scholarly journals Linking spatial stock dynamics and economics: evaluation of indicators and fishery management for the travelling eastern king prawn (Melicertus plebejus)

2014 ◽  
Vol 71 (7) ◽  
pp. 1818-1834 ◽  
Author(s):  
Michael F. O'Neill ◽  
George M. Leigh ◽  
You-Gan Wang ◽  
J. Matías Braccini ◽  
Matthew C. Ives
Keyword(s):  
Fishery Management ◽  
New South ◽  
Fishing Effort ◽  
Reference Points ◽  
Catch Rate ◽  
Decision Makers ◽  
Control Rules ◽  
South Wales ◽  
Strategy Evaluation ◽  
Dynamics Calculation

Abstract Reduced economic circumstances have moved management goals towards higher profit, rather than maximum sustainable yields in several Australian fisheries. The eastern king prawn is one such fishery, for which we have developed new methodology for stock dynamics, calculation of model-based and data-based reference points and management strategy evaluation. The fishery is notable for the northward movement of prawns in eastern Australian waters, from the State jurisdiction of New South Wales to that of Queensland, as they grow to spawning size, so that vessels fishing in the northern deeper waters harvest more large prawns. Bioeconomic fishing data were standardized for calibrating a length-structured spatial operating model. Model simulations identified that reduced boat numbers and fishing effort could improve profitability while retaining viable fishing in each jurisdiction. Simulations also identified catch rate levels that were effective for monitoring in simple within-year effort-control rules. However, favourable performance of catch rate indicators was achieved only when a meaningful upper limit was placed on total allowed fishing effort. The methods and findings will allow improved measures for monitoring fisheries and inform decision makers on the uncertainty and assumptions affecting economic indicators.

How useful is the ratio of fish density outside versus inside no-take marine reserves as a metric for fishery management control rules?

2011 ◽  
Vol 68 (2) ◽  
pp. 343-359 ◽  
Author(s):  
Elizabeth A. Babcock ◽  
Alec D. MacCall
Keyword(s):  
Fishery Management ◽  
Spatial Scales ◽  
Marine Reserves ◽  
Density Ratio ◽  
Relative Weight ◽  
Fishing Effort ◽  
Management Control ◽  
Fish Density ◽  
Control Rules ◽  
Stock Depletion

A management strategy evaluation (based on five species in the California, USA, nearshore fishery) of control rules that reduce relative fishing effort as a function of the ratio of fish density outside versus inside no-take marine reserves (as a measure of depletion) showed that although the control rules allowed effort to increase at first, in the long term, they were effective at maintaining spawning stock biomass and yield for all simulated species, including depleted ones. Scenarios with fish movement, illegal fishing in the reserve, or post-dispersal density dependence in recruitment required higher density ratio targets, such as 60% of mature fish or 80% of all fish, to avoid stock depletion. The effort allowed by multispecies density-ratio control rules depended on the relative weight given to more or less depleted species. High variability in recruitment or in monitoring data caused the allowable effort to fluctuate. Density-ratio control rules have the advantages that they require no historical data, they can be used at local spatial scales, and they adjust to changing environmental conditions.

The 1999 review of the Western Division of New South Wales

2001 ◽  
Vol 23 (1) ◽  
pp. 33 ◽  
Author(s):  
John Kerin
Keyword(s):  
Natural Resource Management ◽  
Social Issues ◽  
New South ◽  
New South Wales ◽  
Decision Makers ◽  
Comprehensive Review ◽  
South Wales ◽  
Technological Advances ◽  
Administrative Procedures ◽  
Western Division

A comprehensive review of the Western Division of New South Wales was carried out in 1998/99. The review addressed economic, environmental and social issues in New South Wales' rangelands. Six commissioned studies examined these issues in more detail. The recommendations of the review centred on streamlining administrative procedures, including Acts and regulations, addressing integrated natural resource management from a regional perspective by involving leaseholders and relevant stakeholders as representative of the broader community. It was seen as essential that scientific research and expertise, and technological advances in knowledge, be utilised by decision makers in coming to more coordinated land management decisions.

scholarly journals Performance evaluation of harvest control rules for Pacific herring management in British Columbia, Canada

2010 ◽  
Vol 67 (9) ◽  
pp. 2005-2011 ◽  
Author(s):  
J. S. Cleary ◽  
S. P. Cox ◽  
J. F. Schweigert
Keyword(s):  
British Columbia ◽  
Performance Evaluation ◽  
Reference Point ◽  
Fishery Management ◽  
Reference Points ◽  
Management Policy ◽  
Pacific Herring ◽  
High Productivity ◽  
Control Rules ◽  
Harvest Control Rules

