Colourful algae outbreak sparks warnings across northern NSW

An outbreak of marine algae along the North Coast and its river tributaries has caused concern as tourists flock to the region. Here’s why it’s happening.

An algal bloom in Evans River during the peak holiday season. Picture: Jenny Uebergang

An outbreak of marine algae along the North Coast and its river tributaries has caused concern as holidaymakers flock to the region in droves.

Warnings have been issued by authorities stretching from Tweed Heads in the north to as far south as Evans Head.

Residents and visitors of affected local government areas have been warned not to eat mussels, prawns or crayfish from algal bloom sites, or to drink the water.

Uneasy locals in Evans Head posted photos on social media wanting the algae identified.

Some claimed they had seen blooms start in the drain behind the town’s ambulance station and spread all the way out to the river.

Some northern NSW residents believed the algae was coral spawning or pollution, but councils soon knocked those theories on the head.

Some people believed the algae was coral spawn or pollution. Picture: Scott and Simone Barker

Marine algae, or trichodesmium (a type of blue-green algae) is a natural occurrence in tropical and subtropical ocean waters, a Richmond Valley Council spokesman said.

It is commonly referred to as sea sawdust, red tide and sea scum.

The algae can become beached, resulting in a putrid, almost ‘fishy’ smell along the beach and shoreline.

The blooms can be washed off skin under running water and are generally harmless.

However, the algae can deplete the oxygen content of the water, causing death to aquatic animals, and potentially irritating some people’s skin.

Ballina Shire Council acting co-ordinator Public and Environmental Health Kristy Bell said the council has investigated reports concerning algae at North Creek, Ballina Island, West Ballina and The Spit.

“These blooms don’t look particularly nice but they are naturally occurring and will dissipate as the weather, tide and wind changes,” she said.

The situation at Evans Head. Picture: Scott and Simone Barker

“Blooms can often be mistaken as an oil slicks or other sources of pollution and may have a strong odour.

“In later life stages, blooms will turn Pink, purple or green in colour. Locally, these blooms are demonstrating all these colours.”

Tweed Shire Council reported the algae in the lower reaches of Cudgen Creek.

Marcela Lopez, senior program leader Environmental Health, said the algae was more likely to bloom in local waterways from August to April, but can occur at anytime.

“As the temperature rises, we often see trichodesmium along the Far North Coast at this time of year,” Ms Lopez said.

“While the direct risk to human health is very low, we encourage people to avoid wading, swimming or surfing in water where a bloom is visible and keep animals away.”

Algae at Evans Head. Picture: Scott and Simone Barker

The council warned people not to eat shellfish and to not use affected water as a potable supply.

“If you come into contact with the algae, rinse it off with soap and freshwater as soon as possible,” Ms Lopez said.

Trichodesmium is a member of the phytoplankton family and plays a role in the aquatic food chain.