Fisheries support the lifestyles and livelihoods families and communities across the Torres Strait. However, climate change is having a noticeable effect on the region and its marine ecosystems.
Rising sea levels, warmer atmospheric and ocean temperatures, more acidic waters, changes in ocean circulation, and more intense rainfall patterns are expected to impact the Torres Strait into the future.
In turn, this could affect the abundance, distribution, growth and reproductive capacity of local species.
Our researchers attended a community event on Waiben (Thursday Island) in November 2023. There, together with the Torres Strait Regional Authority (TSRA), they launched a new research project that will provide vital information into the impacts of climate change on key fisheries in local waters.
The project will use modelling to estimate climate change impacts on species such as tropical rock lobster (Kaiar), sea cucumber (Aber) and finfish.
Dr Laura Blamey is our project lead. She said the project is an important step in protecting the future of the fisheries. It is also critical to their ongoing connection with country.
"Things are changing. Waters are warming and we’re likely to see changes in ocean chemistry, leading to more acidic waters," Laura said.
"We can also expect to see changes in the big regional climate drivers like La Niña and El Niño, with increased frequency or intensity of these events, which has the potential to change currents. These changes are expected to impact important habitats and species."
As part of the project, our researchers will collect oceanographic data to inform a 3-dimensional ocean model for the region. They will also be able to generate additional oceanographic data, based on different climate change scenarios.
The modelled data will feed into an integrated ecological model. Known as MICE (Model of Intermediate Complexity for Ecosystem assessment), the model is designed to estimate climate change impacts on selected fisheries and species.
The model results from the Torres Strait MICE will be presented to stakeholders, including community and industry representatives, for discussion. Following this, adaptation strategies will be co-developed in workshops.
TSRA Chairperson Napau Pedro Stephen AM said the project would provide much-needed information to help develop effective climate adaptation responses in the Torres Strait.
"The Torres Strait is a seafaring nation. Beyond income and employment, the sea is part of our identity and who we are," Mr Stephen said.
"We know climate change poses a significant threat to some of our key fisheries, which is why with the support of the TSRA board we have committed to fully funding this initiative.
"Our investment will help local communities access the best science and data to use alongside local knowledge and lived experiences."
Safeguarding the future of tropical rock lobster
The new modelling project will use data that CSIRO has collected over the past 35 years as part of the tropical rock lobster population surveys. The lobster fishery is the most economically important one in the Torres Strait.
Local lobster fisher Harry Nona said he’s concerned about the impacts of climate change.
"I've seen a lot of erosion... we used to travel out to nice beaches, it's not there anymore, it's just rocks now. A lot of the sand has gone away now. Turtles are finding it hard to lay eggs and you don't see many turtles laying eggs," he said.
"And the tides are higher than what it was before. Not much calm weather anymore. The weather's always rough."
Over the past four decades, the total catch of tropical rock lobster has fluctuated between 132 tonnes and 917 tonnes per year for the sector in the Torres Strait.
According to the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) Fishery Status Reports 2023, the total catch for the 2021–22 fishing season was 290.3 tonnes.
Real gross value of production of tropical rock lobster in the Torres Strait has varied in recent years due to COVID, fuel prices and market challenges. It reached $16.03 million for the 2021-22 fishing season, with China and United States making up the primary markets.
Tracking ocean currents
Dr Éva Plagányi is our Torres Strait tropical rock lobster survey project lead. She explained the survey data helps researchers understand how ocean currents are changing over time.
"We count the numbers of lobsters that are recruiting into Torres Strait every year, and we’re able to then look in combination with some of our physical oceanographic data at what the currents were like, and whether that explains how many lobsters we have,” she said.
"When we had that very strong El Niño in 2015/16, it looked like the Coral Sea gyre might have flipped around. The gyre is a big circular current that usually carries the larvae around the Coral Sea and back to settle in Torres Strait. When it switched, some larvae may have got lost towards the east. That might be why fewer large lobsters were available to be caught three years later.
"So, that’s the sort of clue that helps advance our research. As we get more data for more years, we can start seeing how these currents are changing. It helps us better prepare for what might happen to valuable fisheries down the line."
The survey data helps to inform the setting of a total allowable catch in the Torres Strait each year.
The new project ‘Modelling climate change impacts on key fisheries in the Torres Strait to co-develop adaptation and mitigation strategies' is funded by the Torres Strait Regional Authority (TSRA) and CSIRO.