Fishing for rock lobster data in the Torres Strait

As sea levels continue to rise around the 18 islands and two peninsulas of the Torres Strait, researchers are delving into the impacts of climate change on the region’s fisheries – including the tropical rock lobster industry.

The tropical rock lobster, traditionally known as “kaiar”, is the Torres Strait’s most valuable fishing industry, earning just over $16 million in 2021-22 with most of the shellfish going to China and the United States.

Following 35 years of surveying rock lobsters in the Torres Strait, the CSIRO has now started to look at the current and future risks of climate change to help manage the rock lobster industry, as well as the sea cucumber (aber) and finfish industries.

“Although the lobster surveys show the fishery is naturally highly variable, climate change is causing this variability to become even more extreme in some years and there are increasing impacts on lobsters and habitat,” CSIRO senior principal research scientist and project lead of the Torres Strait tropical rock lobster survey, Dr Eva Plaganyi says.

“The variability means the numbers of lobsters available to be caught sustainably by the fishery can double or halve from one year to the next. The survey data are rapidly processed and analysed to help inform the setting of a Total Allowable Catch each year.”

Plaganyi says by tracking the health of the ecosystem through the CSIRO adaptation and mitigation strategies project, scientists can better understand what will happen next.

Eva plaganyi. Jpeg
CSIRO senior principal research scientist and project lead of the Torres Strait tropical rock lobster survey, Dr Eva Plaganyi, holding a live tropical rock lobster/Kaiar. Image: CSIRO

The Torres Strait Regional Authority says sea levels in the region are rising by 6-8mm per year, with the water becoming warmer and more acidic, and this year’s El Nino event will throw another challenge into the mix. The CSIRO has noted research shows past El Nino events have led to “poor subsequent recruitment and catches of lobsters in Torres Strait”.

An assessment of the Torres Strait tropical rock lobster fishery released by the Federal Department of Climate Change, Energy, the Environment and Water in October found because the rock lobsters are largely collected by hand.

The chaotic life of the lobster

The CSIRO’s annual survey shows fluctuations in the catch of between 132 tonnes and 917 tonnes per year over the past 40 years.

CSIRO senior research scientist and project lead of the new project, Dr Laura Blamey, says climate change is posing an increasing threat to fisheries that played an important role in the lives of Torres Strait Islanders.

“Rising sea levels, warmer atmospheric and ocean temperatures, more acidic waters, changes in ocean circulation, and more intense rainfall patterns are expected to have both direct and indirect impacts on the abundance, distribution, growth, reproductive capacity, and phenology of key species in these fisheries,” Blamey says.

The study will build a three-dimensional ocean model to generate data based on climate change scenarios. These scenarios will feed into a Model of Intermediate Complexity for Ecosystem assessment (MICE) to look at impact on fisheries and species.

The Greenlight Project is a year-long look at how regional Australia is preparing for and adapting to climate change.

The Ultramarine project – focussing on research and innovation in our marine environments – is supported by Minderoo Foundation.

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