Researchers at the University of Montreal have modelled the routes of both whales and boats in the St. Lawrence Estuary to prevent a collision course between the two — an encounter that often proves fatal for the marine mammals, many of which are endangered species.

Although there is little data on the actual number of collisions, "many quasi-collisions are reported and these accidents are a threat to the recovery of certain species," said Clément Chion, a PhD student who helped model the whale software.

Vessels often don't realize they've collided with a whale, because carcasses sink, Chion said in a news release about the program.

"To reduce the risk, we can play on two factors: the speed of the cargo ships and their trajectory," he said.

Software considers whales, industry needs

The computer program simulates the travels of five mammal species — minke, fin, beluga, humpback and blue whales — and the routes of three types of boats — recreation, excursion and cargo — while factoring in human behaviour and changing environmental conditions.

The software weighs several variables, including the number of boats and whales, where they travel, the currents, the tides, and the weather.

Researcher Lael Parrott said the software aims to reduce collision risks "while taking into account the impact on industry and marine transportation."

Parrott led a research team at the Complex Systems Laboratory that modelled the software.

Parrott's team studied nine scenarios based on real conditions observed in the estuary since 1994. They also interviewed vessel operators to understand their navigational decisions.

Plotting safer routes isn't straightforward. For instance, a three-kilometre cargo ship detour would avoid the north coast and the marine park.

But that same route would bring vessels closer to the fragile beluga whale population that swims in the centre of the river and close to the south coast.

Software researchers recommend slower speed limits

Researchers on the project also suggest boating speed limits be reduced from the current 25 knots (46 km/h) – a speed at which all collisions are always fatal for whales – to a less threatening 10 knots.

Most of the Saguenay Fjord in Quebec and part of the St. Lawrence Estuary at the junction of the Saguenay River were given marine park status in 1998 in order to safeguard the biological diversity of the area.

Whales use the marine park area – where fresh and salt water meet – as their main foraging grounds. At least 13 species have been reported in the area, with half of them considered endangered.

Parks Canada and Fisheries and Oceans Canada, which requested the software, will use the resulting models to weigh the economic and ecological repercussions of different policy decisions.