In a series called Deep Trouble, CBC News explores the perils facing the endangered North Atlantic right whale.

Transport Canada has lifted speed restrictions in shipping lanes in the Gulf of St. Lawrence after no North Atlantic right whales were seen in the lanes.

On June 26, the federal government required ships to slow down in the shipping lanes north and south of Anticosti Island to protect the endangered North Atlantic right whale.

On July 8, the slowdown area was expanded.

But the department says despite 240 hours of flight surveillance in 44 trips over the past month, no whales have been seen in the shipping lanes.

There are only about 400 of the species left on the planet. There have been eight right whales found dead in Canadian waters since June. Ship strikes and entanglement in fishing gear have been identified or suspected in the deaths of other North Atlantic right whales in recent years.

Vessels are now allowed to travel at "safe operational speeds," said a news release from the department issued on Friday evening.

Transport Canada will continue to monitor the area, and if right whales are spotted, slowdowns will be implemented again.

The department said during the slowdown period, vessels were taking more direct routes through the Gulf instead of using shipping lanes because the speed limit was the same throughout the area. That resulted in traffic coming closer to areas where right whales are known to frequent.

By lifting the speed restrictions, the department hopes vessels will go back to using the shipping lanes and avoid areas where whales may be present.

Tonya Wimmer, the executive director of the Marine Animal Response Society, said she hopes the change does not have serious repercussions for whales.

"In light of a species that moves around so much … it is a very tricky thing just to say they are here, they stay there and we'll draw the box around them. Because they don't function that way, and therefore we shouldn't either, and we should be as precautionary as possible."

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