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Canadian Shellfish Sanitation Program manual
Section B – Shellfish harvest areas

4. Monitoring programs

4.1 Sanitary

To minimize the potential health risks associated with consuming shellfish, it is necessary to survey bacteriological water quality in shellfish harvest areas and to identify actual and potential sources of pollution.

Following such sanitary surveys, the shellfish harvest areas are classified as to their suitability for harvesting shellfish, according to accepted water quality standards and general sanitary conditions in the shellfish harvest area.

The following sections describe the types of surveys used to assess shellfish harvest areas and the principles used in assigning specific classifications to these areas.

ECCC's marine water quality monitoring program is the foundation for the sanitary control of shellfish. The program is designed to identify and evaluate all sources of sanitary pollution to shellfish harvest waters. The classification of shellfish harvest areas, with respect to actual and potential sources of sanitary pollution, is of paramount importance in determining the suitability of shellfish for human consumption.

There is extensive evidence of illness in humans associated with consuming shellfish contaminated by fecal wastes of warm-blooded animals, naturally-occurring bacteria and algal biotoxins. The more common of these illnesses include typhoid, salmonellosis, gastroenteritis, infectious hepatitis, norovirus, Vibrio parahaemolyticus and Vibrio vulnificus infections, paralytic shellfish poisoning, and amnesic shellfish poisoning.

Sanitary pollution of shellfish harvest areas can occur from a variety of sources and under many different conditions. Generally, pollution sources are divided into two broad categories: point and non-point.

  • A point source of pollution enters the receiving water at discrete, measurable locations such as discharges from wastewater treatment and collection systems.
  • Non-point source pollution refers to contamination from sources related to the activities of humans and to natural processes in the watershed, which are diffuse or dispersed, such as agricultural runoff. Such sources do not enter at discrete, identifiable locations and are difficult to measure or define.

Both point and non-point pollution sources can release chemical and/or microbiological contaminants of public health concern.

4.1.2 Water quality surveys of shellfish harvest areas

Surveys of the water quality in shellfish harvest areas are the basis for assigning and maintaining the classification of an area as suitable for shellfish harvest.The type of survey required for a given area depends on prior knowledge of water quality and pollution source types. Surveys are categorized as being one of the following types:

  • comprehensive
  • annual review
  • re-evaluation
4.1.2.1 Comprehensive surveys

The comprehensive survey is a detailed evaluation and assessment of all environmental factors, including actual and potential sanitary pollution sources that affect the water quality in a shellfish harvest area.

A comprehensive survey is conducted in areas where previous data are non-existent or obsolete, or where significant changes have occurred in the pollution status of the area that may affect its classification.

The tasks and considerations when conducting a comprehensive survey are

  • a shoreline sanitary investigation designed to identify and evaluate all actual and (potential) sources of sanitary pollution affecting the shellfish harvest area
  • an evaluation of the meteorological and hydrographic factors that may affect the distribution of sanitary pollutants throughout the area
  • a bacteriological examination of the harvest waters that is designed to determine the extent of fecal contamination, and provide quantitative data for the classification of harvest waters (where available, other bacteriological data/studies should also be considered for classification purposes)
  • sampling of the harvest waters
    • A minimum of 15 samples must be collected at each sample site before classification.
    • In remote shellfish harvest areas and those not impacted by point sources of pollution, the number of samples collected may be modified.

Bacteriological monitoring should be conducted under varied environmental conditions. The number and location of sample sites selected should be adequate to produce the data necessary to effectively evaluate all point and non-point sources of sanitary pollution. In certain circumstances, alternative sampling strategies may be used. Sampling considerations such as site selection, sampling frequency and data analysis may vary, and are addressed through operational guidance implemented by ECCC.

4.1.2.2 Annual review survey

Annual review surveys reassess and confirm the classification of the shellfish harvest area. They are done to confirm that sanitary conditions have not changed and that the classification is still valid.

The tasks done during annual review surveys include:

  • a file review to evaluate the changes in existing and new sanitary pollution sources
  • a shoreline sanitary investigation, if deemed necessary
  • a minimum of five water quality samples for fecal coliform per year collected at each marine sample site for non-remote areas and two samples per year for remote areas
4.1.2.3 Re-evaluation survey

A re-evaluation survey updates the classification of an area, requiring an in depth assessment of the elements of the comprehensive survey. The complexity and extent of a re-evaluation survey will be specific for each shellfish harvest area.

The tasks done during a re-evaluation survey include:

  • a complete re-evaluation of the classification of each shellfish harvest area once every three years, including, at minimum, the last 15 water samples from each representative marine sample site (this requirement may be modified in remote shellfish harvest areas if warranted by the sanitary conditions in the area)
  • a re-evaluation of a shellfish harvest area within one year, if the annual review shows that the sanitary quality of an area is likely to be significantly altered by changes in the pollution sources
4.1.2.4 Documentation
  • ECCC will prepare reports for each comprehensive and re-evaluation surveys, and annual reviews. These written reports contain data and assessments for components of the surveys described in the previous sections.
  • ECCC will maintain a file that contains all pertinent sanitary survey information, including the dates and results of proceeding surveys and reports, for each classified shellfish harvest area.

4.1.3 Classification of shellfish harvest areas

A classified area is a shellfish harvest area where a comprehensive survey has been completed and the appropriate classification designation has been adopted by a Regional Interdepartmental Shellfish Committee (RISC). Classified areas are routinely monitored according to CSSP requirements for fecal coliform contamination and marine biotoxin content. This provides reasonable assurance that the public is protected from shellfish-related illnesses.

The CSSP recognizes five classification categories

  • approved
  • conditionally approved
  • restricted
  • conditionally restricted
  • prohibited

Specific area classifications and their boundaries are assigned to shellfish harvest areas based on sanitary and water quality survey results. ECCC classification recommendations are presented to the RISCs for discussion and final approval.

The CSSP may also recognize sub-tidal and offshore areas as acceptable for harvesting in addition to the five classification categories listed above. Water quality monitoring may not be required due to the very low risk of contamination in such areas, which may be deemed acceptable based on meeting the criteria in section 4.1.3.6.

