Derek Blackrider, 37, went missing after he entered the Bow River at Shouldice Park for a swim on Wednesday afternoon. (Calgary Police Service)

Calgary police are looking for a man who was last seen swimming in the Bow River on Wednesday.

Derek Blackrider, 37, was with friends when he went into the river at Shouldice Park at about 5 p.m. MT.

They lost sight of him shortly afterwards.

An extensive search that included the fire department’s aquatics team and a Calgary police HAWCS helicopter did not locate the man.

Blackrider is native, five feet eight inches tall, 150 pounds and was wearing a red shirt and dark jeans when he was last seen.

Anyone with information on his whereabouts is asked to call police or Crime Stoppers.