HALIFAX, Nova Scotia — Fisheries officials in Canada say weeks of testing have failed to point to an environmental problem as the cause for thousands of dead herring and other marine creatures washing ashore in western Nova Scotia.

Kent Smedbol, manager of population ecology for the Department of Fisheries and Oceans, says while the lack of an obvious cause is perplexing, he doesn’t personally believe there is cause for concern at this point.

Smedbol says scientists conducted testing on the Bay of Fundy on Thursday and preliminary results for temperature, salinity and dissolved oxygen came back normal. A camera scan of the bottom of St. Marys Bay also showed normal conditions and an abundance of live lobster in the area.

To date, Smedbol says scientists have not turned up evidence of disease, parasites or toxins.

Fisheries officers were on beaches in the St. Marys Bay area Wednesday, collecting samples as their investigation expanded beyond the herring that first appeared a month ago. A retired scientist says photos showing lobsters, starfish and clams washed ashore in western Nova Scotia could be linked to tens of thousands of herring deaths in St. Marys Bay

“We’re seeing multiple species throughout that area. We started to see them late last week … but over the last 48 hours, we’ve been seeing more significant reports,” said Doug Wentzell, regional director of fisheries management for the Department of Fisheries and Oceans.

Since late November, dead herring have been found in a 60-mile swath from St. Marys Bay to Tusket, with most found between the mouth of the Sissiboo River and Plympton.

More recently, scores of starfish, clams and lobster have also littered the shoreline and a dead whale also washed ashore on a beach in Whale Cove. Derreck Parsons, a senior compliance program officer for the Department of Fisheries and Oceans, said surveys don’t show any new die-offs or actively dying fish.

But the investigation continues.

Alain Vezina, director of science for the Department of Fisheries and Oceans, said he is in the process of contacting officials at the U.S. National Ocean and Atmospheric Administration and in the United Kingdom to seek potential help.

Ted Leighton, an adjunct biology professor at Nova Scotia’s University of Sainte-Anne, has compiled more than 40 sightings of dead herring since late November. The herring deaths were cause enough for concern, Leighton said, but now that new species have surfaced dead, it’s time to figure out “what’s really going on.”

“We’re kind of in the dark, not from lack of trying, but from the complexity of the case,” he said.

Leighton said that until scientists know what’s killing the herring, it’s hard to say whether other marine life could be vulnerable to the same forces.

“They may or may not be related,” said Leighton. “If they are related, they may be related in sort of an indirect means … (like) different pieces of global warming.”

A starfish, a lobster and a herring have very little in common, said Leighton, and it’s unlikely that an infectious disease, which targets a narrow range of organisms, could wipe out such a diverse cross-section of marine life.

Marine wardens who patrol Cobscook Bay, which opens into the Passamaquoddy Bay within the Bay of Fundy, have reported no similar die-offs in Maine. There was a minor die-off of pogies in Casco Bay in August.