A grieving Manitoba father who says his son drowned when he became entangled in seaweed wants beach-goers to be warned about the potential perils of what’s growing in the water.

Mervin Dueck says his 19-year-old son Calvin drowned at the St. Malo Beach in southeastern Manitoba two years ago, after he got trapped underwater in seaweed.

There is no mention of seaweed in Calvin’s official cause of death, but his father wants that changed.

Calvin was swimming with friends at St. Malo Beach, and at one point, Dueck says, his son decided to head back to shore. He never made it.

“On his way back he got tangled up in seaweed and went down and never came back up again,” Mervin told CTV Winnipeg.

Calvin’s death was ruled a drowning, Mervin said. There was no mention of seaweed as a cause.

Mervin says two years later, he struggles with his son’s death. “There’s always that empty hole there.”

He now wants the tracking and reporting of a drowning changed to highlight seaweed as a possible hazard.

“What else are you going to attribute it to?” Mervin said.

Manitoba’s Chief Medical Examiner’s Office says it won’t include contributing factors of a death unless the evidence is crystal-clear.

Christopher Love, a coordinator at Lifesaving Society Manitoba says it’s not easy to determine if seaweed is the reason a person drowned.

“A body that was entangled in weeds might be pushed away from those weeds by the time it’s discovered, or that may have been a factor that just is not clear because the person wasn’t actually entangled when they were found,” Love said.

Mervin says he wants the dangers of seaweed included in swim lessons too. He says, while his son was a strong swimmer, he was not familiar with what can lurk below in a lake.

However, the life-saving society says it’s open to the idea of raising awareness.

“That might be (included) in swimming lessons in the future, it might be in additional TV spots or radio spots or brochures,” Love said.

The province says the beach at St. Malo is monitored daily and that seaweed is trimmed when necessary.

With a report by CTV Winnipeg’s Jeff Keele