Oysters F.A.Q.s

Mon, 2010/03/15 - 2:25am — admin
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What is Aquaculture?

Fisheries Act Sec. 1: "aquaculture" means the growing and cultivation of aquatic plants, as defined in section 12, or fish, for commercial purposes, in any water environment or in human made containers of water, and includes the growing and cultivation of shellfish on, in or under the foreshore or in water.

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What oyster species are grown in B.C.?

The most commonly grown oyster in BC, both in farming and in wild populations, is the Pacific oyster (Crassostrea gigas). Other farmed species include the Kumamoto oyster (Crassostrea sikamea), the Eastern or American oyster (Crassostrea virginica) and the European flat oyster (Ostrea edulis). The native or Olympia oyster (Ostrea conchaphila) is a small, slow-growing species that is also present in wild populations, especially on the west coast of Vancouver Island.

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Where is oyster farming happening in B.C.?

There are over 300 companies on about 490 shellfish tenure sites in BC, most of which produce oysters. The main oyster areas are on east and west coasts of Vancouver Island (Baynes Sound, Gulf Islands, Barkley, Clayoquot and Nootka Sounds) and on the Mainland (Sunshine Coast, Malaspina Inlet area, Desolation Sound). There are a few shellfish farms on the Central and North Coasts of BC, as well.

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When selecting a site for oyster farming, what should I look for?

When considering a location for an oyster farm, the prospective farmer should be aware that many factors contribute to an appropriate choice, including environmental or biophysical criteria, and social and economic or suitability criteria.
A handy model, the Site Capability Index or SDI, combines these criteria in a numerical index, between 0 and 1. Most of the BC coast has been surveyed for Shellfish Capability for the Pacific Oyster (see ftp://ftp.gis.luco.gov.bc.ca/pub/coastal/sf_capability/ for detailed surveys).

Environmental Parameters for Oyster Capability
      Note:  the parameters listed below can be used to determine whether a site is capable of sustaining a commercial oyster farm. The order in which the factors are presented doesn’t imply a ranking of priority; any one or combination of these factors could be limiting to the site’s capability.

  1. Water temperature: (summer/winter extremes, for bottom and off-bottom culture). Range: 8-34° C; Optimum: 15-18°. C
  2. Food supply: (phytoplankton abundance or chlorophyll concentration: bottom and off-bottom culture). Range: 1-55.0 ug/L Chlorophyll; Optimum: 12+.
  3. Wave height from fetch: (wave height re: distance and direction for wave and wind action; for bottom and off-bottom culture). Optimum: wave ht <0.5m or fetch <1 nm in winds >60 km/h.
  4. Growout position: re: tidal height or water depth: (bottom: Range 0-4m, Optimum 1-2m; and off-bottom culture: Range: 0 to -10m; Optimum: 0 to -5m. To reduce impact on bottom, locate so there is >10m below gear to bottom at low tide).
  5. Suspended sediments: at high levels (> 100 mg/L PIM [Particulate Inorganic Matter]) may affect feeding (short-term) and meat condition or survival (long-term).
  6. Water movement: tidal or wind-driven currents affecting food supply, biodeposition, security of infrastructure. Range: 0.05 -1.0 m/sec; Optimum: 0.1-0.5 m/sec.
  7. Prevalence of disease: Optimum: not present.
  8. Fouling organisms: Range: incidental, minor coverage to heavy shell overgrowth (latter will affect growth and meat condition). Optimum: not present.
  9. Predators: various for seed and adult stages, including sea stars, crabs, flatworms, pile perch, etc. Optimum: not present.
  10. Salinity: (summer/winter extremes, for bottom or beach culture and off-bottom or deepwater culture). Range: 10-35 ppt. Optimum: 24.0+ ppt.
  11. Dissolved oxygen: affects respiration and survival of shellfish in both bottom and off-bottom culture, especially during or following intense algal blooms. Optimum: 70+% Saturation Levels.
  12. pH: at levels below 7.5, calcium uptake and retention for shell growth can become impaired. Optimum: 7.80+.
  13. substrate composition: (for bottom culture, avoid soft mud). Range: mud - rock. Optimum: firm gravel/sand/mud.
  14. Intertidal slope: (for bottom culture) limits available culture area at optimal growout position on beach. Range: 5:1 to >15:1. Optimum: >15:1.

