Theme E: Interactions between wild and released animals and their ecological and genetic implications
25. OVERLAP OF HOME RANGES OF RESIDENT AND INTRODUCED SOUTHERN ROCK LOBSTER AFTER TRANSLOCATION
Bridget Green, Caleb Gardner and Hugh Pederson
Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Private Bag 49, Tasmania, 7001, Australia
Bridget.Green@utas.edu.au
Translocation and sea-ranching are under scrutiny as methods to augment populations so that harvests can be increased or populations can better adapt to changing environmental conditions. Understanding the ecological effects of any such environmental manipulation is critical to its’ successful application. One potential ecological effect of any type of stock enhancement is the displacement of either resident or the released groups such that finding shelter or foraging habitat is adversely affected. We examined behavioural interactions of resident and translocated Jasus edwardsii rock lobster after an introduction of 1,961 ‘small pale’ phenotypic morphs to an area populated by the resident ‘large red’ phenotypic morph. This translocation was an experimental stock enhancement conducted as part of a larger study to increase the yield and value of the fishery. Most translocated individuals established home range within a couple of days of release (generally < 2) and these ranges were generally less than 1.0ha in size. Home range kernels and foraging ranges overlapped between the two morphs, and there was no evidence of avoidance (Jacob’s cohesion index 0.01, Z=1.06, p=0.28). This case of translocation for stock enhancement between ecotypes had no detectable adverse effect on either the resident or the translocated population, and in this species stock enhancement could become part of an integrated conservation and harvest optimisation strategy.
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