1,723,559 research outputs found
Spanner Crab Fishery Scoping Study
Get PDFThe Queensland Ecological Risk Assessment Guideline (the Guideline) was released in March 2018 as part of the Queensland Sustainable Fisheries Strategy 2017–2027. This Guideline provides an overview of strategy being employed to develop Ecological Risk Assessments (ERAs) for Queensland’s fisheries. The Guideline describes a four-stage framework consisting of a Scoping Study; a Level 1, whole of fishery qualitative assessment; a Level 2, species-specific semi-quantitative or low-data quantitative assessment and; a Level 3 quantitative assessment (if applicable).
The Scoping Study establishes a baseline of information on the key characteristics of the Spanner Crab Fishery. It includes information on the broader management regime, key species, gear configurations and catch and effort trends. Information contained in the Spanner Crab Fishery scoping study will inform subsequent assessments including the whole of fishery (Level 1) ERA and, if applicable, a species-specific (Level 2) ERA
Reinventing the role of the professional services boundary spanner: An exploratory study
No full textThis article explores attitudes towards the professional services boundary spanner in the light of anecdotal evidence challenging the view that the boundary spanner is pivotal to the client-firm relationship. Data were collected using case studies and one-toone interviews. The findings suggest that clients prefer to bypass the traditional boundary spanner so as to liaise directly with agency creatives or account directors, whom they regard as the knowledge holders. However, the boundary spanner fulfils a necessary administrative role and holds valuable tacit knowledge. To prevent dissatisfaction and constant boundary spanner turnover, agencies need to increase boundary spanner autonomy and credibility. © Taylor & Francis Group, LLC
Fisheries long term monitoring program : summary of spanner crab (Ranina ranina) survey results: 2000–2005
No full textThe Department of Primary Industries and Fisheries manages the harvest of Queensland’s fish, mollusc and crustacean species and the habitats they live in. Inherent in this responsibility is a commitment to monitoring the condition and trends in fish populations and their associated habitats. This information is used to assess the effectiveness of fisheries management strategies and contributes to ensuring that the fisheries remain ecologically sustainable. The spanner crab, Ranina ranina, inhabits sandy bottoms on the continental shelf off Australia’s east coast, from southern New South Wales, north to the southern Great Barrier Reef. The annual commercial harvest of spanner crabs in Queensland increased rapidly from 1988 to 1994 with fishing effort and catch rates increasing as the fishery expanded into previously unexploited areas. Since 1999, the fishery has been subject to a Total Allowable Commercial Catch (TACC) in Management Area A, divided between the licensed operators by way of Individual Transferable Quota units (ITQ). The current TACC of 1727 tonnes has been in effect since June 2002.
The present TACC setting decision rules are based on performance criteria derived from commercial catch rates. However, there is concern about the reliability of fishery dependent catch rates as indicators of stock abundance, partly because the stock is not uniformly distributed, resulting in fishers targeting aggregations of crabs. In response to these management concerns and the high value of the fishery (approximately $10 m), spanner crabs were included in the Department’s Long Term Monitoring Program (LTMP).
The objectives of the spanner crab monitoring component of this program are to obtain fishery independent catch per unit effort (CPUE) data, record length frequency and sexratio data, identify interactions with species of conservation interest (SOCI), and monitor bycatch composition.
The sampling design includes five assessment regions (Regions 2 to 6) comprising of the Queensland Commercial Fishery (Managed Area A), which is subject to the TACC. For the 2005 survey an extra region (Region 7) was added in New South Wales. Fifteen sets per subgrids were conducted, with each set consisting of ten standard commercial spanner crab dillies connected by a ‘trot-line’ (or single string). Five subgrids were sampled in Regions 2 to 6, and four subgrids in Region 7. This report presents survey results from five years, 2000 to 2003 and 2005.
A total of 19 290 individual dilly lifts have been undertaken by the LTMP fishery independent spanner crab survey. In the Queensland regions observations of fishery bycatch during 2002, 2003 and 2005 show very low catch rates. Most of the bycatch species captured by spanner crab fishing gear are alive, and expected survival rates after release would be extremely high. To date there is not a single record of physical interaction between sampling gear and marine protected species.
Differences in mean carapace lengths were observed between male and female crabs over all regions. Overall, 68.1% of the 23 842 males and 13.0% of the 4193 females captured over the five year survey period were larger than the minimum legal carapace length of 100 mm. Carapace lengths also varied greatly between all regions sampled (Regions 2 to 7); male crabs were smaller in Region 5 compared to other regions and female crabs were largest in Regions 6 and 7.
Overall, catches were dominated by males, which represented 85.0% of the overall catch. Distinct trends were evident in the proportion of the catch represented by males and females in each region and these were relatively consistent across the five year study period. In particular, Regions 6 and 7 had a much higher percentage of females in the catch, 25.5% and 50.9% respectively compared to Regions 2, 3, 4 and 5 (9.6% to 17.6%).
Catch rates of male and female crabs varied between all regions. While catch rates differed among years within regions, differences among regions were generally consistent over the five year study period. Catch rates over the five year period were much higher in Region 4 than all other regions, reflecting the commercial catch data for the same period, which indicated highest catch rates in Region 4.
