Current and Historic Marine Heatwaves

​Current marine heatwave status

There are no current marine heatwaves occurring in Tasmania. This page will be updated during a marine heatwave or if a marine heatwave is forecast.

Actions you can take during a marine heatwave

When there is an active marine heatwave you should:

  • Be cautious when eating or using wild caught seafood - Harmful algal blooms (including paralytic shellfish toxins) and diseases are more common during marine heatwaves, which can increase your risk of getting sick from eating wild caught seafood. Visit the Department of Health's website for advice and current public health alerts.
  • Be vigilant about biosecurity Diseases, like abalone viral gangleoneuritis (AVG) and vibrio, are more common during marine heatwave events. To prevent the spread of disease:
    • Wash down boats, fishing and dive gear when moving between areas.
    • If you catch your own bait, source it from the same area where you fish.
  • Report signs of marine heatwaves -  By reporting marine heatwave signs, you can help NRE Tas respond to and reduce heatwave impacts on the environment, industry and the community. See below for more detail.

Signs of a marine heatwave and where to report them

Signs of a marine heatwave

During a marine heatwave event, you may see:

  • Fish and shellfish (including abalone, rock lobster and scallops) becoming sick or dying (e.g., sluggish or wasting animals, unusual piles of shells, discoloured or poor meat).
  • Changes to seagrass beds, kelp forests and other marine habitats.
  • Unusually large numbers of fish dying (and more rarely, birds, seals, dolphins, or whales). This may be due to increased biotoxins from harmful algae (known as an unusual mortality event).
  • Tropical or warmer water fish being seen in Tasmanian waters.

Where to report signs of a marine heatwave

If you see signs of a marine heatwave, please report them. Your observations are crucial for helping us respond to and reduce the impact of marine heatwaves. 

If you can, take photos of anything you see that may be an impact from a marine heatwave event to include in your report.

​Heatwave sign
​Where to report
Suspected disease emergency
(e.g. large numbers of dead or dying animals)
​Call the 24-hour Emergency Disease Hotline on 1800 675 888
For more information go to Animal Health Laboratory | NRE Tasmania
Sick, dying and dead marine mammals and seabirds​Call the Marine Wildlife Hotline on 0427 942 537. Time is critical during a rescue attempt, or for testing deceased animals to determine the cause.
For more information go to Marine Mammal Incident Response | NRE Tasmania
Mass fish kills
(take photos if you can)
​Call the EPA Incident Response Hotline on 1800 005 171, or email to incidentresponse@epa.tas.gov.au
In order to minimise potential risk to yourself if you see a fish kill do not:
  • Touch the fish or water in the area.
  • Collect fish for bait or other purposes (such as garden fertilisers).
  • Consume any fish that have been caught in the area.
For more information go to Fish and Fish Kills | EPA Tasmania
​Small numbers of sick, dying and dead fish (including shellfish, crustaceans and other marine molluscs)​Call Biosecurity Tas (during office hours) on 03 6165 3777, or complete the online form to Report Signs of a Marine Heatwave.
Do not collect samples for testing unless directed to by Biosecurity Tasmania.
​Observed impacts on the threatened Maugean skate or handfish​Email to ThreatenedSpeciesEnquiries@nre.tas.gov.au and provide as much detail as possible. The recovery teams for Maugean skate or handfish will be notified.
​Warm water species outside their normal range​Contact Redmap or make a report on the Redmap app (download from Google Play or the App Store).
​Other, non-urgent observations​Use the online form to Report Signs of a Marine Heatwave.
Do not use the online form to report marine mammals and seabirds.


Algal blooms may also be more common during marine heatwaves. Most blooms that are visible to the human eye are not dangerous and do not need to be reported. Blooms of Noctiluca (also known as a red tide) maybe highly visible, but are not regarded as harmful to humans and are only slightly toxic to fish. Large blooms are best avoided for recreational swimming because of possible skin irritation. For further information please visit Derwent Estuary Program - Red Tide Algal Blooms.

Historic marine heatwaves

2023-24

A major marine heatwave occurred off eastern Australia in 2023–24. The heatwave was declared from December 2023 to July 2024, with over 197 days with heatwave conditions ranging from moderate to extreme across State waters.