4.1.3.1 Approved classification

A shellfish harvest area may be classified as approved if the area is not contaminated with pathogenic micro-organisms to the extent that consuming the shellfish might be hazardous. A harvest area may be classified as approved if the national shellfish growing area water quality standard is met. The following criteria must be met at representative marine sample sites:

  • the median fecal coliform most probable number (MPN) does not exceed 14/100 mL, and not more than 10% of the samples may exceed a fecal coliform MPN of 43/100 mL, for a five-tube decimal dilution test; or
  • the geometric mean fecal coliform MPN does not exceed 14/100 mL, and the estimated 90th percentile of fecal coliform MPNs does not exceed 43/100 mL, for a five-tube decimal dilution test and actual and potential sources of pollution sources have been identified, and these have been determined not to impact the shellfish harvest area and
  • the shellfish harvest area is not otherwise contaminated by harmful substances
4.1.3.2 Conditionally approved classification

A shellfish harvest area may be classified as conditionally approved if it meets the approved classification criteria for a defined period, as determined by the shellfish control authority. Such shellfish harvest areas may be subject to intermittent pollution such as releases/discharges from wastewater and collection systems, seasonal human or wildlife populations, non-point source pollution or seasonal boating activity.

Requirements for a conditionally approved area

  • sources of pollution are predictable and can be easily identified and quantified
  • a conditional management plan is in effect that specifies the criteria under which the area is placed in open or closed status
  • all additional requirements described in the conditional management plan are fully met

A conditionally approved shellfish harvest area that does not meet the approved shellfish harvest area criteria is placed in closed status by the shellfish control authority. To return the area to open status, verification activities may be required as described in the relevant conditional management plan.

4.1.3.3 Restricted classification

A shellfish harvest area may be classified as restricted if water quality exceeds the standard for the Approved classification to the extent that consumption of the shellfish might be hazardous. Evidence of potential pollution sources is also sufficient to place the harvest waters in the restricted classification.

An area may be classified as restricted if it exceeds the approved classification standard but is not contaminated to the extent where it would be classified as prohibited.

The harvest of shellfish is not permitted from such areas, except by licence issued by DFO under the Management of Contaminated Fisheries Regulations.

If a restricted area is to be harvested for the purpose of depuration, the median or geometric mean fecal coliform MPN of water must not exceed 88/100 mL and not more than 10% of the samples can exceed a fecal coliform MPN of 260/100 mL, for a five-tube decimal dilution test.

Shellfish may be relayed from a restricted area at the discretion of the shellfish control authority. There is no specific water quality standard when shellfish are relayed from a restricted area..

Depending on the degree of contamination in the harvest waters, it may not be possible to adequately depurate or naturally purify the shellfish. Such areas are classified as prohibited and harvest is not permitted (see section 4.1.3.5).The restricted classification will not be changed without at least a re-evaluation survey report indicating improvements in sanitary conditions and water quality that meet the appropriate classification standards.

4.1.3.4 Conditionally restricted classification

A shellfish harvest area may be classified as conditionally restricted if it meets the restricted classification criteria for a defined period, as determined by the shellfish control authority. Such shellfish harvest areas may be subject to intermittent pollution such as releases/discharges from wastewater and collection systems, seasonal human or wildlife populations, non-point source pollution or seasonal boating activity.

Requirements for a conditionally restricted area:

  • pollution source is predictable and can be easily identified and quantified
  • a conditional management plan is in effect that specifies the criteria under which the area is placed in open or closed status
  • all additional requirements described in the conditional management plan are fully met

A conditionally restricted shellfish harvest area which does not meet the restricted shellfish harvest area criteria will be placed in closed status by the shellfish control authority. To return the area to open status, verification activities may be required as described in the relevant conditional management plan.

4.1.3.5 Prohibited classification

Shellfish must not be harvested from prohibited areas for any purpose, with the exception of harvesting for seed, spat, bait and for scientific purposes, all of which must be fished under the Management of Contaminated Fisheries Regulations (see section 8.2 Licensing of harvesters).

The following areas will be defined as prohibited areas:

  • the area within a minimum 300 metre radius around points of continuous or intermittent discharge from a sanitary sewage system
  • the area around points of continuous sanitary discharge which does not achieve adequate reduction of viral particles through a combination of wastewater treatment and dilution in the shellfish harvest area
  • the area within a minimum 300 metre radius around industrial outfalls
  • the area within a minimum 125 metre radius around marinas, wharves, finfish net pens, float homes or other floating living accommodation facilities
  • the area within a minimum 25 metre radius from a float home or floating living accommodation facility located within a shellfish tenure/lease where a zero effluent discharge management plan is in effect
  • areas where, due to the degree of contamination in the harvest waters (such as waters having excessive concentrations of fecal material or other poisonous or deleterious substances), it may not be possible to adequately depurate or naturally purify the shellfish
4.1.3.6 Subtidal/offshore areas

Sub-tidal shellfish harvest areas within five kilometres of land, which are also well-removed from pollution sources, are at low risk of becoming contaminated with fecal coliform bacteria. The sanitary quality of such areas used for direct shellfish harvesting may be more appropriately assessed by evaluating actual and potential pollution sources in the area. Water quality sampling is not required in these areas.

The RISC will consider proposals submitted to harvest shellfish from sub-tidal areas. If the committee is satisfied that the information submitted by the CFIA, ECCC and DFO confirms these waters are safe, it may deem the sub-tidal waters to be acceptable for harvest for direct consumption.

Offshore areas beyond five kilometres from land are considered acceptable for harvesting unless otherwise closed.

4.1.3.7 Process for classification/declassification recommendations: Role of the Regional Interdepartmental Shellfish Committee

ECCC will present survey results and recommendations for classification changes based on sanitary and water quality surveys to the appropriate RISC as soon as practical after the surveys are completed. The committee will consider the information along with other relevant knowledge such as biotoxin levels and/or other potential contaminants and will classify/declassify the area accordingly.

4.1.3.8 Declassification of a shellfish harvest area

Declassification is the process to remove a designated classification from a shellfish harvest area, which results in the area becoming unclassified and therefore no longer subject to CSSP controls.

Declassification may be adopted by RISCs where levels of harvest activity no longer justify routine sanitary and/or biotoxin monitoring. Unclassified areas are not monitored according to CSSP requirements and shellfish should not be harvested from these areas.

4.1.3.9 Documenting classification changes

All ECCC classification recommendations will be documented in the survey reports. All declassification recommendations will be documented accordingly. Discussion and decisions of the RISC will be reflected in the records of the regional meetings and may also be reflected in ECCC reports.