Analysis of catch rates with respect to the fishing depth and average bottom water temperature indicated that catches were highest at depths of 60 to 69 m for both male and female crabs. Catch rates of male and female crabs were variable with regards to bottom water temperature. However, these relationships were confounded by region to a large extent and were not consistently observed across all regions.
The LTMP spanner crab component, has delivered a time series of size and sex-ratio data coupled with fishery independent catch rate data for the five Queensland assessment regions in Commercial Fishery (Managed Area A). Similar data were collected from NSW in 2005 only, although only for a single year. Further standardization of the fishery independent catch rate with associated biological and physical characteristics will greatly enhance the importance of this data set for future analysis and regional population assessments
spanner
No full textspanner nOne Tom used to use - a great long gun,inch bore; that's the hammer,see, an' the spanner and trigger,look.YesDNE-cit J. D. A. WIDDOWSON AUG 1973(See OED _spanner sb�_)Used IUsed IUsed
Stable roommates spanner
No full textWe introduce a new geometric spanner whose construction is based on a generalization of the known Stable Roommates problem. The Stable Roommates Spanner combines the most desirable properties of geometric spanners: a natural definition, small degree, linear number of edges, strong (1+ε)-spanner for every ε>0, and an efficient construction algorithm. It is an improvement over the well-known Yao graph and Θ-graph and their variants. We show how to construct such a spanner for a set of points in the plane in O(n log10n) expected time. We introduce a variant of the Stable Roommates Spanner called the Stable Roommates Θ-Spanner which we can generalize to higher dimensions and construct more efficiently in O(n logdn) time. This variant possesses all the properties of the Stable Roommates Spanner except that it is no longer a strong spanner. © 2012 Elsevier B.V. All rights reserved.SCOPUS: cp.jinfo:eu-repo/semantics/publishe
Spanner Crab Fishery Level 1 Ecological Risk Assessment
Get PDFThe Queensland Ecological Risk Assessment Guideline (the Guideline) was released in March 2018 as part of the Queensland Sustainable Fisheries Strategy 2017–2027. This Guideline provides an overview of strategy being employed to develop Ecological Risk Assessments (ERAs) for Queensland’s fisheries. The Guideline describes a four-stage framework consisting of a Scoping Study; a Level 1, whole of fishery qualitative assessment; a Level 2, species-specific semi-quantitative or low-data quantitative assessment and; a Level 3 quantitative assessment (if applicable).
The aim of the Level 1 ERA is to produce a broad risk profile for each fishery based on a qualitative ERA method described by Astles et al. (2006). The method considers a range of factors including the current fishing environment (e.g. current catch, effort and licensing trends), limitations of the current management arrangements (e.g. transfer of effort to already saturated markets, substantial increases in fishing mortality for key species, changing target species) and life-history constraints of the species being assessed. In the Spanner Crab Fishery the Level 1 ERA assessed fishing related risks in 15 ecological components including target species, bycatch, marine turtles, sea snakes, crocodiles, dugongs, cetaceans (whales and dolphins), protected teleosts, batoids, sharks, syngnathids, seabirds, terrestrial mammals, marine habitats and ecosystem processes.
The Level 1 ERA indicates that the Spanner Crab Fishery presents a low to negligible risk to most of ecological components. At low/intermediate, target species had the highest risk rating of the assessment. These risks are being managed effectively through a range of measures including a fishery-specific harvest strategy
Computing the greedy spanner in linear space
No full textThe greedy spanner is a high-quality spanner: its total weight, edge count and maximal degree are asymptotically optimal and in practice significantly better than for any other spanner with reasonable construction time. Unfortunately, all known algorithms that compute the greedy spanner of n points use O(n2) space, which is impractical on large instances. To the best of our knowledge, the largest instance for which the greedy spanner was computed so far has about 13,000 vertices. We present a O(n)-space algorithm that computes the same spanner for points in Rd running in O(n2 log2n) time for any fixed stretch factor and dimension. We discuss and evaluate a number of optimizations to its running time, which allowed us to compute the greedy spanner on a graph with a million vertices. To our knowledge, this is also the first algorithm for the greedy spanner with a near-quadratic running time guarantee that has actually been implemented
Computing the greedy spanner in linear space
Get PDFThe greedy spanner is a high-quality spanner: its total weight, edge count and maximal degree are asymptotically optimal and in practice significantly better than for any other spanner with reasonable construction time. Unfortunately, all known algorithms that compute the greedy spanner of n points use O(n2) space, which is impractical on large instances. To the best of our knowledge, the largest instance for which the greedy spanner was computed so far has about 13,000 vertices.
We present a O(n)-space algorithm that computes the same spanner for points in Rd running in O(n2 log2n) time for any fixed stretch factor and dimension. We discuss and evaluate a number of optimizations to its running time, which allowed us to compute the greedy spanner on a graph with a million vertices. To our knowledge, this is also the first algorithm for the greedy spanner with a near-quadratic running time guarantee that has actually been implemented
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