Officers with the Department of Fisheries and Oceans were out surveying beaches Wednesday in Nova Scotia's Digby and Annapolis counties, hoping to find answers to why thousands of dead sea creatures have been washing ashore.

The distressing amount of sea life and diversity of species found dead on some beaches on Nova Scotia's coast along the Bay of Fundy over the past few weeks has been puzzling.

In late November, thousands of herring began washing up on the shores around St. Marys Bay, not far from Digby.

Dead fish and other aquatic creatures were discovered washed up on a beach in Plympton, Digby County on Boxing Day. (Eric Hewey)

During the first week of December, thousands more dead herring turned up in the Annapolis Basin.

Then, on Boxing Day, scores of dead herring, starfish, lobster, bar clams, crabs and scallops blanketed the beach below Savary Park at Plympton in St. Marys Bay.

Many tests, few answers

Doug Wentzell, regional director general for DFO, said his agency has been working with the Canadian Food Inspection Agency and Environment and Climate Change Canada to solve the mystery.

So far, they haven't turned up any answers.

"Based on the testing that we've done to date, we haven't determined any indications of infections or infectious agents," he said.

Wentzell said there is also no evidence to indicate toxins are responsible.

"So that is good news, but we're continuing to follow up particularly with some of the other species that are materializing recently," he said.

There are still some tests outstanding, for instance tests for viruses which take time to cultivate in the lab.

Some of the things Eric Hewey and others discovered washed up on a beach in Digby County on Boxing Day. (Eric Hewey)

Highest tides, healthy ecosystem

Graham Daborn, a professor emeritus at Acadia University in Wolfville, N.S., who studies ecology in the Bay of Fundy, told CBC's Maritime Noon the ecological health of the Bay of Fundy is generally very good.

"Largely because it has such enormous tides so that there is very considerably exchange of water with the Gulf of Maine and the Atlantic Ocean and also because we're not a very industrialized region so many of the things that affect coastal waters around the world are less of a problem here, things like contamination from industry or from very large cities and so on," he said.

Now that so many different species are being found dead, Daborn said disease is unlikely to be the cause. He said it indicates something amiss in the environment.

Sightings like this on the shores around St. Marys Bay, N.S., have been a common sight since late November. (Submitted by Joan Comeau)

"One would begin to think that there is something systematic about the water that is a problem. Is there enough oxygen there? Has the temperature changed suddenly?" he said.

"There is something, I think, systematic that we would want to examine. That requires that the science community get out there and start looking closely at the water conditions in the place where this has occurred …. That could be as simple as a sudden drop in temperature but there's no evidence, as far as I'm aware, that that has happened."

Too soon to draw conclusions

Daborn also suggests recent wet weather in the province could have caused a large amount of runoff from the land which could wash large concentrations of contaminants into the ocean.

Heather Fairbairn, speaking for the province, said the Nova Scotia Department of Fisheries and Aquaculture has been closely monitoring the health of farmed fish in the area since the first reports about masses of dead herring.

She said there have been no recent reports from aquaculture operators in the St. Marys Bay about accidental discharges of chemicals or aquatic animal health issues. Provincial veterinarians last visited the area last week.

"There are a number of different theories but we're not going to speculate, at this point in terms of what may be at play here," said Wentzell.

He said it's too soon to draw any conclusions about possible causes.

"What I can say is our work over the last couple of weeks has been very much focused on the pathology of herring in particular, because that's what we were seeing," said Wentzell.

"Our attention is now starting to turn to more of a broader, ecosystem type of approach to make sure that there are no environmental or broader issues that are happening in the environment.

"I hope you can appreciate at this point that we simply do not have any evidence to rule out or confirm many of those scenarios."