4.2 Marine biotoxins

Marine biotoxins are produced by certain species of naturally occurring microscopic algae that bloom under favourable hydrographic conditions. Filter-feeding bivalve shellfish accumulate the biotoxins when they ingest toxic algae as a food source. Consuming shellfish containing elevated concentrations of biotoxins can lead to illness and even death. Biotoxins do not kill the shellfish nor do they cause any noticeable changes in the appearance, smell or taste of shellfish that would alert consumers that the shellfish contain unacceptable levels of biotoxins. The algae bloom will dissipate as water temperature, salinity, and nutrient levels become less favourable. The shellfish will eventually cleanse themselves of the biotoxin and be safe for human consumption.

Any filter feeding bivalve can accumulate biotoxins. In Canada, many species of clams, oysters, mussels and scallops have been affected. The rates at which biotoxins are accumulated and eliminated vary with species. Animals that feed on bivalves may also develop elevated levels of biotoxins in their tissues. Biotoxins have been detected in lobsters, crabs and whelks, as well as other predatory gastropods.

In Canada, the following marine biotoxins have been found:

  • saxitoxins, which are associated with paralytic shellfish poisoning (PSP)
  • domoic acid, which is associated with amnesic shellfish poisoning (ASP)
  • okadaic acid, dinophysis toxins and pectenotoxins which are associated with diarrhetic shellfish poisoning (DSP)

The illnesses associated with exposure to elevated levels of biotoxins are named for the most notable symptom they cause, namely paralysis, amnesia and diarrhea. In Canada, serious illnesses as well as occasional deaths have occurred due to the consumption of bivalve shellfish contaminated with high levels of paralytic shellfish poisoning and amnesic shellfish poisoning. Illnesses but no deaths have been attributed to diarrhetic shellfish poisoning.

In order to protect consumers, the government has established programs to monitor biotoxin levels in classified areas and to prevent the harvesting of shellfish containing elevated biotoxin levels. The CFIA is responsible for collecting and analysing shellfish samples, as well as making recommendations to DFO to open and close shellfish harvest areas. Monitoring for marine biotoxins in offshore areas is the responsibility of the harvester or the licensed operator.

4.2.1 Management of marine biotoxins

4.2.1.1 Harvest area monitoring

Monitoring programs established by the CFIA are the primary means used to manage marine biotoxins in Canada. Shellfish samples are collected from predetermined areas and at specified frequencies based on factors such as season, historical biotoxin levels, and harvesting activity. If increasing biotoxin levels are observed, sampling frequency may increase in accordance with the rise of the level of biotoxins to ensure that any required closures are implemented in a timely fashion. In cases where additional samples cannot be obtained, the CFIA may recommend a closure of a shellfish harvesting area based on previous knowledge of the risk posed by biotoxins in a particular area. The CFIA may also recommend a closure of a shellfish harvesting area when biotoxin levels are increasing rapidly but have not exceeded standards.

The objective of the monitoring programs is to ensure shellfish harvest areas are placed in closed status when unacceptable biotoxin levels are reached. The Canadian maximum levels (standards) for biotoxins in bivalve shellfish edible tissue are established by Health Canada. The CFIA will recommend to DFO to place a shellfish harvest area in closed status when:

  • paralytic shellfish poisoning (saxitoxin equivalents) are ≥80 ug/100g
  • amnesic shellfish poisoning (domoic acid)levels are ≥20 ug/g;
  • diarrhetic shellfish poisoning (okadaic acid and/or DTX, singly or in combination) levels are ≥0.20 ug/g
  • pectenotoxins levels are ≥0.20 ug/g

An area may be returned to open status when three consecutive acceptable samples taken over a 14 day period are acceptable and show a downward trend in toxicity. Consideration of adjacent area results are taken in to account when decisions are made to return a shellfish harvest area to open status.

Areas that are closed based on the predicted rapid rise in biotoxin levels may be opened earlier than the standard 14-day closure if a subsequent sample or samples indicate that the biotoxin levels never reached unacceptable levels and the biotoxin levels are decreasing.

4.2.1.2 Biotoxins in scallops and predatory gastropods

Scallops accumulate biotoxins in their tissues similar to other bivalves; however, certain parts of some species of scallops do not accumulate biotoxins. For example, the adductor muscle, commonly referred to as meat, of Atlantic sea scallops (Placopecten magellanicus) does not accumulate biotoxins. Conversely, certain Pacific species such as the purple-hinge rock scallop (Crassedoma giganteum) and the Pacific scallop (Patinopecten caurinus x) are known to accumulate paralytic shellfish poisoning toxins in the adductor muscle.

Predatory gastropods such as whelks may be exposed to biotoxins when they ingest contaminated bivalves. Like scallops, the tissues of some whelks may contain concentrations of biotoxins.

4.2.1.3 Monitoring at establishments

Licensed operators of processing establishments must be aware of the biotoxin risk associated with the processing of various species and must take appropriate preventive control measures to eliminate or reduce the food safety risk as required. Preventive control measures may include:

  • harvesting from areas in open status,
  • monitoring biotoxin levels of incoming shellfish and gastropods, or
  • removing certain tissues that are known to contain the highest concentrations of biotoxins.

The CFIA may take samples for biotoxin analysis from shellfish processing establishments in order to verify that licensed operators of shellfish establishments have effective preventive controls and that shellfish are in compliance with Canadian standards.

If a verification sample indicates that biotoxin levels in shellfish do not meet a standard, and the licensed operator's preventive controls are deemed acceptable, the CFIA may recommend to DFO to close the implicated harvest area. Follow-up actions also include sampling at the harvest area to confirm biotoxin levels, and investigating whether associated production lots include shellfish that exceed the Canadian standards.

4.2.1.4 Illness due to marine biotoxins

A shellfish harvest area may be placed in closed status as an interim measure when a marine biotoxin related shellfish illness is suspected or confirmed. The area and size of closure will depend on the results of an investigation. The affected area will remain closed until an investigation is complete and the area is deemed safe to harvest.

5. Status

5.1 Open and closed status

The status of a shellfish area is distinct from its classification and may be open or closed for the harvesting of shellfish.

  • Areas classified as approved, conditionally approved and in open status or offshore areas that are not otherwise in closed status are deemed acceptable to harvest for direct to market sales.
  • Areas classified as restricted or conditionally restricted and in open status are eligible for harvesting and subsequent decontamination through relay, depuration or other equivalent methods provided the harvester is licensed under the Management of Contaminated Fisheries Regulations.

Generally, areas in closed status are not eligible for harvesting except under the conditions described in Monitoring programs – Sanitary. Any shellfish harvest area may be temporarily placed in the closed status in the event that degradation in shellfish harvest area water quality could be caused by events such as excessive rainfalls, flooding caused by severe storms, or hydrocarbon spills. The management of such unpredictable events is addressed in section 6. Responsive programs.

