase. The Native fishery is not the answer as Natives overfish too.

      Thev trawl fishery in BC is relatively recent. The Groundfish Development Authority was established to prevent over fishing. The groundfish fishery has been highly regulated with a quota system since it started and it is definitely not overfished. Because the trawl fishery has been proven to be highly sustainable it has surpassed the salmon fishery as BC's main commercial fishery.

      It is true that the bottom trawl fishery damages habitat and some non targeted species are caught as by-catch. However, ongoing adaptations to the trawl and to fishing methods have reduced both problems. Today by-catch is minimal. Fresh fish markets could be developed for selling the by-catch that remains. In Iceland they eliminated the problem of habitat damage by legislating that the entire fishery is a hook and line fishery.

      None of these problems are valid reasons for not consuming wild salmon or bottomfish; or for supporting farm fish.

      Harold Steves,
      former salmon fisherman and presently a director of the Groundfish Development Authority


      Apr 3, 2009 at 1:35pm

      Shellfish aquaculture is not the environmentally friendly solution that the industry would have us believe. Unfortunately, much of the belief that shellfish farming is benign is not based upon a review of the industry practices and effects. Here are some facts regarding environmental and pollution issues, use of coastal resources and health.

      Environmental Problems

      While few specific scientific studies have yet been conducted in British Columbia to assess the impact of shellfish aquaculture on marine or non-marine organisms or the health of the surrounding ecological systems, there are sufficient scientific studies in other countries to indicate that intensive shellfish operations can have extremely deleterious effects. In particular:

      * Shellfish rafts can reduce water flows by 50% and this can double sedimentation rates1;
      * "All types of oyster culture negatively affect eelgrass" 3. Eelgrass is critical for many species of fish and other marine organisms.
      * "A single raft will produce 16 metric tons of feces" per year2;
      * "Oyster feces adversely affect the fish environment...creating an environment in which no fish live"; "oxygen lack kills many fish"4; Similar effects are created with mussel cultivation and the formation of "mussel mud" and dense algal mats5;
      * Intensive shellfish operations promote the growth of algae that "can cause increased fouling on various substrates, induce green tides near the culture installations, particularly in enclosed bays. 'Green tides' can also cause large decreases in dissolved oxygen"6;
      * Harmful blooms may be created by the deposition of excessive organic matter7; Such blooms consume the available oxygen in water and kill fish.
      * "In small enclosed bays, pollution proceeds very rapidly"8;
      * "Raft biodeposition reduced benthic macrofauna biomass to 5-15% of that of reference sites"9; and "The presence of densely-stocked oyster parks produce anoxic conditions. As a result, macrofaunal abundance decreased by nearly 50%"10;
      * "Within 6 months after the start of culture, brittle stars had disappeared and species originally dominant decreased in number and finally disappeared after 15 months"11.
      * Intensive shellfish operating led to a loss of benthic diversity, anoxia, and massive mollusc mortality12.
      * In Baynes Sound (B.C.), high densities of shellfish operations are "associatied with a decrease in species richness, altered species abundance and distribution, change in community intertidal structure... to one composed primarily of bivalves, and greater accumulations of surface sediment silt and organic matter."13
      * Baynes Sound is also an internationally known important area for migratory birds, yet very little is known about the importance of the intertidal areas for nursing and feeding these birds. 14

      It is evident from these and other studies that intensive shellfish farming is not necessarily the beneficial, sustainable, or even benign industry that its promoters would have the public believe. Since the expansion of the shellfish industry in places like Gorge Harbour (Cortes Island) with hundreds of rafts in an enclosed bay, for instance, residents have observed the almost complete disappearance of starfish, crabs, some species of jellyfish, a marked decrease in the diversity of marine and non-marine species, and unprecedented deteriorations of summer water quality as well as the first appearance of necrotic plankton blooms in living memory. Elsewhere in the world, such blooms have created "dead zones" where marine life could not be supported due to depleted oxygen levels.

      In addition new species of shellfish have been introduced since 1998 as well, including the Galloprovincialis mussel, rated as one of the three absolute worst invasive species of shellfish known in the world15.

      While the reduction in species and deterioration in water quality have not been linked to the expansion of shellfish farming in Gorge Harbour by scientific studies (in fact, there have been no studies examining the suspected links), many residents feel that these developments are far from coincidental. The increased use of netting on rafts and on beaches to exclude competitor species from farm sites is also a probable Harmful Alteration, Disruption, or Destruction (HADD) of fish habitat and bird populations16.


