The ongoing consequences of a harmful algal bloom in South Australia are still being assessed on the Yorke Peninsula. Marine biologist Stefan Andrews has noted a significant decline in fish diversity in the region. Recent government water tests indicate that levels of the harmful algae species, karenia, have decreased along much of the coastline, including Port Hughes.
In Port Hughes, a popular location for fishing, the effects of the algal bloom remain evident. Andrews remarked that the vibrant colors once characteristic of the area are now absent. While fish are still present, their diversity has notably diminished, leaving the environment looking depleted and lifeless.
Andrews has been actively diving and filming the underwater ecosystem near Port Hughes since elevated algal levels were first observed in late March. He expressed concern over the damage inflicted even at lower concentrations of harmful algal species. Observations, particularly around submerged structures like pylons, reveal a stark contrast in ecological health, with many marine organisms appearing unhealthy and sluggish.
According to the Department of Primary Industries and Regions, karenia levels were first reported at the Port Hughes jetty on March 30, 2026, peaking a week later at 16,850 cells per liter, a level categorized as elevated by the South Australian government. Latest water samples taken on April 29 indicated a decline to 1,936 cells per liter.
Despite the reduction in algal levels in certain areas, Andrews cautioned against assuming that the bloom’s effects have subsided completely. He emphasized the long-term impacts on the ecosystem and the persistent uncertainty regarding future algal blooms, as the potential for recurrence remains.
In light of the algal bloom, Thomas Hams, owner of Port Hughes Fishing Charters, reported a significant drop in business over the past months compared to the previous year. Many customers are hesitant to venture out on the water due to fears associated with the bloom and the restrictions imposed. A ban on southern calamari fishing has been enacted for both commercial and recreational boats in the Spencer Gulf and Gulf St Vincent, coinciding with a closure for King George Whiting until July 31.
While some fish species like snapper remain abundant, Hams has observed a decline in calamari populations. Patrons on his recreational charters frequently inquire about the effects of the bloom, reflecting a general apprehension among potential customers. He noted that while his business has not suffered dramatically, the rising fuel prices have posed additional challenges.
Luke Pridham, who operates the Port Hughes General Store and tackle shop, shared that misconceptions about the bloom’s spread have adversely affected tourism. Despite the bloom’s presence in certain areas, he reported that his store experienced one of its busiest Easter periods in three years, attributing the downturn in business more to fuel prices than the bloom itself. He expressed relief that their operations have not been significantly impacted so far, although he remains cautious about the potential unseen damage to the marine environment.
