Police responded to reports of gunfire at about 11 a.m. Tuesday and found a 52-year-old man had been shot and seriously wounded outside the coffee shop.
Const. Brian Montague said police officers challenged the alleged shooter and exchanged several shots.
He said officers pursued the suspect, who was on a bike, but were confronted by the man on the sea wall at Science World, a popular tourist and family attraction, where there was a second exchange of gunfire.
He said police have yet to determine a motive for the first shooting.
”We don't have any real facts as to why the shooting took place," said Montague. "I don't know if the suspect is known to us. The pursuit took place both on foot and on bicycle.”
He said the victim remains in hospital in stable but critical condition.
Montague said the alleged shooter was taken to hospital in serious condition and remains under police guard.
He said a female officer was injured by flying glass and was taken to hospital with minor injuries, treated and released.
Lucas Deharo, of Vancouver, said he got a text from his wife who was inside Science World, as were dozens of children, parents and caregivers.
He said his wife told him she saw an officer shooting, and that she was told to keep calm and lay down on the floor.
Deharo said he jumped in his car and raced to the scene.
Science World announced later in the day that it had closed to "support police investigations."
Vancouver Mayor Gregor Robertson thanked police officers for their fast response to the shooting.
"This incident was a brazen attack in broad daylight, and gun violence of any kind will not be tolerated in the City of Vancouver," he said in a statement.
"I know this has been very upsetting for the many people who witnessed the attack, and for those who live and work in the neighbourhood. My thoughts are with the victim, the injured officer, and their friends and family during this difficult time."
Robin Plomp of the Independent Investigations Office, a police investigation agency, said six investigators have been assigned to the file and they have to interview many witnesses.
"Those witnesses have been taken to different locations and hopefully we’ll try and get through all of them today," said Plomp.
Plomp said once the office has completed its investigation, it will submit the file to its chief civilian director for review.
Gunfire also erupted on the streets of Vancouver on Sunday night. A 28-year-old woman was shot outside a gas station, while she and her male companion stood outside their vehicle.
The woman remains in hospital in stable condition and the man, who sustained minor injuries, fled the scene and was arrested on an outstanding warrant.
Police described that shooting as a targeted hit.
(CKNW, News 1130)