      1. As documented in France and Washington State; see Rosenthal et al. 1988:8, also Carlton et al. 1990; Kaiser 2001:59.
      2. Rates reported for Japan in Rosenthal et al. 1988:9; see also Kaiser 2001:62.
      3. Washington State results in Griffin 1997; see also Carlton et al. 1991; Kelly 2005.
      4. Results from Japan reported by the National Division of Fisheries (1983) Japan.
      5. See Rosenthal et al. 1988:10 for various studies; and Kaiser 2001:61-2 for Sweden.
      6. Rosenthal et al. 1988:8; see also Carlton et al. 1991.
      7. Black 2001:206; see also Rosenthal et al. 1988:8.
      8. National Division of Fisheries 1983.
      9. Cited from Stenton-Dozey et al. 2001 for South Africa.
      10. Kaiser 2001:59 for France, see also p. 62 for Japan.
      11. Rosenthal et al. 1988:10 citing results from Sweden.
      12. Black 2001:210; Sorokin et al. 1999; Bartoli et al 2001; Beadman et al. 2004.
      13. Bendell-Young 2006.
      14. Bendell-Young 2006.
      15. National Geographic, March 2005, p. 114.
      16. Deal 2005:25,29-30.


      Bartoli, M., et al. 2001." Impact of Tapes philippinarum farming on nutrient dynamics and benthic respiration int he Sacca de Goro." Hydrobiologia 455:203-212.

      Beadman, H. 2004. "Changes in species richness with stocking density of marine bivalves." Journal of Applied Ecology 41:464-475.

      Black, K.D. 2001. "Sustainability of aquaculture" In Environmental Impacts of Aquaculture, edited by K. Black. Sheffield Academic Press, CRC Press. Pp. 199-212.

      Bendell-Young, Leah. 2006 "Contrasting the community structure and select geochemical characterstics of three intertidal regions in relation to shellfish farming." Environmental Conservation 33:21-27.

      Carlton, James, G. Ruiz, and R. Everett. 1991. "The structure of benthic estuarine communities associated with dense suspended populations of the introduced Japanese oyster Crassostrea gigas: Years 1 and 2." Report for South Slough National Estuarine Research Reserve, US Department of Commerce, National Ocean Service.

      Deal, Heather. 2005. Sustainable Shellfish. David Suzuki Foundtion: Vancouver.

      Griffin, Kerry. 1997. "Eelgrass ecology and commercial oyster cultivation in Tillamook Bay, Oregon: A literature review and synthesis." Tillamook Bay National Estuary Project.

      Kaiser, M.J., 2001. "Ecological effects of shellfish cultivation." In, Environmental Impacts of Aquaculture, edited by K.D. Black. Sheffield Academic Press, CRC Press. Pp. 51-75.

      Kelly, Jennifer R. 2005. Effects of Non-native Oyster (Crassostrea gigas Thunberg) on Native Eelgrass (Zostera marina L.) in the Strait of Georgia, British Columbia. M.Sc. Thesis, Biology Department, University of Alberta.

      National Division of Fisheries, Institute of Environmental Protection, Japan. 1983 "Pollution" [Anon. translation from Japanese of a NDF brochure].

      National Geographic, March 2005. "100 least wanted species."

      Rosenthal, Harald, Donald Weston, Richard Gowen and Edward Black. 1988. Environmental Impact of Mariculture. International Council for the Exploration of the Sea, Report. Plagade 2-4,1261 Copenhagen K.

      Sorokin, I, et al. 1999. "Need for restricting bivaleve culture in the southern basin of the Lagoon of Venice." Hydrobiologia 400:141-149.

      Stenton-Dozey, Jeanie, Trevor Probyn, and Alistair Busby. 2001. Impact of mussel raft-culture on benthic macrofauna, in situ oxygen uptake, and nutrient fluxed in Saldanha Bay, South Africa.


      Historically shellfish tenures were operated on a small scale with no mechanized equipment (generators or cranes or structures). The operators were generally local people who used boats and were integral parts of their communities. Recently, though, small locally owned leases have given way to large-scale industrial-type operations.