Shellfish harvest areas that are in open status can be placed in closed status for several reasons. The most common reasons are:

  • the biotoxin levels in shellfish do not meet the standard, or indicate an upward trend
  • the conditions for harvesting safe shellfish in a conditionally managed area are not met, such as
    • a wastewater treatment plant or collection system fails or is bypassed
    • a rainfall threshold is exceeded
    • the water quality has deteriorated with a change in season
  • an emergency event has occurred such as
    • a significant rainfall
    • a fuel/oil or chemical spill
  • the microbiological levels in shellfish exceed CSSP guidelines

5.2 Communication of status with stakeholders

The CFIA, DFO, and ECCC have various communications mechanisms in place to ensure that industry stakeholders and the public are aware of events that may affect the status of shellfish harvest areas. Types of communication measures may include:

  • updating the status of shellfish harvest areas on the national CSSP shellfish mapping application located on the DFO website.
  • broadcasting notices over a commercial or marine radio station, a radio station operated by DFO, or a radio station located on a vessel under contract to DFO
  • publishing notices in a newspaper that is circulated in the vicinity of the area affected by the notice
  • posting the notice in the area or in the vicinity of the area affected by the variation
  • transmitting the notice by electronic means to stakeholders
  • posting the notice on the DFO's website or the province's website
  • having a fishery officer or fishery guardian give oral notice thereof to those persons;
  • publishing the notice in the next issue of a sport fishing publication, published periodically by the applicable province or by DFO
  • emailing or faxing biotoxin level reports

6. Responsive programs

6.1 Conditional management of shellfish harvest areas

ECCC may recommend that an area be classified as conditionally approved and/or conditionally restricted based on either the performance of a wastewater treatment and/or collection system, rainfall or season.

If the RISC adopts the recommendation that the area be classified as conditionally approved or conditionally restricted, the area will remain in the closed status until an appropriate conditional management plan is developed.

The objective of a conditional management plan is to provide a framework for improved management of shellfish harvest areas that are adjacent to waste water treatment plants, are affected by rainfall, or are affected by seasonal changes. Where the conditionally approved or conditionally restricted area is classified based on the operation of a wastewater treatment and/or collection system, DFO will facilitate developing a conditional management plan with CFIA, ECCC, the local municipality and other stakeholders. Where an interest is expressed to operate a conditional area based on season or rainfall, DFO will facilitate developing the conditional management plan in collaboration with the CFIA, ECCC and other stakeholders.

6.1.1 Specific criteria for conditionally approved areas

Conditionally approved areas must be immediately placed in closed status when the criteria established in the conditional management plan are not met.

A conditionally approved area in closed status will not be re-opened to shellfish harvesting until all of the following are achieved.

  • The criteria established in the conditional management plan are fully met.
  • A time has elapsed that is sufficient, under environmental conditions, to permit natural biological cleansing of the shellfish.

Conditionally approved areas based on the performance of wastewater treatment and collection systems may be re-opened 7 days after the release/discharge event ceased and verification indicates that the bacteriological quality of the water and shellfish meets approved area standards.

  • For water quality, the median fecal coliform levels of the samples collected for the area in one survey cannot exceed 14 MPN/100 mL and no more than 10% of the samples can exceed 43 MPN/100 mL.
  • In five (5) shellfish samples, only 1 fecal coliform result may exceed 230 MPN/100 g, and no result may exceed 330 MPN/100 g.

Conditionally approved areas based on performance of wastewater treatment and collection systems may return to open status without verification sampling if a minimum of 21 days has elapsed since the release/discharge event ceased.

6.1.2 Specific criteria for conditionally restricted areas

Conditionally restricted areas are immediately placed in closed status when the criteria established in the conditional management plan are not met. A conditionally restricted area which has placed in closed status will not re-open to shellfish harvesting until:

  • the criteria established in the conditional management plan are fully met;
  • a time has elapsed which is sufficient, under environmental conditions, to permit shellfish to return to background levels of microbiological contaminants

Conditionally Restricted areas based on the performance of wastewater treatment and collection systems may be re-opened 7 days after the release/ discharge event ceased and verification indicates that the bacteriological quality of the water and shellfish meets appropriate standards.

  • for depuration or relay less than 14 days, the fecal coliform median of the water samples collected for the area in one survey cannot exceed 88 MPN/100 mL and no more than 10% of the samples can exceed 260 MPN/100 mL. Shellfish samples shall not exceed 2300 MPN/100 g.
  • for 14 day or longer relay, no samples are required

Conditionally Restricted areas based on the performance of wastewater treatment and collection systems may return to open status without verification sampling if a minimum of 21 days has elapsed since the release/discharge event ceased.

6.2 Emergency events

An emergency situation may include, but is not limited to

  • significant weather events
  • flooding
  • sanitary wastewater discharges
  • oil or toxic chemicals

Emergency closures do not include those resulting from elevated biotoxin levels, nor conditionally managed areas based on the operation of wastewater treatment and collection systems.

The CSSP control authorities will place a shellfish harvest area in closed status as soon as possible upon notification of an emergency event. The size of the closure will be based either on predetermined closure boundaries, if they are available, or by an assessment of the available emergency event information. If additional emergency event information becomes available, the size of the closure may be modified.

Shellfish harvest areas affected by an emergency event will remain in closed status for at least 7 days. ECCC and CFIA will collaborate to evaluate the situation and advise if changes in the closure status are warranted. This may be achieved through sampling of water and shellfish to test for factors relevant to the conditions in the area that led to the closure. Shellfish and water samples are collected from sites that are representative of the shellfish harvest area. The number of shellfish and water sites to be sampled will be determined by CFIA and/or ECCC on a case-by-case basis. This is dependent on the size of the closure area and the location of shellfish resource. In order to re-open an area, the shellfish must meet the following criteria:

  • ≤230 fecal coliform/100 g in approved areas,
  • ≤2300 fecal coliform/100 g in restricted/conditionally restricted areas that are harvested for depuration, and
  • not contaminated with poisonous or deleterious substances.

In addition, the water quality must meet the criteria stipulated in section 4.1.3.

