Aj Morton
University of Tasmania
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Publication
Featured researches published by Aj Morton.
Marine and Freshwater Research | 2007
Jm Lyle; Natalie A. Moltschaniwskyj; Aj Morton; Ian Brown; D. G. Mayer
This study examined post-release survival in sand flathead (Platycephalus bassensis) and whether there were survival benefits from the use of circle hooks over conventional hook patterns. Anatomical hooking location was the major factor contributing to mortality, with an almost 100% survival rate for fish hooked in the lip, mouth or eye (shallow-hooked) compared with around 64% for fish hooked in the throat or gut (deep-hooked). Mortality in deep-hooked fish was generally associated with injuries to vital organs (gills, heart, liver) and survival was significantly lower if bleeding was associated with injury (54% compared with 85% for non-bleeders). Circle hooks resulted in significantly lower deep-hooking rates (1%) compared with conventional hook types (4-9%) and, based on catch rates, were at least as effective as conventional hook patterns. Estimated survival rates for line-caught sand flathead were high, over 99% for circle hooks and between 94 and 97% for conventional hooks. These findings support the efficacy of management strategies based on size and bag limits and the practice of catch-and-release fishing for sand flathead, as well as a potential conservation benefit from the use of circle hooks.
New Zealand Journal of Marine and Freshwater Research | 2005
Jm Lyle; Aj Morton; Jane Forward
Abstract Southern rock lobster (Jasus edwardsii) support significant commercial and recreational fisheries in Tasmania, Australia. Since the mid 1990s the number of persons holding recreational lobster licences increased by over 80%, with c. 15 500 persons licensed in 2002/03. Assessment of the recreational fishery has been undertaken periodically since 1996 using a telephone‐diary survey method. The fishery was concentrated off the south‐east and east coasts of Tasmania and characterised by strong seasonality in catch and effort, which peaked markedly early in the fishing year (November‐January). Although pots were the most popular fishing method, daily catch rates by divers were more than double those for pots. Divers selectively harvested larger lobsters than those taken by pots and more frequently attained the daily bag limit of 5 lobsters. The estimated recreational harvest increased significantly since 1996/97 and in 2002/03 effectively reached a management trigger level of 10% of the total allowable commercial catch, flagging a review of recreational management arrangements.
Journal of Experimental Marine Biology and Ecology | 2004
Graham J. Edgar; Ns Barrett; Aj Morton
Journal of Experimental Marine Biology and Ecology | 2004
Graham J. Edgar; Ns Barrett; Aj Morton; Cath R. Samson
Environmental Biology of Fishes | 2004
Graham J. Edgar; Ns Barrett; Aj Morton
Archive | 2004
Jm Lyle; Aj Morton
Archive | 2003
Ns Barrett; Graham J. Edgar; Aj Morton; Cd Buxton
Archive | 2003
Aj Morton; Jm Lyle
Archive | 2002
Ns Barrett; Graham J. Edgar; Aj Morton
Archive | 2002
Jm Lyle; J Forward; Aj Morton