Environmental Concerns

 
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ECOSYSTEMS ARE COMPLICATED

For a more comprehensive discussion of our environmental concerns (with detailed sources and references) please see the “Environment” section of our paper “Reflections on the proposed oyster farm in Antigonish Harbour”. Following is a recap of some of our major points.

ANTIGONISH HARBOUR IS AN ESTUARY.

Antigonish harbour is a shallow, and delicate estuary that is home to a variety of species:

  • Eelgrass (DFO ecologically significant species); piping plovers (NS endangered species); American eel (IUCN endangered species); and salmon, trout, bass and smelt (NS restricted fishing species).

  • Dunn’s beach and Mahoney’s beach are protected beaches and are proposed as a provincial park. Clearly, there is significant interest in protecting the harbour’s environmental integrity. Approximately 27 acres TPCI’s proposed lease #1444 is located in the protected zone around Dunn’s beach intended to protect endangered species like the Piping Plover.

  • Antigonish harbour is comparatively little studied.

  • Mr. Porter’s primary environmental argument is based on the notion that oysters are filter feeders, they will clean our water and make the harbour better. In some cases oysters have have had positive impacts on polluted waters with heavy metal concentrations, sediment concentrations and/or nutrient loading that results in eutrophication. We’ve seen no evidence Antigonish Harbour has these pollution problems ……or would benefit from the addition of millions of new oysters and related gear. In fact, the addition of these extra oysters on these leases may be harmful to the harbour.

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We are concerned that:

  • Removing nutrients that are not excessive, including metal micronutrients, could affect other species that need these to thrive

  • A change in nutrient content is concerning for suspension feeders such as the migratory fish (e.g. american eel, salmon, trout, bass, smelt), that depend on a healthy estuary ecosystem to transition from fresh water to the ocean as well as the terrestrial species (e.g. great blue heron, bald eagle, common loon, various goose and duck) that feed in the estuary

  • Interference in the nutrient content of the water and deposition of oyster feces on the sea bed have potential to alter the balance between suspension and bottom feeders

  • Cleaner water’ is a seductive concept, however if the water is already clean, supporting a diversity of life, we do not know what removing nutrients may imply for other aquatic life.

  • Perfectly clean water would support no aquatic life at all.

THE IMPACT ON EEL GRASS

Everyone agrees eel grass is vital to the health of our harbour.

  • There is good scientific evidence of the negative impact of oyster baskets on eelgrass, primarily through shading. Department of Fisheries and Oceans is currently researching this topic.

  • An additional threat to eelgrass comes from sinking oyster baskets to weather the winter – DFO is also currently researching this.

LACK OF BASELINE DATA ON ANTIGONISH HARBOUR

  • The biophysical characteristics of the ecosystem is not widely understood..

    • Worse, because there is so little baseline data on the biophysical characteristics of the harbour now, it will not be possible, even with a rigorous monitoring program, to evaluate any environmental impact relative to pre oyster farm conditions if critical baseline information is not gather prior to approval and implementation.