If the emergency closure is in response to a discharge of sewage or significant rainfall, the affected area may be re-opened upon recommendation either:

  • after a minimum of 7 days, based on acceptable water and shellfish sample results, or
  • after a minimum of 21 days, without sampling

6.3 Shellfish harvest area investigation – Unacceptable microbiological results in shellfish

The CFIA routinely inspects the preventive control plans of licensed operators. Part of the inspection process may include sampling shellfish for compliance to Canadian Standards and Guidelines for Microbiological Safety of Foods. A harvest area investigation will be initiated by the CFIA if a shellfish sample fails to meet the microbiological standard for E. coli or Salmonella and, it has been determined that the licensed operator has implemented appropriate preventive controls.

The CFIA or authorized samplers will sample (5 representative units) of shellfish from the implicated shellfish harvest area and test for E. coli and/or Salmonella. The shellfish sample sites will be determined on a case-by-case basis and will be depending on the location of shellfish resources. If the results are unacceptable, the area will be placed in closed status for a minimum of 7 days. The size of the closure will be reflective of the sampling sites and results.

The CFIA will consult with ECCC as to possible contamination sources, and will consider the information in establishing when and where sampling to re-open the shellfish harvest area should occur.

  • If shellfish sampling results are acceptable, the CFIA, pending concurrence from ECCC, will recommend to DFO to return the shellfish harvest area to open status.
  • If the shellfish results are unacceptable, the shellfish harvest area will remain in closed status until ECCC reassesses the area.

6.4 Response to shellfish related illnesses and outbreaks

6.4.1 Investigation responsibilities

Public health authorities are responsible for the investigation and response to illnesses and outbreaks. Provincial and local public health authorities lead the response to enteric illnesses and outbreaks within their respective jurisdictions. The Public Health Agency of Canada leads the response to enteric illness outbreaks that span more than one Canadian province or territory or involve Canada as well as another country, pursuant to the Food-borne Illness Outbreak Response Protocol. When shellfish are implicated in an illness or an outbreak, the Canadian Shellfish Sanitation Program partners participate in the response as appropriate.

6.4.2 Epidemiological information and food safety investigations

Provincial public health authorities and the Public Health Agency of Canada provide the CFIA with information respecting potential epidemiological associations between reported illnesses and shellfish consumption. The CFIA will use the epidemiological illness data in conjunction with evidence gathered as part of a CFIA-led CSSP food safety investigation to assess the link between shellfish from a specific shellfish harvest area, landfile or lease and reported illnesses. The CFIA's food safety investigation will assess whether the illness is related to a shellfish harvest area (whole or part of), landfile or lease or is the result of processor post-harvest contamination.

6.4.3 Shellfish harvest area closures – Norovirus contamination

The CFIA will recommend to DFO to place an implicated shellfish harvest area (whole or part of), landfile or lease in closed status if:

  • shellfish from a specific area are the suspected vector of infection and there are/is:
    • two single source illness clusters in a 21 day harvest period or,
    • one single source illness cluster and 2 multi-source illness clusters in a 21 day harvest period or,
    • a single source illness cluster comprised of a large number of illnesses resulting from a specific harvest for a public or private event.

or,

ECCC will recommend to DFO to place an implicated shellfish harvest area (whole or part of), landfile or lease in closed status if there has been a confirmed sanitary release as per section 6.2 - Emergency Events.

Follow-up representative shellfish sampling at the shellfish harvest area, landfile or lease will be conducted to determine the level and extent of contamination. A shellfish area (whole or part of), landfile or lease may return to open status if investigative sample results are acceptable by CFIA and is supported by the current CFIA food safety investigation.

The shellfish harvest area (whole or part of), landfile or lease will remain in closed status when investigative samples from approved areas exceed any of the following criteria:

  • E. coli (n=5, c=1, m=230 MPN/100 g, M= 330 MPN/100 g) or
  • Norovirus (n=5 detected in any sample)

If sample results are unacceptable for norovirus, the closure will be in effect for a minimum of 30 days. If sample results are unacceptable for E. coli only, the closure will remain in place for a minimum of 7 days.

6.4.4 Shellfish harvest area re-opening – Norovirus contamination

  1. For closures due to Norovirus

    CFIA with ECCC's concurrence will recommend to DFO that a shellfish harvest area, landfile or lease be returned to open status when:

    • ECCC has confirmed that there is no evidence of new or ongoing sanitary concerns and,
    • after 30 days, CFIA shellfish testing results meet the following criteria:
    • E. coli (n=5, c=1, m=230 MPN/100 g, M= 330 MPN/100 g)
    • Norovirus (n=5 not detected), and
    • the recommendation is supported by the current CFIA food safety investigation.

    or,

    • after 60 days, without testing, when representative measurement of the harvest area water temperature indicates it has remained at 10 degrees Celsius or higher for the entire time period, and
    • the recommendation is supported by the current CFIA food safety investigation.
  2. For closures due to E. coli only

    CFIA with ECCC's concurrence will recommend to DFO that a shellfish harvest area, landfile or lease is returned to open status when:

    • ECCC has confirmed that there is no evidence of new or ongoing sanitary concerns and,
    • after 7 days, CFIA shellfish testing results are in compliance to the following criterion:
      • E. coli (n=5, c=1, m=230 MPN/100 g, M= 330 MPN/100 g), and
      • the recommendation is supported by the current CFIA food safety investigation.

6.4.5 Risk assessment

The CFIA will consult with Health Canada to determine the level of risk that any shellfish in distribution might pose and take follow-up action as required as per CFIA's food incident response process.

7. Support programs

7.1 Laboratories

This section provides CSSP laboratories with information on:

  • analytical methods and quality assurance requirements associated with examining seawater and shellfish
  • references and information necessary for conducting bacteriological, marine biotoxin, chemical and physical tests

It is important for laboratories to adhere to the policy referenced below. This will provide the uniformity necessary to produce consistent reliable laboratory results upon which public health decisions can be made in determining whether shellfish are suitable for human consumption.

Quality assurance

All laboratories performing CSSP testing for regulatory purposes must use approved reference methods and be accredited to the international standard ISO/IEC 17025 "General Requirements for the Competence of Testing and Calibration Laboratories" by a recognized Canadian accrediting body. The laboratory's scope of accreditation must include methods specified by the CSSP.

A joint CFIA-ECCC CSSP Laboratory Committee will serve as a key contact point for internal, external and international discussion and inquiries related to laboratories when necessary.

The following methodologies are considered appropriate to support CSSP activities.

