The Friends of Port Mouton Bay gather at a rally held on Carter's Beach March 18, 2007.(RD photo)

by Jennifer Ford
At the end of March, the province of Nova Scotia announced its purchase of Carter's Beach in Queens County. It's a very popular white sand beach and a nesting area for the endangered Piping plover. Earlier that week, I had been looking at pictures of Carter's Beach on the website of the Friends of Port Mouton Bay (FPMB). Anyone who has driven through the area of Port Mouton in the last two years will have seen Friends of Port Mouton signs and bumper stickers.
The FPMB is a group of volunteers formed to protest the proposed expansion of a salmon farm in the Bay. Currently, there is a salmon farm near Spectacle Island (see map, page 31), which raises about 200,000 salmon at a time. If a new site at Port Mouton Island is approved, the two sites together will be the largest salmon farm in Nova Scotia, raising between 200,000 and 600,000 salmon at a time.

Fish farm cages at the current site looking out from Carter's Beach. If the expansion is approved, the two sites together will be the largest salmon farm in Nova Scotia. (D. Alex Ross photo)

The FPMB believes the existing salmon farm has had negative impacts on the habitat of the Bay, the lobster fishery, and Carter's Beach. The photos of Carter's Beach I was looking at just before the province announced its purchase show mats of algae washed up on the beach. Long-term residents say these are very unusual and attribute the algae to nutrient enrichment caused by the salmon farm, which can easily be seen from the beach.
For several years, I studied the impacts of salmon farms on Wild salmon, and there is now a large body of research on the effects of salmon aquaculture on Wild salmon and trout. There is also a lot known about the impacts on the plant and animal communities directly below the cages. But that's really all. Research of any kind about the impact of fish farms on other species of fish, invertebrates, or plants that share the same environments is almost completely lacking.
When a community member wants to know what impact a fish farm might have on lobster stocks, herring that migrate through the area, or nearby clam beds, there is almost no information to guide them. So when I first saw the FPMB website, I was impressed. The site includes a detailed look at the impacts of the salmon farm on other industries and users of Port Mouton Bay, and impressive "citizen science" describing the environmental impacts of the existing farm and the likely impacts of the proposed expansion.
At salmon farms, the fish are kept in net pens up to 30 meters in diameter, each of which holds around 25,000 fish. Feces and uneaten food is released directly into the ocean. Research by the FPMB indicates that the existing salmon farm (one third of the maximum production that is being proposed) produces about the same volume of waste as 1,000 people and the same amount of nitrogen as 10,000 people.
For comparison, there are about 12,000 people in Queens County. Ideally, currents and waves disperse the waste from salmon farms enough to prevent any negative impacts. But if there is not enough flushing, wastes build up on the seafloor. The area becomes covered in fine sediments and often becomes anoxic (low-oxygen). This kills or repels many types of seafloor creatures, so diverse bottom communities get replaced by communities consisting of a few tolerant species, mostly worms and bacteria.

(1) The current site off Spectacle Island in Port Mouton Bay. (2) The proposed location of a second site near
Port Mouton Island. (Map courtesy of Friends of Port Mouton Bay)

A CLOSER LOOK
Oceanographers and Port Mouton residents Ron Loucks and Ruth Smith combined their expertise and experience with that of area fishermen to investigate the effects of the existing salmon farm. They have looked at the bathymetry of the area and seen that the proposed salmon farm sits in a basin, largely enclosed by an underwater sill (see map). Lobster fishermen volunteered boat time to deploy drogues and seabed drifters at the current and proposed salmon farm sites, to track the currents in the bay.
Drouges have an underwater "sail," so they follow currents at a set depth below the water, while seabed drifters float just above the seafloor. The drogues floated in a roughly circular pattern, indicating the water (and the fish farm waste) was not really leaving the harbor. Other area residents walked along the shorelines to look for seabed drifters. After a strong northeaster in April, some of the drifters showed up on the beaches, suggesting that currents could sometimes carry the fish farm waste onshore.
This lack of flushing also explains the observations of experienced divers who volunteered to look at the areas surrounding the salmon farm in the Bay. They found accumulations of loose organic sediments 30 to 90 cm deep that they believe are at least partly made of salmon farm waste, in an area of approximately 80 hectares around the existing salmon farm. The province also monitors environmental conditions at salmon farms, and has documented anoxic conditions at the salmon farm in Port Mouton on several occasions.


Local fisherman Eugene Broome takes part in a rally on March 18, 2007 at Carter's Beach. (RD photo)


Provincial monitoring is supposed to ensure that if habitat problems occur, they are quickly remedied, but that doesn't seem to have happened in Port Mouton.
The lobster fishery is by far the important fishery in the area, as it is in most of Nova Scotia. There are about 40 active lobster boats in Port Mouton, which traditionally fish in both the area currently used by the fish farm at Spectacle Island, and the area that will be taken over by the proposed farm at Port Mouton Island. In fact, a study of lobster landings from 1946 shows a lot of fishing activity in these areas, particularly the area inland of Port Mouton Island, where the proposed salmon farm would go.
Several of the men involved in that survey are the grandfathers or great-grandfathers of lobster fishermen who fish there today. The knowledge of the marine environment accumulated by generations of fishermen has been key in determining what changes have occurred since the salmon farm was established, and the FPMB has collected this information with surveys and interviews. It's difficult to get this type of knowledge included in environmental assessments, but it represents the largest and longest-term set of observations of the area.
There is also some evidence that the basin west of Port Mouton Island serves as a nursery area for lobsters. Lobster fishermen and other FPMB members conducted a scientific survey of lobster catches throughout the Bay, recording how many lobsters were caught near the existing and proposed salmon farms, and in other parts of the Bay. The survey found more than twice as many egg-bearing females in this basin area than in other areas, showing that female lobsters bearing eggs tend to spend time in this area.
The Lobster Conservancy of Maine has found that the most productive lobster nurseries match the layout of this basin ­ a southwest-facing cobble beach connected by a half-submerged bar to other islands creating a "catcher's mitt" facing into the summer winds. After hatching from eggs, lobsters swim around in the water column until they're one or two centimeters long, after which they settle to the bottom and spend several years in a very small area. These nursery areas where settled lobsters live have been shown to be important to their survival and recruitment.


Seabed drifters (left) and drouges (right), released at both the current and proposed sites, tracked currents in the Bay. The data collected shows that most water (and fish farm waste) remains in the harbor, and suggests that waste is also often washed up on shore at nearby beaches. (Photo courtesy of Friends of Port Mouton Bay)

Port Mouton fishermen report commonly finding juvenile lobsters in the area to the west of Port Mouton Island. Fishermen lose direct access to areas when aquaculture leases are given, but if the area is an important nursery area for a commercial species, then the impact of the loss will be much larger than just a 70-hectare lease.