Last week, DPIRD issued a marine heatwave alert for the North Coast and Gascoyne regions with the potential for it to reach the southern half of the State over the next couple of months.
This follows current sea surface temperatures in the North Coast region of the State being recorded 4 to 5°C above the long-term average, while surface sea temperatures in the Gascoyne region are currently 2 to 3°C above its long-term average.
Fisheries officials believe this current marine heatwave is the most likely cause of mass fish deaths off WA’s Pilbara coast, which recently saw more than 30,000 dead fish wash up at 40 Mile Beach near Karratha (link to ABC news article here).
With the strengthening Leeuwin Current bringing warmer waters down the coast, it is likely that the marine heatwave will reach the West Coast and South Coast regions.
Uncertainties and concerns for our marine ecosystems
Many of you will recall the 2011 marine heatwave event which caused widespread impacts on marine habitats, fish stocks and, consequently, fishing experiences for West Australians.
While some of us may be looking forward to a good metro mackerel season on the back of this news, there are concerns given what happened in 2011.
To recap, effects of the 2011 marine heatwave included:
- Significant reduction in abalone stocks north of Perth, with recovery taking over a decade.
- Sharp declines in Shark Bay’s crabs, scallops and prawns, leading to fishery closures in 2012.
- Extensive loss of macroalgae and kelp habitats in the Mid-West region including Jurien Bay.
- Changes to distribution and recruitment of demersal species like dhufish and pink snapper (for which any impacts on fishing experiences remain unclear).
- Seagrass habitat losses in Shark Bay.
- Reduced herring recruitment, and,
- While we saw an increase in the southern migration of tropical species (such as Spanish mackerel), it disrupted the northern migration of Australian salmon up the West Coast.
More focus and investment on resilience-building needed now
With climate models predicting these events will become more frequent, more must be done to prioritise resilience-building measures to offset some of the impacts and protect the quality of our marine ecosystems and fisheries.
Ahead of the State election, on behalf of the cast of thousands, we’ve reiterated a need for more focus and investment on resilience-building measures, such as:
- Expanding habitat restoration and enhancement efforts such as seagrass and shellfish reseeding and artificial reefs.
- Expanding strategic fish stocking to support recruitment and boost fish abundance.
- Establishing a Fisheries Adjustment Scheme for fisheries impacted by climate change.
- Phasing out gillnets in nearshore and estuarine waters.
We don’t have to be passive onlookers or hysterical doomsayers – what’s needed is cohesive planning and a commitment of real investments and actions to help protect the things that matter to thousands of WA fishers – and the time to act is now.
If you see a fish kill, please report it immediately to DPIRD’s FishWatch hotline on 1800 815 507.
