Colour variation in the southern rock lobsterJasus edwardsiiand its economic impact on the commercial industry

Abstract

Southern rock lobster Jasus edwardsii varies in shell coloration throughout southern Australia. Predominantly exported as a live product to Asian markets, price is influenced by colour with prices higher for dark red than paler coloured lobsters, which are discounted. This paper explores spatial and depth variation in shell colour for the Tasmanian, South Australian and Victorian fisheries using catch sampling data. The proportion of red lobsters decreased with depth and was prevalent at depths less than 30 m, whereas paler coloured lobsters dominated the deeper depth ranges. The depth of transition where 50% of lobsters were classified as red showed a weak trend of increase with latitude from southern Tasmania to northern South Australia. Under quota management, lobster colour was a significant driver of fleet dynamics as fishers target areas of high price per unit. Consequently, catches of pale lobsters from greater depths remain low despite the high catch rates in these areas. The colour price differential varies seasonally (higher in summer) so fishers increase supply of pale lobsters during winter. Discounting on colour equates to AUS$6.67 million/year for the Tasmanian Fishery alone, which indicates value from management or marketina research to reduce discountina.

Overlap of Home Ranges of Resident and Introduced Southern Rock Lobster after Translocation

“…The translocation experiment described here was part of a large study that increased the yield and value from the translocated SP morphs (Chandrapavan et al, 2009a(Chandrapavan et al, , 2010(Chandrapavan et al, , 2011b. The results of the present study on cohabitation show that these benefits came without any apparent cost in terms of short-term displacement or behavioral impacts on resident LR morphs' sustainability.…”

“…As red is inherently intimidating in freshwater fishes and terrestrial species (Barlow, 1983;Vercken and Clobert, 2008), and size differences can increase agonistic behavior in captive lobsters and catchability in wild J. edwardsii lobsters (Frusher et al, 2003;Thomas et al, 2003), there was concern that the SP lobsters might be at a disadvantage when introduced into the territory of LR lobsters due to color, size, and prior residence dominance and disorientation upon release. A larger translocation experiment using lobsters from the same source site but translocated to other sites on the Tasmanian coast was effective at changing the color, growth rate, body shape, and size, increasing the value and nutrition of the seafood product (Chandrapavan et al, 2009a(Chandrapavan et al, ,b, 2010(Chandrapavan et al, , 2011aGreen et al, 2010). For an assisted migration and restocking to be successful, transplants must survive and prosper in their new environment, establishing residences and home ranges (HRs), thereby increasing productivity (Hilborn, 1998;Bell et al, 2006Bell et al, , 2008.…”

“…The southern rock lobster Jasus edwardsii has two apparent phenotypic morphs-a small slow-growing red and white speckled morph ("small pale" [SP] morph) with longer legs, which resides in deep water, and a larger faster-growing, red morph ("large red" [LR] morph) with shorter legs, which resides in shallow water (Chandrapavan et al, 2009a)-but are of one genetic stock (Ovenden et al, 1992). Demographic traits of these morphs differ also; the SP phenotypic morph matures at a smaller size (65-mm carapace length [CL]), is slower growing, and tends to have low exploitation rate and high densities (Punt et al, 1997).…”

Integrating recapture-conditioned movement estimation into spatial stock assessment: A South Australian lobster fishery application

“…Analyses of the spatial dynamics of the commercial lobster fishing fleet under total allowable commercial catch (TACC) regulations suggests that effort has shifted to inshore grounds in recent seasons (Linnane and Crosthwaite, 2009). This was driven by market demands for small (<1 kg) "red" individuals that are primarily found at shallower depths (Chandrapavan et al, 2009). As a result, fishery-dependent data indicate that ∼80% of the current TACC in South Australia is now taken in depths of <60 m (Linnane et al, 2007).…”

Marine Stock Enhancement, Restocking, and Sea Ranching in Australia: Future Directions and a Synthesis of Two Decades of Research and Development

“…Second, the translocation of larger lobsters was examined as an approach to improve fishery production and yield. Some lobsters in shallow water (<30 m deep) are darker red and fetch a higher price than lobsters in deeper water (<30 m; Chandrapavan et al, 2009). Furthermore, the growth rate of lobsters decreases with increasing latitude and increasing depth (Chandrapavan et al, 2010).…”