scholarly journals Scenario testing of fisheries management strategies using a high resolution ERSEM–POM ecosystem model

2007 ◽  
Vol 64 (9) ◽  
pp. 1627-1640 ◽  
Author(s):  
G. Petihakis ◽  
C. J. Smith ◽  
G. Triantafyllou ◽  
G. Sourlantzis ◽  
K-N. Papadopoulou ◽  
...  
Keyword(s):  
High Resolution ◽  
Fisheries Management ◽  
Management Strategies ◽  
Ecosystem Model ◽  
Ecosystem Models ◽  
Management Scenarios ◽  
Management Tools ◽  
Cost Impact ◽  
The Cost ◽  
Scenario Testing

Abstract Petihakis, G., Smith, C. J., Triantafyllou, G., Sourlantzis, G., Papadopoulou, K-N., Pollani, A., and Korres, G. 2007. Scenario testing of fisheries management strategies using a high resolution ERSEM–POM ecosystem model. – ICES Journal of Marine Science, 64: 1627–1640. Ecosystem models are just beginning to be considered as management tools. In terms of fishery impacts, dynamic ecosystem models provide an opportunity to make advances because they can both evaluate the state of the system and make predictions about the ecosystem under various fishing scenarios. In the framework of the Cost Impact project, a complex high-resolution (500 × 500 m grid) ecosystem model was implemented in Iraklion Bay, Crete. Several management scenarios were simulated to investigate the impacts of trawling on this particular ecosystem (reductions in fishing area, effort, and mortality). Introducing trawling impacts into the model led to increases in pelagic production. All scenarios also resulted in net increases in pelagic production, the level of which, and the degree of spatial variability, was dependent on the particular scenario. Changes in pelagic variables were often noted in areas well away from trawled areas. It was also clear that for pelagic variables and processes, depth of trawling is more important than reduction in trawling area, i.e. a scenario banning fishing in waters shallower than 100 m seems to lead to less change in the pelagic system than a scenario that reduces direct mortality to the benthos.

The Estimated Cost of Managing Focal Spasticity: A Physician Practice Patterns Survey

2001 ◽  
Vol 15 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Paul W. Radensky ◽  
Jennifer W. Archer ◽  
Susan F. Dournaux ◽  
Christopher F. O'Brien
Keyword(s):  
Botulinum Toxin ◽  
Practice Patterns ◽  
Botulinum Toxin Type A ◽  
Management Strategies ◽  
Type A ◽  
Botulinum Toxin Type ◽  
Individual Treatment ◽  
Cost Impact ◽  
Treat Ment ◽  
The Cost

The purpose of this study was to estimate the overall cost of managing focal spas ticity after stroke (CVA) and traumatic brain injury (TBI) and the cost impact of in dividual treatments. Sixty physicians described management strategies over six treat ment visits for four focal spasticity case studies (one upper and one lower extremity case for CVA and TBI). Mean and median per-case costs were determined across physi cians ; median per-case costs of physicians who did or did not report use of specific treat ments were compared. Mean per-case costs of managing spasticity are as follows: CVA upper, $5,131; CVA lower, $5,384; TBI upper, $14,615; and TBI lower, $13,966. Me dian per-case costs for strategies including botulinum toxin type A (BTX-A) were less than those without BTX-A in CVA upper; median costs for strategies including oral baclofen were more than those without baclofen in CVA lower. Fewer total treat , ments were reported with BTX-A than without; more total treatments were reported with baclofen than without. No individual treatment had a significant impact on me dian treatment costs in TBI. Physician-reported spasticity management costs are sub stantial. Despite higher drug costs for BTX-A compared with oral therapies like ba clofen, strategies for managing spasticity in CVA that include BTX-A may cost less than those without BTX-A. Key Words: Spasticity—Stroke—Traumatic brain in jury—Botulinum toxin type A—Baclofen.

scholarly journals Evaluation of current and alternative fisheries management scenarios based on spawning-per-recruit (SPR), revenue-per-recruit (RPR), and yield-per-recruit (YPR) diagrams

2005 ◽  
Vol 62 (5) ◽  
pp. 841-846 ◽  
Author(s):  
T. Katsukawa
Keyword(s):  
Fisheries Management ◽  
Numerical Optimization ◽  
Management Strategy ◽  
Management Strategies ◽  
Management Scenarios ◽  
Trade Off ◽  
Contour Lines ◽  
Stock Assessments ◽  
Optimal Harvest ◽  
Yield Per Recruit

