The Corporation des pilotes du Saint-Laurent central, which represents the pilots that guide the ships in our region, previously conducted an analysis of this and came to the conclusion that 95% of ships were complying with the recommended voluntary lower speed limit.
In my area, that speed limit is helping to reduce shoreline recession rates but hasn't stopped the erosion. Instead of losing two metres a year, we may lose just one where a speed limit is in effect. The limit applies on only certain sections of the river. It's a commendable measure but, on its own, won't be enough to protect riparian habitats.