WFS Admin

I was surprised to see South Australia’s dusky morwong, or strongfish, being called butterfish on social media.

As a former Adelaide fisho, whose father also grew up and fished Adelaide waters, butterfish to us was always the South Australian name for mulloway, not morwong.

Nonetheless, the name has been used for both mulloway and dusky morwong over the years, and a variety of other fish.

Strongfish, or “strongies”, are the ever-present staple of spearfishermen in Adelaide’s seagrass beds.

They taste “strong” as they apparently eat a lot of weed, however people do eat them. How you cook them and how hungry you are will likely determine your opinion of them as a table fish.

Some fishos will tell you they are called strongfish because they are powerful, but they are rarely taken on a line. They are a solid fish and they grow large.

In South Australia, especially in Adelaide and around the Coorong and lower Murray, mulloway were called butterfish because of their rich, smooth flesh – described by some as buttery.

Perhaps the strongie was called butterfish for the opposite reason – you need butter to make them taste good.

Elsewhere in the world this family fish are called butterfish … https://en.wikipedia.org/wiki/Stromateidae

A friend told me years ago that the humble pomfret was a great table fish that flew under the radar, yet another species called butterfish, as are the ever-present (in retail outlets at least) hake.

WFS Admin

The Great Southern Reef Research Partnership (GSRRP) warned in 2023 that a bloom was likely, mainly because of a worsening marine heatwave.

Late 2024 – The Setup

October–December 2024

Sea-surface temperatures in the Great Australian Bight and South Australian gulfs start trending 1–2°C above average due to a combination of El Nino conditions and climate change–driven ocean warming.

Satellite observations pick up weaker-than-normal winter mixing in gulf waters, meaning nutrients and oxygen are not being redistributed effectively.

Scientists begin noting ideal preconditions for a summer marine heatwave, similar to those described in the 2023 warning from the Great Southern Reef Research Partnership (GSRRP).

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Early 2025 – Conditions Intensify

January–March 2025

Marine heatwave thresholds are breached in parts of Spencer Gulf and Gulf St Vincent — water temps stay above the 90th percentile for multiple weeks.

Local marine biologists report that early microalgae density increases.

Commercial fishers notice patchy fish movements, likely due to lower oxygen in warmer waters.

No emergency intervention triggered — conditions monitored but not acted upon, though what could be done is debatable.

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Mid 2025 – Scientists Renew Warnings

May 2025

GSRRP sends a second formal warning to the federal government, highlighting that sea temperatures were now persistently in the danger zone.

Reports nutrient levels consistent with bloom development, partly from agricultural runoff and partly from a natural upwelling.

Warns explicitly that a toxic algal bloom in the gulfs is “highly probable” in the coming months.

Urges rapid-response measures — such as coordinated water sampling, aquaculture monitoring, and contingency plans for closures.

Federal government does not allocate emergency funding at this stage.

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The Bloom Survives Winter

July 2025

Bloom expands rapidly across Spencer Gulf and into Gulf St Vincent.

Fish kills reported along the Eyre Peninsula and Yorke Peninsula.

Mussel and oyster farms suspend harvesting in affected areas due to paralytic shellfish toxin (PST) levels.

Federal government announces $14 million emergency package — most funds aimed at research and industry relief.

Scientists state bloom is well established and cannot be reversed in the short term.

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August 2025

Bloom continues to affect large areas. Fishery closures in place.

Economic impacts estimated in the tens of millions for SA’s seafood industry.

Calls from scientists and industry leaders to establish the national reef monitoring program first requested in 2023.

State and federal agencies collaborating on post-bloom recovery plans, but the bloom may continue as the water warms again into spring and summer.

WFS Admin

To boost morale during the disastrous marine bloom affecting the South Australian coast, the state government has announced it will build oyster reefs at 15 locations in SA’s two gulfs and around Kangaroo Island.

Recfish SA said this was the largest recreational fishing support in South Australian history.

SA Premier Peter Malinauskasis said the oyster reefs would help restore the environment and be a natural defence against algal blooms.

The reefs are in addition to modular unit reefs already announced.

The oyster reefs will cover a total of 15 hectares.

While this is great news, and the state’s existing oyster reef installions have thrived (at least until the recent bloom), fishos wonder whether these reefs will be “scrubbing the ballroom floor with a toothbrush” if the vast algal blooms persist.

Research has noticed a recent change in Southern Ocean current. This may or may not have contributed to a cold water upwelling that supposedly helped get the bloom going, along with unusually warm water, calm weather and a major Murray River flood that dumped coastal nutrients back in 2022/23.

The million dollar questions are: Will bloom conditions persist into the future? Will the oyster reefs and associated fish survive them?

Murray floods and warm water will of course happen more under climate change, and there may be more chance of cold water upwellings.

Interesting times.