The 10-kilometer (6.21 miles) stretch coast of Manari, north of Broome found an estimated 17,500 dead fishes. It is believed that the fish kill occurs naturally and not by pests or by some marine diseases.

Western Australia's beaches where the dead fishes were found have more than 37 fish species. Pictures of sea turtles and sea snakes were also uploaded to social media by some locals.

"So far the evidence suggests it could be culmination of environmental factors, including high land and air temperatures, higher than normal water temperatures, a week of consistent onshore winds, and also the large spring tides we were having at the peak period of the fish deaths," said Peter Godfrey, regional manager of Department of Fisheries.

Most fishes affected were mainly those small species with more than 30 centimeters (11.8 inches) long with a record of 3 percent, added the Department of Fisheries spokesperson.

Other dead marine animals were found along the coast of Willie Creek and Cape Bertholet. The department believes that the fish kill had passed and no fresh death or dying fish was seen as of Sunday.

The increase of water temperature along with the warm weather and onshore winds found to be a huge factor in the fish kill spread and seen in the coastlines. Most fishes that are affected of the fish kill are those near-shore fishes namely Spanish flag, Leatherjacket, and Northwest snapper .

The department have already sent samples of fishes and water to its fish health unit and specialist interstate laboratories for testing and results expected in the weeks coming. They added that it's advisable for the residents not to consume nor touch the dead fishes on the shore.

Broome's Manari coast is well known for its locals to go for outdoor activities such as fishing, swimming and camping.

Photo: Deidre Woollard | Flickr