There are still no definitive answers on what’s behind a large fish kill in Nova Scotia, fisheries officials said during a resources standing committee meeting in Halifax on Thursday.
Dead herring started appearing along the shores of western Nova Scotia late last year, prompting biologists to look into possible causes.
At the meeting, the Department of Fisheries and Oceans Canada (DFO) said they were notified of fish appearing along St. Marys Bay Nov. 22 and sent officers to collect samples the next day. They said the National Environment Emergencies Centre was also notified.
Since then, dead herring have been found along a 100-kilometre stretch of coastline from St. Marys Bay to Tusket, N.S. Most were found within a 20-kilometre range of St. Marys, officials said.
DFO worked with the Canadian Food Inspection Agency (CFIA) and Environment and Climate Change Canada (ECCC) to carry out lab tests and analysis of the samples for infection or disease, toxins and water quality. But tests found no infectious or viral agents or toxins, and oxygen measurements of the surface and bottom of the ocean also showed normal levels.
Alain Vézina, regional director of science for DFO, said with several contaminants ruled out, there may be another environmental reason for the kill.
“We have ruled all that out and what’s left really is some sort of environmental event that would be a confluence of fish behaviour,” Vézina said. “Why are the fish in the bay? There’s a lot of fish in the bay for this time of year, which is a bit unusual.”
ECCC also tested for pesticides, metals and other contaminants, but all came back negative.
“From time to time, these things crop up,” said DFO regional director general Morley Knight.
Lenore Zann, NDP MLA for Truro-Bible Hill-Salmon River-Millbrook, questioned if toxic algae could be a factor, but Vézina said no samples that were collected showed signs of that.
Vézina said the fish kill was a “beach event” and looked like an environmental incident, but said there has still been no evidence as to what killed the fish. He added that though a small earthquake happened in December off the coast raising questions of it as a possible cause, there would be dead fish on the ocean floor as a result, not just onshore.
Progressive Conservative MLA Chris d’Entremont (Argyle-Barrington) asked DFO whether the event might have an impact on the fishing industry. They said they did not expect to see any economic impact or harm to the reputation of the industry.
Zann also asked about a dead humpback whale that had washed up in the same area on Whale Cove near the end of December. Vézina told MLAs at the meeting the whale was not connected and it appeared to have died a long time before the herring did.
Starfish, clams, and lobsters that also turned up dead along the shores were the result of a “weather event,” Vézina said.
Since Jan. 2, officials said there have been very few reports of dead fish washing up along the shores, but they are continuing to monitor the area for any new cases.
Future monitoring was questioned by NDP MLA Sterling Belliveau (Queens-Shelburne), who asked whether having a monitoring program in place before the kill would have given officials a better chance of finding out what happened.
“My point is, if there was this basic monitoring in place, prior to that, you would have a baseline of data to say ‘this is what happened,'” Belliveau said.
But Vézina said there’s no way to know that. He also said a monitoring program would require the involvement of different levels of government and it would not be feasible.
“It would be very hard to have a monitoring system at that fine scale everywhere in Nova Scotia that it would be there when the event happened,” Vézina said. “That would be extremely difficult.”
Belliveau acknowledged federal cuts to science in the last decade could have made monitoring difficult, but asked DFO how it would spend the $200 million in new funding announced in September. Vézina said the funding is nationwide, but they are trying to hire new employees and purchase new technology.
The Queens-Shelburne MLA added he’s “taken aback” by comments it is a “local event” as he said similar situations are happening in other parts of the world.
READ MORE: Dead herring washing ashore in Nova Scotia
Vézina said DFO acknowledges that and are now doing research to determine what fish may be more vulnerable to climate change.
“We know that the ocean is changing,” Vézina said.
He said there is still the possibility fish kills could happen again.
“We don’t know whether there are any trends and the frequency of these events, we have no evidence to say if and when it will reoccur and especially where,” Vézina said.
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