  • Severity of conditions varied across the state, with some areas experiencing extreme conditions (>3.8°C Sea Surface Temperature (SST) anomaly) for between 7 and 51 days consecutively.
  • All areas in the state experienced at least one event categorised as Moderate, with the duration ranging from 5 to 68 days and the SST ranging from 0.7 to 2.2°C.
  • Severe and extreme conditions occurred mostly along the North and North-East coasts.
  • An emergency intervention was taken to temporarily collect a population of Red Handfish (Thymichthys politus) from South Eastern Tasmanian waters to prevent possible extinction of the species.

Impacts of the 2023-24 marine heatwave are still being assessed.

2015-16

A major marine heatwave occurred in south-eastern Australian waters in the summer of 2015–16, including in Tasmania. It lasted for 251 days and reached a peak temperature anomaly of 2.9°C above the normal range. Apparent impacts included:

  • the first outbreak of Pacific Oyster Mortality Syndrome (POMS) in Tasmania

  • regional above-average abalone deaths

  • die-back of bull kelp (Durvillaea spp.)

  • localised bleaching of crayweed (Phyllospora comosa)

  • out-of-range fish observations (Oliver et al., 2018).

Other historic marine heatwave impacts

Other historic impacts to Tasmanian ecosystems that have been associated with marine heatwave events include:

  • 2012 - Deaths in Atlantic salmon (Salmo salar) linked to marine heatwave event (Oliver et al. 2018).
  • 2010 - Mass deaths of Tasmanian ablaone (Haliotis spp.) in March 2010.
  • 2000-01 - Die-back of crayweed kelp beds (Phyllospora comosa).
  • 1988 - Die-back of giant kelp (Macrocystis pyrifera)

References

Oliver, E.C.J., Lago, V., Hobday, A.J., Holbrook, N.J., Ling, S.D., Mundy. C.N., 2018 “Marine heatwaves off eastern Tasmania: Trends, interannual variability, and predictability”, Progress in Oceanography, Volume 161, pp. 116-130, https://doi.org/10.1016/j.pocean.2018.02.007.

Oliver, E., Benthuysen, J., Bindoff, N. et al. 2017 “The unprecedented 2015/16 Tasman Sea marine heatwave”. Nat Commun 8, 16101. https://doi.org/10.1038/ncomms16101


References
Oliver, E.C.J., Lago, V., Hobday, A.J., Holbrook, N.J., Ling, S.D., Mundy. C.N., 2018 “Marine heatwaves off eastern Tasmania: Trends, interannual variability, and predictability”, Progress in Oceanography, Volume 161, pp. 116-130, https://doi.org/10.1016/j.pocean.2018.02.007.
Oliver, E., Benthuysen, J., Bindoff, N. et al. 2017 “The unprecedented 2015/16 Tasman Sea marine heatwave”. Nat Commun 8, 16101. https://doi.org/10.1038/ncomms16101
Algal blooms may also be more common during marine heatwaves. Most blooms that are visible to the human eye are not dangerous and do not need to be reported. Blooms of Noctiluca (also known as a red tide) maybe highly visible, but are not regarded as harmful to humans and are only slightly toxic to fish. Large blooms are best avoided for recreational swimming because of possible skin irritation. For further information please visit Derwent Estuary Program - Red Tide Algal Blooms.

    Hotline

    Fishwatch Report illegal fishing

    0427 655 557

    What to report? arrow button

    Contact us

    Recreational Fishing

    Level 3, 134 Macquarie St

    Hobart TAS 7000

    Phone: (03) 6165 3233, 1300 720 647

    Email: fishing.enquiries@nre.tas.gov.au

    Commercial Fisheries

    Level 3, 134 Macquarie St

    GPO Box 44

    Phone: (03) 6165 3000, 1300 368 550

    Email: commercial.fisheries@nre.tas.gov.au

    Commercial Fisheries Licensing

    Level 1, 134 Macquarie St

    GPO Box 44

    Phone: (03) 6165 3000, 1300 368 550

    Email: fisheries.licensing@nre.tas.gov.au