Reference methods – Microbiological

Reference methods – Marine biotoxins

Laboratories shall use either:

  • official methods for which the laboratory has demonstrated that they are able to achieve the published method performance parameters or
  • other methods that have been validated and meet Codex Alimentarius performance criteria for marine toxins

Reference methods – Chemical and physical

  • official methods for which the laboratory has demonstrated that they are able to achieve the published method performance parameters or
  • other methods that have been validated and meet Codex Alimentarius method performance criteria
  • results of all chemical and physical analysis must be expressed in standard units

7.2 Non-government of Canada samplers

ECCC and the CFIA conduct testing of shellfish harvest area marine waters and shellfish, respectively, for compliance with Canadian standards. The CSSP Manual describes what samples are collected by the shellfish control authorities and what criteria are applied in order to be acceptable to CSSP requirements and quality assurance programs.

In some circumstances it is preferable that sampling be conducted by non-Government of Canada (GoC) samplers. In these instances a sampling arrangement/agreement, such as an MOU, may be established between ECCC or the CFIA and a non-GoC party to support delivery of the CSSP.

Non-GoC parties are advised that other policies are taken into account when a decision is made on the establishment of a non-GoC sampling arrangement. The CSSP partners reserve the right to limit the number of non-GoC sampling arrangements on a regional or national basis.

7.2.1 Objective

The goal of this policy is to establish minimum criteria to enable the CSSP partners to enter into non-GoC sampling arrangements. Samples taken under such arrangements are deemed appropriate to be used by the shellfish control authority to make a regulatory decision on the status of a shellfish harvest area.

7.2.2 Scope

This policy applies to all marine water and shellfish sampling conducted by non-GoC samplers for submission to a CSSP laboratory.

This policy may be applied to:

  • routine sampling for water quality or biotoxin monitoring programs;
  • sampling to support revoking closures in conditional areas;
  • sampling to support revoking emergency closures or in areas closed due to unacceptable microbiological results in shellfish; or
  • special sampling projects such as scientific research, wastewater treatment plant studies, sampling related to remediation work, new classification, or classification changes

This policy does not apply to contracts issued for CSSP sampling under Public Works Government Services Canada rules and departmental/agency rules. However, similar criteria may be incorporated into any contracts issued.

7.2.3 Requirements

When sampling is conducted for the CSSP, a formal arrangement must be completed between the applicable department and the sampler. The arrangement is to stipulate as applicable requirements such as:

  • contributions to be made by each party
  • duties to be conducted by each party
  • terms and conditions
  • arrangements for initial and ongoing training
  • signatures from each party representative
  • a work plan and sampling schedule
  • sampling procedures (or a reference to existing ones)
  • a reference to applicable provincial or federal Occupational Health and Safety (OHS) requirements and where applicable
  • Transport Canada vessel requirements

The arrangement will include an audit and training component to verify that the samples are collected as per the sampling procedures found within.

Individual samplers will be deemed CSSP recognized (i.e. added to list of approved CSSP samplers) if they have completed a signed agreement, completed all prescribed training, and possess all applicable certifications and licences. The list of prescribed training, certifications, and licences will be provided by ECCC and/or the CFIA to the interested parties.

The responsibility for recognizing non-Government of Canada samplers, including arrangement development, training, and evaluation, lies with the individual department or agency. Any arrangement is to be consistent with existing policies such as the CFIA alternative service delivery policy or ECCC policies dealing with third parties.

8. Control of harvesting

8.1 Legal authority

DFO has the legal authority for the enforcement of the shellfish industry, including enacting the opening and closing of shellfish harvest areas under the authority of the Fisheries Act and its supporting Regulations:

The majority of these regulations allow for lawful harvesting of shellfish in approved growing areas. However, due to changing environmental conditions, harvest areas are not always open or approved for all types of shellfish harvest. The Management of Contaminated Fisheries Regulations authorize the minister to close areas to harvests of bivalve molluscs and to take other management measures into consideration when biotoxins, bacteria, chemical compounds or other substances are present in fish habitat to a degree that may constitute a danger to public health. These regulations also allow the Minister to issue special licences with specific provisions to individuals interested in harvesting from restricted and conditionally restricted areas.

8.2 Licensing of harvesters

Shellfish licences

All shellfish harvesters are subject to the same harvest area classification and closure status provisions, regardless of the type of licence they possess. The different types of shellfish harvest licences are outlined below.

8.2.1 Recreational

Before harvesting shellfish from an approved growing area in open status, recreational harvesters are encouraged to consult the DFO website or their local Conservation and Protection detachment to confirm if a shellfish licence is required. Some regions have different requirements for recreational shellfish harvesting and the onus is on the harvester to comply with all laws and regulations regarding the targeted species, the number of shellfish collected and the type of harvest tools used.

8.2.2 Commercial

In order to harvest shellfish in commercial quantities, it is necessary to obtain a commercial licence and comply with the conditions in section 8.1 of the Fisheries Regulations. Each region is subject to different enabling regulations. The onus is on the commercial harvester to comply with all laws and regulations regarding the targeted species, the total allowable catch and the type of harvest tools used.

8.2.3 Aquaculture

In British Columbia only, the Minister of DFO may issue licences to aquaculture operators to engage in aquaculture and prescribed activities. In all other provinces, with the exception of a co-management leasing regime in Prince Edward Island, aquaculture licences are issued by provincial authorities.

8.2.4 Aboriginal

Under the Aboriginal Communal Fishing Licences Regulations (ACFLR), the Minister of DFO may issue a communal licence to an aboriginal organization for shellfish harvesting activities. A communal licence may specify conditions for the proper management and control of the fishery.

8.2.5 Collection of shellfish seed or spat for aquaculture purposes

Shellfish seed and spat may be collected for grow-out from contaminated areas, including prohibited areas, by a licence issued under the Management of Contaminated Fisheries Regulations (DFO, 1990) providing that they are moved to approved growing areas for an acceptable period of time prior to their final harvest and sale for human consumption. The intent is that shellfish referred to as spat or seed is well under the minimum normal marketable size for that species and would require a grow-out period of at least 6 months to reach the market size. Considering that the accumulation and elimination of microbiological and chemical contaminants in shellfish differs, the following requirements shall apply:

  • The grow-out period for spat or seed collected within a microbiologically contaminated prohibited area by a licence issued under the Management of Contaminated Fisheries Regulations (DFO, 1990) must be a minimum of six months.
  • The grow-out period for spat or seed collected within a chemically contaminated prohibited area by a licence issued under the Management of Contaminated Fisheries Regulations (DFO, 1990) must be a minimum of twelve months unless a chemical contaminant reduction study demonstrates elimination in a shorter time period.

8.2.6 Closed or contaminated areas

Section 4(2) of the Management of Contaminated Fisheries Regulations allows for a licence to fish for food purposes in an area that is contaminated, following approval of a decontamination plan.

