On the heels of a fish kill in two Prince Edward Island rivers, Lloyd and Donna Lewis discovered an 11-acre lease of oysters all dead at the end of July.

They said a form of seaweed native to PEI, known as Enteromorpha, took out their lease within seven short days. “We put out all new seed and went back to that bed one week later and everything was dead,” said Donna Lewis.

She said this seaweed does the same thing as sea lettuce, which is also becoming very prominent in PEI rivers and estuaries. The seaweed grows at a rate that Lewis said is “quicker than my garden.”

When it reaches its growth potential of about four to five feet, the weed lies down on the surface of the water and begins to die. As it dies it sinks to the bottom, where the seaweed sucks up all the oxygen in the river. “The event has happened and there are no answers,” said Lewis.

Agriculture runoff that contains nitrates is being blamed for the resulting devastation of the island’s streams, rivers and ultimately inhabitants such as trout, salmon, and now oyster seed. The runoff works its way down through the soil into the groundwater and eventually into rivers and estuaries, causing seemingly out-of-control amounts of sea lettuce or other invasive seaweeds to grow. Left behind for the Lewises is dead spat and a financial loss of $250,000.

“Ninety-five percent of the 11-acre lease is dead. All sizes of seed were lost,” said Lewis. This includes medium and large choice oysters, which is what the couple sells to specific specialty markets. The loss is spread over the five to six years it takes to fully produce a market size oyster.

The Lewises are not new to shellfish losses. Five years ago they were hit with Haemic neoplasia, a condition affecting the blood cells of the clams. “There used to be 15 growers on the island, now we have only one,” she said.

Department of Fisheries and Oceans (DFO) and the PEI Aquaculture Alliance investigated the clam disaster. Samples taken didn’t show anything concrete.

Dr. Greg McCallum, a science technician with the Department of Fisheries and Oceans DFO in Charlottetown, the island’s capital city, was on site at the Lewis lease at 10 a.m. the day the dead oysters were discovered, to take samples. All samples were sent to the DFO lab in Moncton, New Brunswick, for testing. “When we take samples, we rule out disease. In the case of Donna and Lloyd there was no disease, but that’s just one piece of the puzzle,” McCallum said.

Richard Gallant, Deputy Minister of Fisheries and Aquaculture, whose department assisted with the investigation into the Lewis oyster lease kill, indicated his agency has been working with the Canadian Council of Fisheries and Aquaculture Ministers (CCFAM) to address the need for an aquaculture framework agreement across Canada. “This would be a federal/provincial industry program that might contain some kind of “crop insurance” similar to what land-based owners would have,” says Gallant, adding that in the Lewis case, where “smothering” occurred due to excessive amounts of seaweed, there is a lack of clear program support.

The CCFAM is a forum that meets annually to discuss joint initiatives and establish a number of task groups to complete work on certain issues.

Gallant said over the past number of years, the province has been investigating a number of losses in the aquaculture industry, including an invasive tunicate in the mussel industry and now the Lewises’ oyster loss. The Deputy Minister noted they are trying to make these issues a priority. “There is a need for such an agreement between the federal and provincial governments.”

For Lewis it couldn’t come soon enough.

She compares the Prince Edward Island shellfish industry to what happened in Chesapeake Bay area of Maryland ten years ago. “They were hit with an agriculture bacteria called psisteria and scientists studying it declared a state of emergency,” recalled Lewis.

A one-time shellfish columnist for a PEI newspaper, Lewis said she has been “preaching” the message for 10 years to the agriculture community with regards to runoff and believes she and her husband, Lloyd, were never taken seriously. “It’s all coming to fruition now. It’s really sad to see the lease destroyed right before our eyes,” she says and adds that shellfish leases have been in the Lewis family for five decades with continued expansions over those years.

Trying to make sense of what has happened, Lewis says it’s not easy when there is no explanation. “Just no disease, no oxygen.”