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Research helps manage lucrative rock lobster industry

Wednesday 1 February 2012, 2:18PM

By Victoria University

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Victoria University research will help support the management of the New Zealand rock lobster industry, worth $220 million each year.

Commonly called crayfish, the red rock lobster (Jasus edwardsii) is New Zealand’s most valuable inshore fishery export so there is considerable interest and investment in sustainably harvesting the species.

Senior Lecturer Dr James Bell and his Master’s student Luke Thomas from the School of Biological Sciences are using DNA technology to increase our understanding of the sources of lobster larvae and movement of larvae between red rock lobster populations in New Zealand and Australia.

Biologically, the rock lobster is a very unusual species in that after fertilised eggs are released from females the larval rock lobsters spend up to 24 months drifting around in the oceans, before finding their way back to rocky habitats. During this time they pass through 11 different larval stages and can potentially travel thousands of kilometres.

Dr Bell says understanding the source of the next generation of any commercial species is of critical importance for its sustainable management.

"The rock lobster presents an interesting challenge with respect to identifying the sources of larvae to harvested populations and larval movement between different locations as it has one of the longest lived larvae of all marine creatures, spending up to two years floating in the oceans before settling.

"This means it is impossible to directly track larval movements so we need to use other tools."

Master’s student Luke Thomas has been developing a series of so-called microsatellite DNA markers to assess variation in the DNA of rock lobsters and therefore larval exchange patterns.

So far the team has identified genetically distinct and isolated rock lobster populations in the lower South Island, along with evidence that some New Zealand rock lobster populations may be receiving around 10 percent of their larvae from Australia.

"The level of reliance of many rock populations on larvae produced a long distance away needs to be considered further in rock lobster management, as this will help to better understand changes in rock lobster stocks between years," says Dr Bell.

"Especially important is the level of dependence of New Zealand rock lobster populations on larvae from Australia, as any declines in overseas rock lobster populations may possibly have knock on effects for populations here."

Dr Bell and his team are working with the New Zealand Rock Lobster Industry Council (NZRLIC), and have funding from the industry body, the Victoria University Research Fund and economic development agency Grow Wellington.

The research is part of Dr Bell’s ongoing international research programme, in collaboration with other researchers in the School of Biological Sciences, into population connectivity, marine conservation and management.