Did you know that the oyster grown in BC and most of the rest of the world is an import from Japan? Brought in after overfishing and pollution destroyed populations of our Native oyster? Or that 85 % of all the native oyster reefs in the world have vanished? Or that we have been working on the Native (Olympia) oyster since 2008 and now are starting a more active program? If not read on….
The Native or Olympia oyster (Ostrea lurida) is an integral a part of the Pacific Northwest as are Pacific salmon, yet because of its near annihilation a century ago, it has mostly slipped beneath the threshold of public awareness. Olympia oysters are BC’s only native oyster and were listed under SARA as a species of special concern in 2003 and are Blue listed by the Province of BC. Until the late 1800s, Olympia oysters were highly abundant supporting sustenance and commercial fisheries and occupying thousands of acres of productive, diverse habitat.
Beginning with the California gold rush and then extending north up the coast; over-exploitation, habitat alteration and pollution led to significant declines along the entire coast and near-extirpation in some areas. While remnant populations can still be found today, this species occupies a fraction of its former range in vastly lower numbers and is now functionally extinct through many of the estuaries where it once thrived.
Since the early 1900s, impacts on the Olympia oyster have been dramatically reduced with the collapse and closure of the fisheries and reductions in pollution and habitat alteration, such as improved industrial practices to reduce sedimentation rates in estuaries. Despite this, their populations have not rebounded. This has led to impressive restoration efforts in the United States; despite a serious lack of basic research and knowledge on the species. Restoration efforts are driven by several motivations including the desire to restore important ecosystem services provided by healthy estuaries (e.g. water filtration, shoreline stabilization and creation of important biogenic structure); a desire to restore a native species at risk of extirpation; and the potential of farming a native species of oyster for commercial harvest.
In 2008, the CSR starting working with the Puget Sound Restoration Fund led by our great friend Betsy Peabody and the Nature Conservancy to look for the last “ecologically functional” populations of this species in Nootka Sound. Joined by Fisheries and Oceans Canada staff and aided by local oyster farmer Bob Devault we have made two trips to Nootka Sound to study what maybe some of the last intact reefs.
Local Oyster Farmer, host, guide and all round gentleman, Bob Devault (left) in the RV Atrevida running for a dawn tide (2008) with research crew.
What we found on those trips was pretty amazing, intact reefs of this species, unlike anything any of our “Olympia oyster experts” had ever seen. These are believed to the last few acres of intact reefs – the mountain gorilla of oysters as it were.
For a slideshow about this work narrated by Nature Conservancy’s Senior Marine Scientist Mike Beck follow this link. In addition to biologists, we were joined on our first trip by oyster and food writer Rowan Jacobsen whose essay about the trip can be found here. This essay would later become the inspiration for Rowan’s book the Living Shore. Unfortunately, none of our research partners (or us) have had the funds to continue studying the Nootka Sound populations and we hope that the they will remain intact until we can continue discovering what makes these reefs so special.
Puget Sound Restoration Fund Biologist Brian Allen sets up temporary office in Nootka Sound
In the interim ,we have continued to think a lot about Native Oysters and are emboldened by increased local interest in this species. Read Jeff Nield’s great piece in the Tyee: An Oyster to Fight For. Other groups such as the World Fisheries Trust have started studying remnant (but stable) populations in the Victoria Gorge Waterway (Portage Inlet). As Jeff Nield wrote:
“There is also, among fans of the Oly, a sense that the restoration of the original oyster would have symbolic weight — an acknowledgement of past errors and of a commitment to live more wisely on the landscape that sustains us.”
Shellfish Biologist Joth Davis sampling oysters in Nootka Sound
This year with the completion of the Field Station we are setting out on what we hope will be the start of long term projects on this species. With funding from VIU and a Canadian Wildlife Federation grant through their Endangered Species Fund (Thanks so much!) and partners World Fisheries Trust, we are helping support a new Graduate Student at the CSR, Alicia Donaldson who is studying factors affecting recruitment of Olympia Oysters.
Alicia Donaldson on a hunt for Olympia Oysters in Union Bay, Baynes Sound
Alicia’s thesis project includes: examining the physical tolerances of Native oysters and juveniles; Evaluating settlement substrate preferences; monitoring natural settlement and recruitment in the field and survival of out-planted recruits and; Examining predation pressure on recruits and juveniles.
Published archaeological work indicates that Native oysters were present in Baynes Sound as their shells show up in First Nations shell middens. This summer we have found them throughout the sound but cryptically and in very small numbers.
The next phase of our work (hopefully) is to to enhance monitoring, community stewardship and public and academic awareness of the Olympia oyster in Canada, in a manner that also helps identify the constraints to its recovery and contributes to biological and policy knowledge and tools required to build strategies for the species’ future survival. At the Deep Bay Marine Field Station we want to use aquaculture derived techniques and skills to increase available habitat and use hatchery produced seed to increase effective population numbers and density at our experimental farm in Baynes Sound. By culturing these species we can create a broodstock pool, increasing effective numbers so that they might reproduce at sufficient levels to repopulate the area. This is a simplistic but proven technique that is paying off in other areas.
Armed with scientific collection permits we have been out looking for suitable broodstock. We are restricted to collecting potential broodstock from the Straight of Georgia to maintain genetic integrity and although we found Native oysters in Baynes Sound, they are very few and far between. Fisheries and Oceans had had previously reported this species from Hotham Sound on the Sunshine coast so early one morning recently we loaded the RV Atrevida with summer students and embarked from French Creek for a dawn run across the Strait.
The day was great, the scenery was awesome and while we found lots of Pacific oysters, we had a hard time finding sufficient populations to provide much hatchery broodstock.
Rianna Martindale, hard working Fish-Aqua student doesn’t wait for the tide to drop at the head of Hotham Sound on our oyster hunt and wades out looking for signs of mature Olys.
Ultimately after all this hunting, it was Leo Limberis at Limberis Seafoods in Ladysmith Harbour who informed Alicia about areas on his leases where Oly oysters were recruiting regularly (despite official reports). Ironically the location was where this species was last farmed commercially in BC into the 1930’s. Lesson? Always be aware of the local knowledge and not just the scientists 🙂
Broodstock oysters from Ladysmith Harbour
So now with broodstock from three locations, Alicia is raising larvae and conducting her experiments. At the Field Station with funding assistance from the Environment Canada Habitat Stewardship program (Thanks!) we are operating a small Olympia Oyster restoration hatchery and are raising seed from these broodstock.
Sarah Leduc showing off our little oyster hatchery!
Seed produced from these adults will be stocked to our farm our farm along with shell habitat to attract future next generation larvae. Thereby using our aquaculture techniques and skills to help restore what was once an iconic species. -We’ We’ll provide updates as we go along.
What do you think of this project? Let us know we’d love to hear from you.
For more info check these resources”
McCraw, K.A. 2009. The Olympia oyster, Ostrea lurida Carpenter 1864 along the west coast of North America. Journal of Shellfish Research 28(1): 5-10.