Decontamination Plans

Commercial fishers and aquaculturists who want to harvest shellfish in a restricted, conditionally restricted, or prohibited area must have a Management of Contaminated Fisheries Regulations licence and a decontamination plan. The proponent must submit a harvesting plan and a decontamination plan with their licence application. DFO will refer the application as applicable to:

  • ECCC to verify the harvesting areas meet CSSP criteria when the shellfish are being harvested for depuration
  • CFIA to verify the decontamination plan meets CSSP requirements, or in cases when relay and depuration are not used, to other requirements under the SFCR

If all program requirements are satisfied, a harvest licence pursuant to the Management of Contaminated Fisheries Regulations will be issued by DFO.

Harvesting shellfish for bait from a prohibited area requires a license under the Management of Contaminated Fisheries Regulations (DFO, 1990).

Harvesting shellfish for scientific purposes from a prohibited area requires a license issued under Section 52 of the Fishery (General) Regulations (DFO 1993) and a license under the Management of Contaminated Fisheries Regulations (DFO, 1990).

8.3 Shellfish closures

The Government of Canada must be able to react quickly to changing circumstances to ensure that the current status of each shellfish growing area is accurately communicated to the public. It is imperative that harvesters are aware if an area is in the open or closed status or if an emergency situation has occurred. An emergency situation includes unusual weather, flooding, elevated biotoxin levels and spills of oil, toxic chemicals or sewage. It could also include a change in status of a conditionally managed area based on the operation of wastewater treatment and collection systems.

In shellfish harvest areas classified as restricted or prohibited, or in any area in closed status, it is necessary to quickly and clearly identify the affected areas and relay accurate information to the public and licensed growers within the aquaculture industry. This notification may vary among regions but generally includes the following:

  • The boundaries of the affected areas marked by CSSP signage, fixed objects or landmarks or otherwise described in a manner which permits easy recognition of the boundaries; and,
  • Information about status of shellfish harvest areas conveyed to harvesters through a number of methods, including:
    • Real-time maps of openings and closures of shellfish harvest areas at the online CSSP mapping application,
    • local media,
    • the DFO webpage,
    • electronic fishery notices,
    • 24 hour recorded information lines
    • notices in affected areas and at shellfish processing plants,
    • Canadian Coast Guard radio, if applicable.

8.4 Patrol

The control of harvesting from shellfish harvest areas is a vital part of the control procedures for a comprehensive shellfish sanitation program. There must be assurances that shellfish are only harvested from approved or conditionally approved areas in open status, or restricted or conditionally restricted areas in open status, with the appropriate licences. Potentially hazardous shellfish must be prevented from reaching the consumer. It is the responsibility of the Conservation and Protection Directorate in each DFO Region to provide sufficient personnel and equipment for surveillance activities that will act as a deterrent to illegal harvesting.

While considerable effort is dedicated to promoting voluntary compliance with the program, persons caught harvesting in a closed area can face a range of enforcement actions such as

  • warnings,
  • loss of catch, equipment,
  • fines,
  • licence suspension/revocation, and/or
  • prosecution

Specific patrol requirements that may be applied to technical and administrative situations vary among Regions. Consequently, each Region develops a patrol policy document and reviews it on a regular basis to keep it current. These policy documents describe patrol organization and activities necessary to deter illegal harvesting. The technical requirements for these policies are outlined in appendix 14.2: Patrol Policy Technical Guidelines.

9. Growing, harvesting and handling requirements

9.1 Aquaculture

Shellfish aquaculture is an important industry in many coastal areas of Canada. It is important that the leasing and licensing authorities in each jurisdiction consult DFO, ECCC and the CFIA for advice during the site approval and lease and licence granting processes. This will ensure that all considerations relating to CSSP are captured.

9.1.1 Aquaculture sites

The aquaculture of shellfish may be conducted in the following areas:

  • Where the shellfish harvest area complies with the requirements of section 4.1 Sanitary for approved or conditionally approved area classification and only when chemical or biotoxin levels do not exceed the maximum limits in the List of Contaminants and Other Adulterating Substances in Foods.
  • Where the shellfish harvest area complies with the requirements of section 4.1 Sanitary for restricted or conditionally restricted areas and only when chemical or biotoxin levels do not exceed the maximum limits in the List of Contaminants and Other Adulterating Substances in Foods. Shellfish harvested from a restricted or conditionally restricted area requires a licence issued under the Management of Contaminated Fisheries Regulations (DFO, 1990) and a decontamination plan.

    Holders of leases within restricted or conditionally restricted areas may be required, at the discretion of the CSSP shellfish control authority, to have bacteriological analyses of overlay waters and/or chemical analysis of shellfish performed by ISO 17025 accredited third-party laboratories. The analyses will be per the requirements under section 4.1 Sanitary in order to demonstrate that the bacteriological quality of the lease site overlay water has not deteriorated and that the shellfish have not been subjected to significant sources of chemical contamination.

  • Where the shellfish harvest area is not within any prohibited area as described in section 4.1 Sanitary, unless for collection of seed and/or spat, and licensed under the Management of Contaminated Fisheries Regulations.

9.1.2 Integrated multi-trophic aquaculture

For the purposes of the CSSP, integrated multi-trophic aquaculture refers to the raising of shellfish and finfish within a 125 metre radius of one another in the marine environment.

Special measures are required to ensure that the shellfish cultivated and harvested from such systems are not adversely affected by potential sources of pollution stemming from the culture operation and structures (see section 4.1 Sanitary).

The aquaculture proponent who plans to cultivate and harvest shellfish within the 125 metre distance of a finfish net pen must do the following:

  • have a documented agreement with the authority responsible for land tenure and/or licensing aquaculture activities for the exploitation of the species grown on the site,
  • have confirmation from ECCC that it has surveyed and classified the surrounding waters outside the 125m perimeter and,
  • submit an Integrated Multi-Trophic Aquaculture Management Plan (IMTAMP) to the RISC.

Failure to meet the conditions of the IMTAMP must be immediately reported to the Chair of the RISC.

9.1.3 Aquaculture methods

Proponents are to culture shellfish in a manner that will ensure they are safe for consumption before harvesting them for sale. If a shellfish control authority determines that the technology used to grow shellfish could potentially create or attract significant sources of contamination, failing to develop adequate control measures could lead to the aquaculture site being closed.

