Algal bloom in Doubtful Sound not thought to be toxic

Environment Southland has been investigating reports of an algal bloom in Doubtful Sound, Fiordland and whether it was connected to reports of fish deaths.

Results from samples of phytoplankton taken at Crooked Arm, Doubtful Sound on 11 January following reports of an algal bloom suggest there is no human health risk related to the consumption of kai moana, nor recreational activities in the area.

According to the results, the blooming algae are from the Skeletenoma genus, a marine diatom not known to be toxic.

Further test results suggest that Skeletenoma are also in higher than usual numbers along the open coast of Te Rua-o-te-moko Fiordland.

There was concern that fish deaths also reported in the area at the time were linked to the algal bloom. However, due to the condition of the fish samples taken from the fish die off, the cause of death was unable to be determined and there have been no further reports of fish die offs to date.

Ongoing monitoring of the bloom situation is being coordinated with partner agencies, tourism operators and the fishing industry.