      Industrial-scale shellfish operations produce copious quantities of debris that foul ocean waters and beaches. These operations produce large amounts of debris from styrofoam breakdown, plastic string, plastic trays, plastic tubing (for growing shellfish), netting and other paraphenalia. Noise, and air, and visual pollution from power machinery and structures in residential and recreational areas create additional problems.

      Siting and Conflict with Other Coastal

      Many of the problems generated by the industrial-scale expansion of the shellfish industry since 1998 have been created by the placing of these large operations in environmentally sensitive locations such as enclosed bays and sand beaches. These areas were used and occupied traditionally by fishermen, residents, small shellfish farmers, boaters, and by coastal tourists. The invasion of these traditional areas (already zoned for residential and recreational uses) by industrial shellfish operations has created many conflicts in coastal communities. The lack of realistic siting criteria to better allow for varied and multiple uses of limited coastal resources is a major shortcoming of this unregulated industry.

      There is a fundamental difference in the needs and values of industry and the other users that can only be addressed by separation of uses involving appropriate siting. For Comparison, The Salmon Farm Aquaculture Review Paper, (Chapter 4, "Salmon Farm Siting Criteria states") : "No salmon farms within the line of site up to 1 km from existing residence(s) or recreational property(ies), unless the proposed farm has the support of the residential/recreational owner(s)." There is no comparable policy for shellfish operations. Yet, as Heather Deal states in a Suzuki Foundation Publication on shellfish farming: "Siting shellfish farms appropriately is the most crucial element in planning a successful operation that minimizes the negative social and environmental impact on the community."

      Long mooring lines for extended strings of shellfish rafts are often poorly visible and hang only a few centimenters below the water surface. These constitute significant hazards for small boaters. In Gorge Harbour, despite local protests, the Coast Guard has authorised the placement of strings of rafts across channels between islands, thus blocking former waterway access lanes. Positioning of extensive strings of rafts has also been authorized that potentially interfere with float plane landing lanes. Rebar, netting, and other "structures" on beaches also create hazards for small boaters, swimmers, and beach pedestrians.

      Health Questions

      In a study issued in 2000, B.C. Fisheries identified areas of the B.C. Coast which included some shellfish farms that have "problematic residues of Cd [cadmium] in farmed Pacific oysters"1,2. No routine testing is done of cadmium levels in the B.C. shellfish sold to consumers whereas a number of sites that have been tested exceed internationally recommended concentrations by several times. Nor has any effort been made to site shellfish farms away from locations with high cadmium levels.

      According to Health Canada, cadmium is a toxic metal associated with significant health risks . When consumed, it is deposited in the soft tissue of the body with 50 -70 % accumulating in the liver and kidney. Accumulation of low levels are tolerated by the body, however, higher levels of chronic exposure can lead to kidney dysfunction and possibly breast cancer3. The World Health Organization/FAO Joint Expert Committee on Food Additives and Contaminants considers cadmium a carcinogen.

      In February, 2002 Health Canada released consumption guidelines for regular consumers of BC grown oysters4.

      The maximum monthly intake guidelines for regular consumers of BC grown oysters are as follows:
      Children - about 1 1/2 oysters per month;
      Adults - about 12 oysters per month

      On July 7th, 2006, the Codex Alimentation Commission set new international standards on maximum allowed levels of contaminants including lead and cadmium5. The Codex is a joint food standards body run by two United Nations [the World Health Organization (WHO) and the Food and Agriculture Organization (FAO). The standards apply to food consignments that move in international trade. Maximum limits of cadmium in marine bivalve molluscs and cephalopods set by Codex Standards are:

      “Cadmium should not exceed two milligrams per kilo of marine bivalve molluscs, excluding oysters and scallops, and the same amount in cephalopods such as squids and octopus.”

      It is noted that European Union and Asian markets still have a 1 and 2 mg/kg limit respectively of cadmium for oysters.

      Some B.C. oysters contain cadmium levels up to 4 milligrams per kilo1, several times the maximum amount allowed by Codex specifications, the European Union, and several Asian countries. BC mussels and scallops are also known to have elevated levels of cadmium, although the precise levels for many localities are still being determined.


      1. Kruzynski, George. 2000. "Cadmium in BC farmed oysters: A review of available data, potential sources, research needs and possible mitigation strategies." Canadian Stock Assessment Secretariat Research Document 2000/104. Canadian Fisheries and Oceans Science: Ottawa. ISSN 1480-4883.