Abstract Cleary, J. S., Cox, S. P., and Schweigert, J. F. 2010. Performance evaluation of harvest control rules for Pacific herring management in British Columbia, Canada. – ICES Journal of Marine Science, 67: 2005–2011. Despite application of a harvest control rule (HCR) since 1986, abundance of several Pacific herring (Clupea pallasi) stocks in British Columbia, Canada, are currently below levels considered adequate for exploitation. An alternative HCR, based on default limit and upper stock reference (USR) points at 0.4 BMSY and 0.8 BMSY, was recently developed under Canada's precautionary fisheries management policy. We simulated the Pacific herring fishery management system to examine whether (i) realized fishery performance over the past 10 years is an expected consequence of applying the existing herring HCR (with a single lower reference point) and (ii) performance could be improved by adopting the Department of Fisheries and Oceans new HCR with limit and USR points. Both HCRs successfully rebuilt stocks to sustainable levels under a high-productivity scenario, but performed poorly when stock productivity was low. The two HCRs were sensitive to stock productivity, because the effect of a target harvest rate (20%) that is independent of productivity was much larger than the effects of biomass reference-point choices. We therefore recommend further research on estimating reference points and sustainable harvest rates for Pacific herring, so that HCRs may be made more responsive to changes in productivity.

Systems modelling and simulation to inform strategic decision making for suicide prevention in rural New South Wales (Australia)

2020 ◽  
Vol 54 (9) ◽  
pp. 892-901 ◽  
Author(s):  
Jo-An Atkinson ◽  
Adam Skinner ◽  
Sue Hackney ◽  
Linda Mason ◽  
Mark Heffernan ◽  
...  
Keyword(s):  
Mental Health ◽  
Decision Making ◽  
Suicide Prevention ◽  
Suicidal Behaviour ◽  
New South ◽  
Decision Makers ◽  
Evidence Based ◽  
South Wales ◽  
Self Harm ◽  
Systems Modelling

Background: The need to understand and respond to the unique characteristics and drivers of suicidal behaviour in rural areas has been enabled through the Australian Government’s 2015 mental health reforms facilitating a move to an evidence-based, regional approach to suicide prevention. However, a key challenge has been the complex decision-making environment and lack of appropriate tools to facilitate the use of evidence, data and expert knowledge in a way that can inform contextually appropriate strategies that will deliver the greatest impact. This paper reports the co-development of an advanced decision support tool that enables regional decision makers to explore the likely impacts of their decisions before implementing them in the real world. Methods: A system dynamics model for the rural and remote population catchment of Western New South Wales was developed. The model was based on defined pathways to mental health care and suicidal behaviour and reproduced historic trends in the incidence of attempted suicide (self-harm hospitalisations) and suicide deaths in the region. A series of intervention scenarios were investigated to forecast their impact on suicidal behaviour over a 10-year period. Results: Post-suicide attempt assertive aftercare was forecast to deliver the greatest impact, reducing the numbers of self-harm hospitalisations and suicide deaths by 5.65% (95% interval, 4.87−6.42%) and 5.45% (4.68−6.22%), respectively. Reductions were also projected for community support programs (self-harm hospitalisations: 2.83%, 95% interval 2.23−3.46%; suicide deaths: 4.38%, 95% interval 3.78−5.00%). Some scenarios produced unintuitive impacts or effect sizes that were significantly lower than what has been anticipated under the traditional evidence-based approach to suicide prevention and provide an opportunity for learning. Conclusion: Systems modelling and simulation offers significant potential for regional decision makers to better understand and respond to the unique characteristics and drivers of suicidal behaviour in their catchments and more effectively allocate limited health resources.

Changes in relative abundance of sharks and rays on Australian South East Fishery trawl grounds after twenty years of fishing

2001 ◽  
Vol 52 (4) ◽  
pp. 549 ◽  
Author(s):  
K. J. Graham ◽  
N. L. Andrew ◽  
K. E. Hodgson
Keyword(s):  
New South ◽  
Early Years ◽  
Catch Rate ◽  
Depth Range ◽  
South Wales ◽  
Sampling Protocols ◽  
Species Groups ◽  
The Mean ◽  
Low Levels ◽  
Catch Rates

Upper continental slope trawling grounds (200–650 m depth) off New South Wales were surveyed with the same vessel and trawl gear and similar sampling protocols in 1976–77 (during the early years of commercial exploitation) and in 1996–97. The 1996–97 mean catch rate of sharks and rays, pooled for the main 15 species (or species groups), was ~20% of the 1976–77 mean. Individual catch rates were substantially lower in 1996–97 for 13 of the 15 species or species groups. The greatest decline was observed for dogsharks of the genus Centrophorus, which were most abundant in 1976–77 but rarely caught 20 years later. In contrast, 1996–97 catch rates of spiky dogshark (Squalus megalops) and, to a lesser extent, whitefin swell shark (Cephaloscyllium sp. A) were similar to those in 1976–77. Trawling during 1979–81 provided data for nine species, albeit not corrected for larger gear size, and the pooled mean catch rate for sharks and rays in the depth range 300–525 m was ~28% of the mean for 1976–77. The results suggest that the biomass of most species of sharks and rays declined rapidly as the fishery developed and is now at very low levels.

