At least 15 sharks would have been deemed an imminent threat needing to be killed this week under the Barnett Government's new shark policies aimed at safeguarding ocean users.
An analysis of shark sightings catalogued by Surf Life Saving WA shows that several sharks spotted almost daily this week may have triggered expanded catch-and-kill provisions.
Under the Government's new "shark hazard mitigation" policy, two specially monitored zones will be declared off the metropolitan and South West coastlines between September and April.
The areas will extend to the edge of State waters three nautical miles offshore and will see "arrays" of drum lines - floating baited hooks anchored to the ocean floor - set up 1km from the shoreline.
Announcing the measures on Tuesday, outgoing fisheries minister Troy Buswell said commercial fishermen would also be expected to catch and destroy sharks bigger than 3m if they saw them within the zones.
"These are significant changes to our previous policy," Mr Buswell said.
According to SLSWA, using help from the Fisheries Department, there were more than 15 instances since Monday in which sharks 3m or bigger were spotted inside those zones.
They were primarily bronze whalers and tiger sharks - both of which have been known to attack humans - although other sharks were unidentified in terms of species or size.
There was also a 4-5m shark of an unknown species sighted at Moses Rock near Margaret River yesterday.
Others, including a "large great white shark" off Middleton Beach in Albany, were seen in areas that will fall outside the new catch and kill zones, or were too small to be considered a sufficient threat.
New Fisheries Minister Ken Baston confirmed that any shark seen within a "marine monitored area" that was bigger than 3m and considered dangerous, including bull sharks and tiger sharks, would be targeted.
Conservation Council of WA director Piers Verstegen said killing sharks bigger than 3m was arbitrary and "bizarre" and the Government's inability to provide detail showed the policy was rushed.
"The whole idea of hunting down individual species that migrate thousands of kilometres just because they come into a particular zone and don't necessarily pose any risk doesn't make sense," Mr Verstegen said.
Shadow fisheries minister Dave Kelly said he understood the pressure the Government was under to protect people but wanted it to release the research used as the basis for the new policy.
Mr Kelly also questioned the merits of drum lines.
He said that up to 60 per cent of the sharks that drum lines had killed in Queensland over the past two years were smaller than 2m.