Socio-economic or Suitability Factors for Oyster Capability

  1. Growing water classification (approved or not; for bottom and off-bottom culture; more information on classification is provided below).
  2. Biotoxin monitoring availability and PSP closure frequency (more information on biotoxins/PSP is provided below).
  3. User conflicts or zoning issues (local approvals for operation).
  4. Labour availability and cost.
  5. Transportation/accessibility issues (cost and safety of access to site and transport of product to market: access by road or water, distance/time to markets).
  6. Other marketability factors: (e.g. cadmium levels may affect suitability for certain markets, such as Europe [1 ppm wet threshold] and Hong Kong [2 ppm wet threshold]).
  7. Legal issues: oyster farming has regulations and protocols that involve federal, provincial and local governmental jurisdictions.
  8. Upland owners: unless you own the property upland of the potential site, there will be a need to inform the owner(s) and possibly obtain their consent to placement of improvements if these potentially affect riparian access.
  9. Business plan: the best means to integrate the biophysical and suitability factors with realistic economic goals and projections of costs and returns. Review and update regularly.

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Do I need a licence or a tenure/lease to raise oysters commercially? If so, what do I need?

Yes, before an applicant can receive an Aquaculture Licence to farm oysters, one must prepare a Shellfish Management Plan for the species of interest. For marine sites (mostly provincial Crown Land), a shellfish tenure (see below) must also be acquired (by assignment of an existing tenure or application for a new tenure from the Integrated Land Management Bureau [ILMB]). A shellfish lease is a form of shellfish tenure with greater security features. Application packages for Shellfish Management Plans and tenures are available at: http://www.agf.gov.bc.ca/clad/tenure_programs/programs/aquaculture/shellfish/index.html

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Do I have to consult with the public or other interested parties when planning to develop an oyster site?

Yes, if the site is on public or Crown Land/water, under the Land Act of BC and the Navigable Waters Protection Act (Canada), each applicant must consult with adjacent upland owners and First Nations who have traditional territories in the area. The agencies with jurisdiction provincially (ILMB) and federally (Transport Canada) can provide information on consultation requirements.

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What is Paralytic Shellfish Poisoning?

Paralytic Shellfish Poisoning (PSP) refers to the potentially fatal condition resulting from toxic phytoplankton that filterfeeders like oysters ingest during Harmful Algal Blooms (sometimes called “red tides” when they discolour the water). These phytoplankton can produce biotoxins that paralyse humans and other vertebrates, but not the shellfish. To prevent cases of PSP, all shellfish growing areas in BC are regularly monitored for these biotoxins (see CFIA: http://www.inspection.gc.ca/english/anima/fispoi/manman/cssppccsm/append5e.shtml. If levels rise to a threshold level, the growing area affected is closed to harvest of shellfish. PSP and other marine biotoxin closures in BC are posted at the following website: http://www.pac.dfo-mpo.gc.ca/ops/fm/shellfish/biotoxins/closures/pspclosures_e.htm

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Are there other water quality standards for oyster farming and harvesting?

Yes, shellfish growing and harvest areas must undergo a shellfish classification process before shellfish such as oysters can be harvested commercially. Classification is a two part process, involving a water quality survey (to verify there are safe low levels of fecal coliform bacteria) and a shoreline survey (to identify if there are sources of potential contamination in the vicinity), under the scientific authority of Environment Canada and the Canadian Shellfish Sanitation Program (CSSP: see http://www.pyr.ec.gc.ca/EN/Shellfish/index.shtml for description and contact information).

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How/where can I market farmed oysters?

All bivalve shellfish, including oysters, must be delivered to a registered shellfish processing plant before they can be sold to consumers. The processing plant is the first point of inspection for this product which is vulnerable to contamination as described above. (A list of some of the registered processing plants which handle oyster products is available at: http://bcseafoodonline.com/oyster_1.asp ).

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