Marine Heatwave Kills 30,000 Fish, Threatens Ningaloo Reef

KARRATHA, Australia — A marine heatwave along Western Australia’s Pilbara coast has caused the deaths of an estimated 30,000 fish, with environmentalists warning of potential damage to the iconic Ningaloo Reef. The fish kill, spanning 9 kilometers near Gnoorea Point, 50 kilometers southwest of Karratha, is believed to be linked to prolonged thermal stress caused by unusually high water temperatures.

The Western Australia Department of Primary Industries and Regional Development (DPIRD) reported that nearshore waters along the Pilbara coast are currently around 31°C, 2-3°C above normal for this time of year. Nathan Harrison, DPIRD’s executive director, stated, “A warmer ocean off WA during 2024 has preconditioned a high marine heatwave risk scenario for the summer months.”

Last week, DPIRD issued a category 2 marine heatwave warning for the north coast and Gascoyne bioregions, where sea surface temperatures are 4-5°C above the long-term average. The overheated waters threaten not only Ningaloo Reef but also Exmouth Gulf and Shark Bay, raising concerns about coral bleaching and ecosystem damage.

Mardudhunera woman Raelene Cooper, a Karratha resident and Murujuga traditional custodian, described the fish kill as “upsetting.” She noted, “The water is so hot – it’s like the water that’s coming out of the shower.” Cooper’s observations highlight the immediate impact of the marine heatwave on local communities and ecosystems.

Marine heatwaves, which can last from days to months, have devastating effects on marine life. The 2010-11 marine heatwave in WA resulted in significant losses of seagrass and kelp, impacting fisheries and marine habitats. Scientists attribute the increasing frequency and intensity of such events to human-caused global heating.

Bill Hare, CEO of Climate Analytics, emphasized that marine heatwaves can trigger “extreme events, which then create a bigger environmental mess.” Meanwhile, Mia Pepper, campaigns director at the Conservation Council of WA, criticized the WA government’s recent approval of a 50-year extension for Woodside’s North West Shelf gas project, one of Australia’s largest CO2 emitters. “The timing and location of this fish kill should raise eyebrows,” she said.

Paul Gamblin, WA director of the Australian Marine Conservation Society, echoed these concerns, calling for greater accountability from government and industry. “There’s a huge dissonance between what we’re seeing in the water and what governments are approving,” he said.

As Western Australia continues to experience extreme heat, with temperatures reaching record highs, the marine heatwave serves as a stark reminder of the urgent need to address climate change and its impacts on marine ecosystems.