Scientists from the Department of Primary Industries and Regional Development (DPIRD) are showcasing WA fisheries research at an international conference in Fremantle.
Supported by the Western Rock Lobster Council, Australia’s Fisheries Research and Development Corporation and DPIRD, this week’s Lobster and Crab Conference has brought together fisheries scientists, managers, and stakeholders from 18 countries.
Climate change is a key focus for fisheries worldwide and the conference will today feature WA research to measure and manage the impacts of warming environmental conditions and the potential for more frequent marine heatwaves.
DPIRD Principal Research Scientist Nick Caputi will present studies of a marine heatwave off the WA coast in 2011, which found juvenile western rock lobsters were negatively affected. The research also found they were sensitive to the varying strengths of the Leeuwin Current and winter storms.
“There are likely to be ongoing climate-linked changes that will affect the biological parameters of the western rock lobster fishery, both positively and negatively, including factors like the timing of migration, moulting and size at maturity,” Dr Caputi said.
“The research revealed the marine heatwave had a negative effect on the juvenile phase of the lobster stock, especially in the northern part of the fishery, and with climate change we can expect warmer oceans and more frequent heatwave events.”
Another popular crustacean being reported on at the conference this afternoon is the blue swimmer crab, with researchers exploring the crab catch and effort.
DPIRD’s Dr Eva Lai said in the absence of regular quantitative data for the recreational sector, developing a time series of reconstructed catch and effort had been a valuable tool in assessing the recreational catch for blue swimmer crabs.
“Because of reporting requirements, we know the total commercial catch of blue swimmer crabs. However, assessing the recreational catch has been more complex,” Dr Lai said.
“For WA’s Peel-Harvey blue swimmer crab fishery, a time series reconstruction included statistical comparison of catch and effort estimates from varying recreational fishing surveys. This included using two access point (boat-ramp) surveys, three roving (shore-based) surveys and five phone-diary surveys, with additional data coming from camera surveys between 1998/99 and 2020/21.
“Reconstructions of recreational blue swimmer crab fishing had provided a time series to compare against the commercial catch and can be applied to stock assessments.”
The 12th International Conference and Workshop on Lobster (and Crab) Biology will continue through until Friday at the Esplanade Hotel in Fremantle.