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Workshop on approaches to define nutrient enrichment criteria in southern Gulf of St. Lawrence estuaries

Regional Science Process – Gulf

March 8 and 9, 2011
Charlottetown, PE

Chairperson: Gérald Chaput


Eutrophication of marine systems is generally related to the runoff consequences of chemical fertilizers, burning of fossil fuels, land use changes, and wastewater discharges in coastal areas (CCME 2007). An initial consequence of nutrient over-enrichment is increased plant growth. In shallow marine environments and intertidal zones where sufficient light reaches the bottom, fast growing macroalgae such as Ulva may increase, eliminating slower growing macroalgae and sea grasses (e.g., Zostera) (CCME 2007). Excessive macroalgal growth can produce anoxic conditions within the water column, as a result of the decomposition of the macrophytes, and this can have important consequences to the ecosystem ranging from algae and aquatic plants to fish and fish habitat (DFO 2009).

The Canadian Council of Ministers of the Environment (CCME) developed the Protocol for the Derivation of Guidelines for the Protection of Aquatic Life (CCME 1991) to deal specifically with toxic substances. Nutrients were considered not to fit this model because they are, in general, non-toxic to aquatic organisms at levels and forms present in the environment. The secondary effects of eutrophication and oxygen depletion are however serious concerns and since the factors that determine the assimilation capacity of a coastal system and its response to nutrient inputs are not well understood, it was considered neither feasible nor desirable to establish generic nutrient criteria that were applicable to all types of coastal systems (CCME 2007). As such, a framework based approach that was consistent with the CCME guideline principles was recommended and that guidance framework for nutrients for the management of nearshore marine systems was published in 2007 (CCME 2007).

The Province of PEI began the process of developing nutrient criteria for Island estuaries by establishing a Regional Technical Advisory Group (RTAG) as per the guidance framework (CCME 2007). The RTAG was tasked with determining the most appropriate science based approach to develop nutrient criteria for nitrate which would reduce or eliminate the incidence of anoxic events in estuaries and bays in the province. Although nutrient enrichment appears to be a greater issue for PEI, the estuaries and bays of the southern Gulf are all susceptible to these stressors and the development of integrated ecosystem based management approaches requires consideration of all the factors which can affect fish and fish habitat.

The Oceans Division of DFO Oceans and Science has asked for science advice on approaches which could be used to develop nutrient criteria to be used in the assessment of the impact of nutrients on fish and fish habitat in bays and estuaries of the southern Gulf. The work of the PEI RTAG would be invaluable in the review of watershed specific approaches which could be considered for the southern Gulf of St. Lawrence.


The objectives of the meeting are to review approaches to develop nutrient criteria for estuaries and bays in the southern Gulf of St. Lawrence. CCME (2007) provides an overview of methods and recommended the USEPA guidelines approach (USEPA 2001) as it was generic enough to be applied to Canadian coastal waters. The review should consider the information requirements, the robustness, and the ease of application of possible approaches. Specifically, the review will consider:

  1. Overview of known impacts of nutrient enrichment on fish, fish habitat and ecosystem structure, with emphasis on the southern Gulf of St. Lawrence estuaries
  2. Review of approaches to develop guidelines from other countries
  3. Review of application of an approach to PEI estuaries and its potential application to other areas in the southern Gulf of St. Lawrence
  4. Identification of knowledge gaps and recommended further work that would lead to the development of tailored approaches for the development of nutrient criteria for bays and estuaries of the southern Gulf.

Expected Publications

The meeting will not generate advice. The review of approaches and the recommendations for further work will be documented in a proceedings report. Working papers or reports that are presented for review may be upgraded to research documents if considered appropriate. The proceedings document and supporting research documents are expected within four months of the date of the meeting.

When finalized, the products from the meeting will be posted on the DFO Canadian Science Advisory Secretariat website.


To contribute materials and to assist in the review participation is expected from:


Canadian Council of Ministers of the Environment. 2007. Canadian water quality guidelines for the protection of aquatic life: Nutrients: Canadian Guidance Framework for the Management of Nearshore Marine Systems. In: Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg.

DFO. 2009. Ecological Assessment of Irish Moss (Chondrus crispus) in Basin Head Marine Protected Area. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2008/059.

Lane, P. and Associates. 1991. Prince Edward Island Estuaries Study. Water quality in the Cardigan River, Boughton River and St. Peter’s Bay. Report prepared for Environment Canada and Prince Edward Island Department of the Environment.

Strain, P.M. and P.A. Yeats. 1999. The relationships between chemical measures and potential predictors of the eutrophication status of inlets. Mar. Poll. Bull. 38:1163-1170.

USEPA. 2001. Nutrient Criteria Technical Guidance Manual: Estuarine and Coastal Marine Waters. EPA-822-F-01-003. Office of Water.

Vandermeulen, H. 2005. Assessing marine habitat sensitivity: A case study with eelgrass (Zostera marina L.) and kelps (Laminaria, Macrocystis). DFO Can. Sci. Advis. Sec. Res. Doc. 2005/032.

Vandermeulen, H. 2009. An Introduction to Eelgrass (Zostera marina L.): The Persistent Ecosystem Engineer. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/085: vi + 11 p.


Participation to CSAS peer review meetings is by invitation only.

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