Long-term movement patterns of continental shelf and inner gulf snapper (Pagrus auratus, Sparidae) from tagging in the Shark Bay region of Western Australia

2003 ◽  
Vol 54 (8) ◽  
pp. 913 ◽  
Author(s):  
M. Moran ◽  
C. Burton ◽  
J. Jenke

Snapper is an important commercial and recreational target species in the Shark Bay region of Western Australia. The present study aimed to define the range of movements of snapper by tagging in the two inner gulfs of Shark Bay and on oceanic fishing grounds adjacent to the Bay. Recaptures by fishers fell to low levels within 4 years after tagging, but small numbers of recaptures were still being made up to 15 years after release. There was no mixing of snapper populations between the two inner gulfs nor was there any movement between the ocean and the inner bay. This supports genetic and other evidence for the existence of several separate stocks in the region. Snapper of the ocean stock were mostly recaptured within 20 km of their release point, although a few fish moved long distances of up to 370 km southwards along the continental shelf. The tagged snapper tended to become more dispersed along the shelf with increasing years at liberty. Yet, an empirical model indicated that of the snapper recruiting to the main oceanic fishing grounds near Koks Island, which have a mean life expectancy in the fishery of 1.5 years, 76% would remain within 93 km (50 nautical miles), even after 6 years. The distinct stocks and their movement characteristics are significant for snapper fishery management in the Shark Bay region.

2014 ◽  
Vol 41 (2) ◽  
pp. 117 ◽  
Author(s):  
Shannon J. Dundas ◽  
Peter J. Adams ◽  
Patricia A. Fleming

Context In Western Australia, baits containing 1080 poison are widely used to control the red fox (Vulpes vulpes) for fauna conservation. Despite long-term (15–17 years) baiting programs, bait uptake by target and non-target species is largely unknown, but affects baiting efficacy. Aims We examined bait uptake of 1080-poisoned fox baits laid according to current practice at seven riparian sites in the northern jarrah forest (of south-west Western Australia). There, intensive baiting regimes have been implemented for the protection of quokka (Setonix brachyurus) populations. Methods Over 9 months, 299 Probait® baits were monitored regularly to determine their persistence, and, at 142 of these, Reconyx HC500 remote cameras were used to identify the species taking baits. To compare bait uptake with species presence at these sites, we calculated an activity index for each species from the number of passes of animals in front of the cameras. Key results The species taking baits was identified for 100 of the baits monitored with cameras, and, because of multiple species taking baits, 130 bait take incidents were recorded in total. The fate of 40 of the baits was not discernible and two baits were not removed. In all, 99% of baits monitored by cameras were taken by non-target species and quokkas took 48% of them. The majority of baits (62% of the total 299 monitored) were taken before or on the first night of deployment, and 95% of baits had been taken within 7 days. With the exception of feral pigs, which took more baits than predicted from their activity index at these sites, baits were taken in proportion to the activity index of species. Foxes were present at four of the seven sites, but only one fox was observed taking a bait. Conclusions The high level of uptake of baits by non-target animals reflects their diversity and abundance at these sites, but also significantly reduces the availability of baits to control foxes. Implications Strategies to reduce non-target bait uptake and increase bait availability for foxes are required.


2007 ◽  
Vol 151 (4) ◽  
pp. 1455-1461 ◽  
Author(s):  
Michael R. Heithaus ◽  
Aaron J. Wirsing ◽  
Lawrence M. Dill ◽  
Linda I. Heithaus
Keyword(s):  

1999 ◽  
Vol 50 (1) ◽  
pp. 27 ◽  
Author(s):  
M. Moran ◽  
C. Burton ◽  
N. Caputi

Sexual dimorphism is demonstrated in pink snapper, Pagrus auratus (Sparidae), from the Shark Bay region of Western Australia, by canonical variate analysis of 13 morphometric measurements of the head. Snapper of both sexes develop a prominent hump on the forehead as they grow to large size, but the males do so to a greater extent than the females. Males also develop a bulge on the snout which was not found in females. Snapper with humps are less well accepted in an export market and this may result in high-grading problems in the quota-managed commercial fishery. Morphometric differences between localities were also found, with three regions previously recognized as containing separate genetic stocks being clearly distinct. Snapper from four areas within one of these stocks, the widespread ocean stock, were compared and found to show lesser differences. These four population samples fell into two groups, interpreted as a resident inshore group and an offshore group which migrates inshore for spawning. The local differences indicate incomplete mixing which has implications for fisheries management and stock assessment.


2013 ◽  
Vol 35 (1) ◽  
pp. 128 ◽  
Author(s):  
M. J. Page ◽  
J. Kuiper ◽  
A. P. Kabat ◽  
S. Legge

Elliott traps are widely used in Australia to capture small terrestrial mammals. However, in some situations non-target species disturb the traps, resulting in fewer traps being available for the target species. This situation occurred on Faure Island Wildlife Sanctuary (Western Australia) where boodies (burrowing bettongs) were disturbing the Elliott traps deployed to monitor populations of shark bay mice and western barred bandicoots. This note presents the method used to alleviate this problem on Faure Island but would be more widely applicable in other situations where Elliott traps are disturbed by animals other than the target species.


2012 ◽  
Vol 63 (11) ◽  
pp. 1129 ◽  
Author(s):  
B. S. Wise ◽  
C. F. Telfer ◽  
E. K. M. Lai ◽  
N. G. Hall ◽  
G. Jackson

Effective management of a recreational fishery must include long-term monitoring programs that allow determination of trends in temporal and spatial variability of catch and effort data. Such monitoring becomes of inherently greater importance when managing a recreational fishery in a World Heritage Area, such as Shark Bay, Western Australia. Between 1998 and 2010, 11 12-month bus-route surveys of boat-based recreational fishing were undertaken at three key boat ramps in Shark Bay. These surveys demonstrated that, in response to the progressive implementation of new management measures, the estimated annual recreational fishing-boat effort decreased by 46%. As a consequence, the estimated annual retained and released catches of the key species, pink snapper (Pagrus auratus), declined and the proportions of the catches of this species that were released each year increased. Annual catches of other species also declined, however, the composition of species retained and released each year varied. The study demonstrated that monitoring of the recreational fishery within Shark Bay provided both immediate and longer-term data on the responses by recreational fishers to changes in management. This produced the information necessary to assess the effectiveness of management measures that were introduced and to modify these as required.


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