Project number: 2009-020
Project Status:
Completed
Budget expenditure: $163,409.17
Principal Investigator: Jason Kennington
Organisation: University of Western Australia (UWA)
Project start/end date: 24 May 2009 - 29 Jun 2011
Contact:
FRDC

Need

Preliminary investigations suggested that the western rock lobster breeding stock comprised of a single, demographically united and genetically homogeneous population. However, this has yet to be rigorously tested with a highly sensitive genetic technique such as microsatellite DNA markers.

Evidence of spatial genetic structure would have significant implications for stock management. Temporally stable patterns (i.e. the same spatial genetic patterns repeated across different generations) would indicate restricted mixing of adults and larvae, challenging the idea of a single population and suggesting that regional regulation would be more appropriate. Similarly, temporally unstable or ephemeral population structure, which has been found previously with allozymes (and is the more likely scenario), also has important implications. While ephemeral patterns suggest extensive mixing of the larvae, it raises the possibility of genetic tracking of larvae from different sub-populations. These data will greatly improve our understanding of recruitment dynamics in western rock lobsters and help with future management. For example, it may be that some regions contribute disproportionally more recruits than others, in which case measures could be put in place to ensure their protection.

Lastly, relatively little is known about the genetic health and evolutionary potential of the fishery. Small effective population sizes and the associated declines in genetic diversity, such as those recently seen in exploited fish populations (e.g. New Zealand snapper), provide early warning signals of a fishery vulnerable to reduced productivity and loss of an ability to adapt to environmental changes. The genetic data collected in this project will be used to estimate the effective population size of western rock lobsters and test for genetic bottlenecks. This will not only provide important information on the current situation, but it will also provide vital base line data for assessing the future impacts of climate change and fishing on genetic diversity and adaptation.

Objectives

1. Develop additional new microsatellite markers for western rock lobster.
2. Test whether the adult population of western rock lobster is genetically homogeneous throughout its range.
3. Test whether the spatial genetic structure in the next generation of recruits (pueruli) matches the spatial genetic structure found in adults. (If so, this suggests spatial structure is due to limited dispersal or local adaptation).
4. Estimate effective population size of the western rock lobster and test for severe bottlenecks in population size.

Final report

ISBN: 978-1-74052-257-1
Author: Jason Kennington

Related research

Environment
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PROJECT NUMBER • 2019-099
PROJECT STATUS:
CURRENT

Climate driven shifts in benthic habitat composition as a potential demographic bottleneck for Western Rocklobster: understanding the role of recruitment habitats to better predict the under-size lobster population for fishery sustainability

1. The overall objective is to evaluate the implications of habitat change for the western rock lobster fishery, by determining the relative importance of habitat for the survivorship and growth of critical western rock lobster life stages, to inform the interpretation of existing settlement and...
ORGANISATION:
University of Western Australia (UWA)