Thousands of fish have been released into Cockburn Sound, south of Perth, after researchers harvested pink snapper eggs and successfully hatched them in tanks.

Researchers dredged the sound late last year and collected more than 100,000 eggs, which were taken to a hatchery in Fremantle.

By a stroke of luck, the eggs were harvested just weeks before an algal bloom killed thousands of fish in the area.

A crowd-funding program was launched by Recfishwest to pay for the fish to be hand-reared.

It raised $36,000, which was $11,000 more than Recfishwest initially hoped for.

Dozens of people turned out to release about 2,000 fish from the shore on Saturday.

Another 3,000 were released further out to sea via a tube attached to a tank onboard a truck.

About a week ago, 48,000 fish were released into the area and another release is planned for later this year.