Investigation of Genetic Structure between Deep and Shallow Populations of the Southern Rock Lobster, Jasus edwardsii in Tasmania, Australia

Abstract

The southern rock lobster, Jasus edwardsii, shows clear phenotypic differences between shallow water (red coloured) and deeper water (pale coloured) individuals. Translocations of individuals from deeper water to shallower waters are currently being trialled as a management strategy to facilitate a phenotypic change from lower value pale colouration, common in deeper waters, to the higher value red colouration found in shallow waters. Although panmixia across the J. edwardsii range has been long assumed, it is critical to assess the genetic variability of the species to ensure that the level of population connectivity is appropriately understood and translocations do not have unintended consequences. Eight microsatellite loci were used to investigate genetic differentiation between six sites (three shallow, three deep) across southern Tasmania, Australia, and one from New Zealand. Based on analyses the assumption of panmixia was rejected, revealing small levels of genetic differentiation across southern Tasmania, significant levels of differentiation between Tasmania and New Zealand, and high levels of asymmetric gene flow in an easterly direction from Tasmania into New Zealand. These results suggest that translocation among Tasmanian populations are not likely to be problematic, however, a re-consideration of panmictic stock structure for this species is necessary.

Temporal genetic patterns of diversity and structure evidence chaotic genetic patchiness in a spiny lobster

“…The significant interaction between site and puerulus year (AMOVA neutral SNPs, Table ) found in the present study and the significantly different pairwise F ST values found herein further support the existence of chaotic genetic patchiness. In the case of J. edwardsii , while examination of the adult populations generally concludes panmixia within Australia (Morgan et al., ; Thomas & Bell, ; Villacorta‐Rath et al., ), our analysis including cohorts of pueruli over time and space blurs this conclusion. Recently settled individuals (stage 1–2 pueruli) analysed in the present study exhibited a nonsignificant global level of genetic differentiation ( F ST = −0.0042), suggesting that there is gene flow between South Australia and Tasmania.…”

“…It occupies a wide geographic range, approximately between 110–180°E and 30–50°S, and subpopulations are exposed to different temperature regimes along this latitudinal gradient (Hinojosa et al., ). Studies assessing population structure of J. edwardsii have distinguished large‐scale neutral and adaptive differences between populations in Australia and New Zealand (Morgan, Green, Murphy, & Strugnell, ; Thomas & Bell, ; Villacorta‐Rath et al., ). Although the sampling design of those studies did not allow structure in adult populations to be distinguished at a regional level, larval transport simulations suggest that there is genetic exchange between populations in Australia (Bruce, Griffin, & Bradford, ).…”

Bio-economics of commercial scale translocation of southern rock lobster

“…Key results from field trials were that slow-growing lobsters that were moved to inshore areas: (a) changed colour within a year (Chandrapavan et al, 2009a); (b) increased their growth rates to that of the new site (Chandrapavan et al, 2010); (c) survived in their new location ); (d) increased egg production ; (e) improved their condition and body chemistry (Chandrapavan et al, 2009b(Chandrapavan et al, , 2011a); (f) changed body morphology to a higher valued shape (Chandrapavan et al, 2011b); and (g) stayed at the release site (Green et al, 2013b). This research also demonstrated that these changes were phenotypic, not genetic (Morgan et al, 2013).…”

“…These differences are phenotypic rather than genetic (Morgan et al, 2013), with lobsters from deep-water regions in the south west of Tasmania tending to grow slowly in high density populations, while lobsters from shallow-water or northern areas grow far more rapidly (Gardner et al, 2006;Punt and Kennedy, 1997). Translocation involves capturing slow growing lobsters that are below the minimum legal size and moving these lobsters to regions where their growth improves and they develop more valuable market traits (Chandrapavan et al, 2010(Chandrapavan et al, , 2011a.…”

“…Translocation involves capturing slow growing lobsters that are below the minimum legal size and moving these lobsters to regions where their growth improves and they develop more valuable market traits (Chandrapavan et al, 2010(Chandrapavan et al, , 2011a. The Government of Tasmania approved translocation trials in 2004 after assessing the risk of disease transfer and genetic effects to be negligible, because translocations are over much smaller distances than occurs with larval dispersal, and are comparable to distances over which adults occasionally move (Gardner et al, 2003;Morgan et al, 2013).…”