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Seminar 4 July 2013

SARDI SEMINAR SERIES 2013

Date:        Thursday 4 July
Time:        2noon
Duration:   ~ 30 mins
Location:   Lecture Theatre, SARDI Aquatic Sciences Centre, 2 Hamra Ave, West Beach
Catering:   lunch to follow
Speaker:    Craig Mundy, Institute for Marine and Antarctic Studies

 

“Genetic population structure in Greenlip Abalone from SE Australia: implications for management of an important commercial fishery”

Abstract:

Fine-scale population structure is common in many inshore marine species, particularly sedentary invertebrates with limited larval dispersal whose populations (or stocks) tend to be characterised by a complex spatial structure evident at fine spatial scales. Assessment and management of such spatially complex stocks is challenging, which has resulted in assessment and management processes occurring at spatial scales which can vary considerably from the spatial complexity of the stocks. Despite commercial catches of Greenlip abalone exceeding 700t/year across Southern Australia, relatively little work has been done to understand the spatial scale of stock structure or level of connectivity in this species, nor how it relates to current management approaches. We used 15 microsatellite DNA markers to assess genetic structure of 2500 greenlip abalone collected from the Great Australian Bight to northern Tasmania. We found large, and highly significant genetic differences among large biogeographic regions (Great Australian Bight, Spencer Gulf, Bonnie Upwelling, Port Phillip Bay, NE Tasmania) as well as significant spatial structure on the scale of tens of kilometres within regions. Unlike the closely related blacklip abalone which shows very small scale patterns of differentiation (hundreds of metres), our data indicates that greenlip abalone populations are panmictic across as much as 3-5km.  Furthermore, there is little evidence that areas that have been traditionally considered as important sources of larvae by fishers contribute disproportionately to recruitment.  These findings will have important implications for current management and will inform the development of representative spatial management systems for the fishery.

All welcome