Any shellfish cultured using this type of technology must be subject to preventive controls by a licensed operator, or the leaseholder must submit a harvest plan with appropriate control measures to the regional shellfish control authority.

9.1.4 Aquaculture in land based tanks

Operators of land based aquaculture facilities are licensed, as required, by either DFO and/or the provincial licensing authority. Shellfish aquaculture conducted for the purpose of growing shellfish to market size is subject to controls to ensure food safety hazards are not introduced during the growing phase. Guidance on water supplies, water treatment and filtration, shellfish handling, tanks and plumbing systems are contained in guidance for wet storage of bivalve shellfish.

When the operator of a land based shellfish aquaculture facility is also a CFIA licensed operator, the operator shall consider the potential hazards and controls when developing and implementing a preventive control plan for this activity.

9.2 Conveyances – Vehicles and vessels

9.2.1 Vehicles

All licensed operators are to ensure that vehicles used for transporting shellfish to or from establishments are to be constructed, operated, and maintained in accordance with the applicable sections of part 4 of the SFCR. Controls for such are to be included in a preventive control plan.

9.2.2 Vessels

Operators of shellfish harvesting, handling and/or aquaculture maintenance vessels should consider the following:

  • Vessels are prohibited from discharging sewage or human waste within 3 nautical miles of the shore unless the discharge is passed through a marine sanitation device that reduces the fecal coliform count to an acceptable level Footnote 5 or,
  • Vessels have a designated human waste receptacle or holding tank onboard unless it is feasible and normal practice to return to shore to use washroom facilities.

Human waste receptacles or holding tanks are to be emptied into approved sewage systems in a manner that will not cause contamination of the shellfish or shellfish harvest area.

Vessels are expected to comply with any other relevant federal, provincial, or territorial legislation or requirements. It is the vessel operator's responsibility to inquire about any additional requirements.

9.3 Handling and identification

9.3.1 Washing of shellfish

Shellfish are to be rinsed reasonably free of sediments and detritus as soon after harvesting as is feasible, using water from approved shellfish harvest areas. Shellfish may be rinsed at the time of harvest at the shellfish harvest area.

Shellfish can only be washed in an establishment of a licensed operator when it is not practical because of harvesting methods or climatic conditions.

9.3.2 Temperature control of shellfish during transportation from shellfish harvest areas to shellfish processing establishments

Temperature of shellfish is to be controlled during transport when ambient air temperature and time of travel are such that unacceptable bacterial growth or deterioration may occur. Specific handling requirements may be prescribed by licensed operators and licensing authorities to control undesirable growth of pathogens such as Vibrio species.

9.3.3 Shellfish identification at the harvest area

Harvesters are to identify shellfish, when required as a condition of DFO licence or provincial regulation, with a durable, waterproof tag or label on each container of shellfish. Harvesters are to provide a transaction record to licensed operators when the shellfish are sold in bulk.

The harvester tags, labels, or transaction record will contain the following information:

  • the licence holder or harvester's name;
  • the most precise identification of the harvest location as is practical (e.g., Long Bay, Smith's Bay, licensed operator number or a lease number), area number and sub-area if applicable;
  • the date of harvesting; and
  • the species.

When harvesters are not required to tag or label shellfish as a condition of a DFO licence or provincial regulation, the licensed operator is then required to identify the shellfish upon receipt at a shellfish processing establishment. This is required so that the identity of the shellstock lot can be maintained throughout processing. The procedure for maintaining identity is described in the licensed operator's preventive control plan.

9.4 Wet storage or relay

9.4.1 Wet storage - shellfish harvest areas

Persons who wet store or relay shellfish must be authorized, where required, by federal or provincial authorities.

The requirements for wet storage in a shellfish harvest area are:

  • The site must be located in an area that is classified as approved or conditionally approved.
  • Shellfish may be removed from a wet storage site only when it is in open status.

9.4.2 Relay

The relay (natural or container) of shellfish to approved or conditionally approved areas can be an effective measure to reduce the microbiological contamination associated with shellfish harvested from restricted or conditionally restricted areas. The most common length of relay used is 14 days or longer. Relay periods of less than 14 days can be used but require a comprehensive scientific study to determine the effectiveness of the relay. All relay must be conducted according to a decontamination plan under a Management of Contaminated Fisheries licence.

The requirements for all types of relay include the following:

  • Shellfish relay lots are separated by at least 10 metres from other shellfish on the relay site to prevent cross contamination.
  • The relay site and relay lots are appropriately identified.
  • Any relay site that has been placed in closed status for any microbiological reason will require a new relay period which commences when the relay site is re-opened
  • Documentation is available to demonstrate each lot of shellfish has been relayed for an appropriate amount of time and that it meets bacteriological criteria noted below.

Additional requirements for relay periods of 14 days or longer:

  • Shellfish relayed for more than 14 days and less than 21 days are sampled representatively and tested to verify their acceptability.
  • Shellfish relayed 21 days or longer are not required to be tested
  • Shellfish are considered acceptable if the fecal coliform levels in a minimum of one representative sample are less than or equal to 230 fecal coliforms/100g.
  • Containers may be used as long as the containers and the shellfish loading do not restrict water flow and normal shellfish filtration activity. Shellfish are not be loaded in containers in excess of the maximum values used in depuration which includes:
    • a maximum depth of 10 cm for Manila and littleneck clams, Atlantic oysters, hard shell clams
    • a maximum depth of 10 cm for soft-shelled clams
    • a maximum depth of 30 cm for Pacific oysters

The loading criteria for other species would be determined by scientific study.

Additional requirements for relay periods of less than 14 days:

  • The process is proven to be effective by testing a minimum of 20 lots.
  • Each lot used must have an initial bacterial count greater than or equal to a geometric mean of 230 fecal coliform/100 g, with no sample less than 100 fecal coliform/100g.
  • The number and location of samples to be taken at the beginning, mid-point and end point during the relay study is shown to be statistically valid.
  • The maximum initial load is 2300 fecal coliforms/100 g unless the relay study proves otherwise.
  • After the relay study, a minimum of one representative sample is tested at the beginning and at the end of the relay period.
  • Containers do not restrict water flow and are loaded to permit normal shellfish filtration activity. This includes:
    • a maximum depth of 10 cm for Manila and littleneck clams, Atlantic oysters, hard shell clams
    • a maximum depth of 10 cm for soft-shelled clams
    • a maximum depth of 30 cm for Pacific oysters

The loading criteria for other species would be determined by site specific studies.

  • Shellfish samples that meet the bacteriological criteria for depuration are considered acceptable.
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