The New South Wales Trawlfishery: Review of Past Course and Examination of Present Condition

1955 ◽  
Vol 6 (2) ◽  
pp. 165 ◽  
Author(s):  
TW Houston
Keyword(s):  
New South ◽  
New South Wales ◽  
Size Composition ◽  
Fishing Effort ◽  
Present Condition ◽  
Catch Per Unit Effort ◽  
Nineteen Thirties ◽  
Unit Effort ◽  
South Wales ◽  
Post War

The past course of the New South Wales mixed trawlfishery is reviewed mainly on the basis of the available catch and fishing effort statistics. The size composition of tiger flathead landings from 1946-47 to 1953-54, and the age composition for certain post-war years, are analysed in conjunction with catch per unit effort data. The results suggest that 1943-44, 1944-45, 1947-48, and 1948-49 were relatively poor brood years, and 1945-46 and 1946-47 relatively good. The fluctuations in availability of tiger flathead (Neoplatycephalus macrodon (Ogilby) ) are accounted for after making certain valid assumptions. It is considered probable that the unexpectedly low catches of tiger flathead in the immediate post-war years were due to inefficiency of the few steam trawlers then working, and that Danish seiners were unable to exploit fully the available V+ and higher age-group fish. An examination of the present situation indicates that the New South Wales stock of tiger flathead is at a low level and is likely to reach even lower levels in the future if fishing intensity remains as high as in 1953-54. An improvement of the existing catch per unit effort would be expected if fishing intensity was reduced to the level of the middle nineteen-thirties (i.e. approx. 3500 trawler-tons) . Other regulative measures would need to be introduced to bring about an improvement in the annual catch of tiger flathead. These measures should aim at ensuring a more favourable weight-length relation.

scholarly journals Validation of a feedback harvest control rule in data-limited conditions for managing multispecies fisheries

2019 ◽  
Vol 76 (10) ◽  
pp. 1885-1893 ◽  
Author(s):  
Ledhyane Ika Harlyan ◽  
Dengke Wu ◽  
Ryosuke Kinashi ◽  
Methee Kaewnern ◽  
Takashi Matsuishi
Keyword(s):  
Fisheries Management ◽  
Fishery Management ◽  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Mixed Species ◽  
Multispecies Fisheries ◽  
Strategy Evaluation ◽  
Sustainable Fishery ◽  
Species Specific ◽  
Slow Growing

Harvest control rules (HCRs) for sustainable fishery management have been developed for data-limited fish species for which stock assessments cannot be conducted. However, HCRs have largely not considered mixed-species catches, as when fishing-effort data are widely pooled for numerous minor species in a multispecies fishery. Presently, a feedback HCR has been successfully applied in Japanese fisheries management. By combining management strategy evaluation with a simulation to generate mixed-species data from a multispecies fishery that assume constant catchability (q) among species, we evaluated the performance of this feedback HCR and then compared its performance using species-specific data. In most cases, the biomass was controlled over that needed for maximum sustainable yield (MSY), and the fishing effort was under the fishing mortality consistent with achieving MSY (FMSY). However, for slow-growing species, the biomass might become lower than what is required to remain capable of producing MSY, even though fishing effort was controlled under FMSY. The results show that the feedback HCR is appropriate for multispecies fisheries management where only mixed-species data are available but with special monitoring for slow-growing minor species.

Populations of Barracouta, Thyrsites atun (Euphrasen), in Australian Waters.

1954 ◽  
Vol 5 (3) ◽  
pp. 411 ◽  
Author(s):  
M Blackburn ◽  
PE Gartner
Keyword(s):  
Coastal Waters ◽  
New South ◽  
South Australia ◽  
Size Composition ◽  
Fishing Effort ◽  
South Wales ◽  
Different Populations ◽  
Australian Fish ◽  
Western Victoria ◽  
Autumn And Winter

Different populations of barracouta (Scombriformes: Acinaceidae), the principal Australian fish of commerce, have been recognized by a study of differences in the following: spawning season; size composition of adult stock; and seasonal movements and annual fluctuations as revealed by records of catch and fishing effort. Tagging experiments gave little information because of the low rate of commercial exploitation of the populations. There are probably five populations in southern coastal waters, which make migrations to certain areas as follows: one in winter and spring to eastern Victoria and southern New South Wales, one from spring to autumn to Bass Strait and its western approaches, one in summer and autumn to eastern Tasmania, one in autumn and winter to South Australia and western Victoria, and one (possibly not distinct from the previous population) in autumn and winter to the south coast of Western Australia. Spawning and feeding take place in the course of these migrations. Little is known about the populations when they are not migrating, but the three first-mentioned groups all appear to seek the neighbourhood of eastern Bass Strait between the migratory seasons. The fish prefer waters of about 13-180C and tend to vacate areas when they become cooler or warmer than this. Only the Bass Strait and eastern Tasmanian populations are significantly fished and the size of the catches is generally governed by the demand. However, there have been occasional years of scarcity, such as 1950-51 and 1951-52 in Bass Strait and 1951-52 in eastern Tasmania. These represent natural fluctuations (there is no evidence of depletion of any population) and for the Bass Strait population they are probably fluctuations in availability in the fishing areas rather than in abundance of the whole population. It is considered that the combined Australian populations could yield 10 times as much as the present annual catch of 6,000,000 Ib (beheaded and cleaned) when fluctuations were not adverse.

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