As the cruise-ship season starts to ramp up along the West Coast, an environmental group is calling on the federal government to tighten its rules and raise minimum standards around vessels dumping sewage and other waste in protected marine areas. World Wildlife Fund Canada said in a report this week that all types of ships operating in Canadian waters generate — and potentially dump — 147 billion litres of operational waste each year, the equivalent of 59,000 Olympic-sized swimming pools.