      2. Kruzynski, G.M. 2004. "Cadmium in oysters and scallops: The B.C. experience." Toxicology Letters 148(3):159-169.

      3. "Cadmium Exposure and Breast Cancer Risk” is a paper in the Journal of the National Cancer Institute, Vol. 98, No. 12, June 21, 2006 indicating that there is evidence that further study is needed to investigate the probable relationship between cadmium and breast cancer.

      4. "Food Safety Facts on Bivalve Shellfish in British Columbia." Canadian Food Inspection Agency Fact Sheet:

      5. Frances Williams. 2006. Financial Times, 7 July. Also see:


      Cameron J. MacDonald

      Apr 9, 2009 at 2:06pm

      A few comments on the comments:

      Harold Steves wrote “Because the trawl fishery has been proven to be highly sustainable it has surpassed the salmon fishery as BC's main commercial fishery.” The trawl fishery is certainly not larger because it is sustainable, it is larger because the salmon fishery is now much smaller than it was historically for many complicated reasons (overfishing, habitat damage, hatchery fish, climate change, aquaculture, etc.). Given the bycatch and habitat damage, I would argue that bottom-trawling can never be sustainable.

      Harold Steves wrote “In Iceland they eliminated the problem of habitat damage by legislating that the entire fishery is a hook and line fishery.” This is obviously a great idea. Hook-and-line fisheries have impacts, and bycatch, but it is much better technology than bottom-trawling. Transitioning from bottom-trawl to hook-and-line fisheries would be a great first step towards a more sustainable coast.

      Paul wrote “Shellfish aquaculture is not the environmentally friendly solution that the industry would have us believe.” There are undoubtedly impacts with shellfish aquaculture, and you have provided enough references to bury me for a month; however, we must remember that there are also benefits to goods-producing industries, and in the case of shellfish aquaculture, my opinion is that the economic benefits probably outweigh the ecological costs. I will get back to you in a month with a more complete answer.

      Many thanks for the comments,

      Cameron MacDonald
      Vancouver, BC


      Dec 8, 2009 at 11:41am

      The risks to eating BC oysters with high cadmium levels have been verified scientifically (Bendell 2009). All studies of the effect of eating BC oysters that exceed international food safety standards argue that the Health Canada recommendation should be lowered substantially to 3 or 4 oysters per month and that high risk people--lactating women, women w/ low blood iron, smokers, CHILDREN, individuals with renal failure--should monitor cd levels and avoid foods like oysters that carry a high cd load. However, the provincial and federal government, along with the shellfish industry keep this information suppressed and continue to expand oyster raft sites in the richest Cadmium areas in BC, fail to monitor Cd levels, and bury the Health Canada warning in the Canada Food Agency website. In this website Health Canada claims there is no scientific evidence that there are health risks due to eating BC oysters that are high in Cd. Health Canada also does not list the high risk people. Both strategies serve to delude the public into thinking that eating BC oysters is not harmful. There is a preponderance of scientifically credible studies linking eating BC oysters w/ high cadmium levels in the blood and iron. A recent five year study of 60 oyster farmers and their families verifies that their consumption of oysters related positively to high Cd levels in blood and urine."wholesome" for children and all adults; and expansions continue to be approved in the highest Cd level waters in BC. Consumer beware!

      Arlene Carsten

      Dec 11, 2010 at 10:19am

      I think, Mr. MacDocnald, you would do well to really understand what you are talking about. The issue of cadmium in oysters is a very real one. And the long time health effect can be fatal. Take the time to read the citations provided by Paul. CTV even has explored this issue within the past few days and Health Canada is currently updating their guidelines for oyster consumption. Don't put off learning something new. It won't hurt you!


      Mar 12, 2013 at 12:19pm

      why is everyone so hung up on the oyster comment? This articles not about shellfish aquaculture being the end all solution to the problem. It merely suggests it when it states potential alternatives. This article is about the unsustainable fishing methods instituted to maximize yield which is driving many species to extinction. You've proven your point but it should be written as a seperate article, it took me 10 minutes to get to the bottom of this page. If i wanted to read about shellfish aquaculture I would search for an appropriate article. Help us out and author one, I'd like to read about something more relevant to the core of this issue (responsible commercial fishing practices)