Abstract Spawning-per-recruit (SPR) and yield-per-recruit (YPR) analyses are widely used in stock assessments of exploited fish populations. In decision-making for fisheries management, the trade-off between fisheries production (YPR) and stock reproduction (SPR) is important. The general outputs of SPR and YPR analysis, such as single variate plots with contour lines or optimal harvest strategies estimated by numerical optimization, are inappropriate in obtaining an overview of the trade-off. This paper introduces a diagram that expresses graphically the bivariate trade-off between YPR and SPR. The method was applied to chub mackerel (Scomber japonicus) data, and two management scenarios were compared using the SPR–YPR diagram. Differences between YPR and revenue-per-recruit (RPR) were also considered. The results showed that: (i) current estimated fishing mortality is suggestive of growth-overfishing, and there is room for improving SPR and YPR simultaneously; (ii) increasing the age at first capture is more effective than effort control; (iii) management strategies that maximize landing weight or revenue are significantly different. The management strategy that maximizes landing weight, when considered from the viewpoint of maximizing revenue, results in growth-overfishing.

scholarly journals The dual role of indicators in optimal fisheries management strategies

2007 ◽  
Vol 64 (4) ◽  
pp. 775-778 ◽  
Author(s):  
Jake C. Rice ◽  
Denis Rivard
Keyword(s):  
Fisheries Management ◽  
Integrated Management ◽  
Management Strategies ◽  
Management Plan ◽  
Dual Role ◽  
Management Tools ◽  
Control Functions ◽  
Control Rules ◽  
Spawning Stock

Abstract Rice, J. C., and Rivard, D. 2007. The dual role of indicators in optimal fisheries management strategies. – ICES Journal of Marine Science, 64: 775–778. Indicators are used in two different ways in the assessment and advisory cycle. One is to audit performance of the management plan relative to achieving the objectives for the fishery. The second is to trigger control rules to manage the subsequent harvest. Traditionally, the assessment and management community has used spawning-stock biomass and fishing mortality for these functions, and as management strategies are being developed, generally continues to test the same indicators in both the audit and control functions. There is no reason to use the same indicators in both functions, and management of a few specialized commercial fisheries has recognized this, using different indicators in different roles for many years. That different indicators may be optimal for both roles presents a richer range of opportunities for exploring robust management strategies, and will be essential as ecosystem considerations and integrated management tools are included in assessment and management.

scholarly journals Assessing the adequacy of current fisheries management under changing climate: a southern synopsis

2011 ◽  
Vol 68 (6) ◽  
pp. 1305-1317 ◽  
Author(s):  
Éva E. Plagányi ◽  
Scarla J. Weeks ◽  
Tim D. Skewes ◽  
Mark T. Gibbs ◽  
Elvira S. Poloczanska ◽  
...  
Keyword(s):  
Climate Change ◽  
Fisheries Management ◽  
Environmental Changes ◽  
Stock Assessment ◽  
Management Strategies ◽  
Single Species ◽  
Rock Lobster ◽  
Management Tools ◽  
Changing Climate ◽  
Impacts Of Climate Change

Abstract Plagányi, É. E., Weeks, J. S., Skewes, T. D., Gibbs, M. T., Poloczanska, E. S., Norman-López, A., Blamey, L. K., Soares, M., and Robinson, W. M. L. 2011. Assessing the adequacy of current fisheries management under changing climate: a southern synopsis. – ICES Journal of Marine Science, 68: 1305–1317. Climate change is likely to have a significant impact on both target and non-target marine stocks worldwide, with the concomitant need for management strategies capable of sustaining fishing in future. We use several southern hemisphere fisheries to highlight the likely impacts of climate change at a range of levels, from individual to population responses, as well as ecosystem ramifications. Examples span polar (Antarctic krill fishery), temperate (west coast pelagic fishery, abalone and rock lobster), and tropical (Torres Strait rock lobster) commercially important fisheries. Responses of these fisheries to either past observed environmental changes or projected future changes are used to deduce some anticipated implications of climate change for fisheries management, including economic impacts and governance considerations. We evaluate the effectiveness of current single-species assessment models, management strategy evaluation approaches and multispecies assessment models as future management tools to cope with likely climate-related changes. Non-spatial stock assessment models will have limited ability to separate fishery effects from the impacts of climate change. Anthropogenic climate change is occurring at a time-scale relevant to current fisheries management strategic planning and testing. Adaptive management frameworks (with their feedback loops) are ideal for detecting and adapting to changes in target stocks.

scholarly journals Diversification insulates fisher catch and revenue in heavily exploited tropical fisheries

2020 ◽  
Vol 6 (8) ◽  
pp. eaaz0587 ◽  
Author(s):  
James P. W. Robinson ◽  
Jan Robinson ◽  
Calvin Gerry ◽  
Rodney Govinden ◽  
Cameron Freshwater ◽  
...  
Keyword(s):  
High Resolution ◽  
Fisheries Management ◽  
Management Strategies ◽  
Fishing Effort ◽  
Marine Resources ◽  
Nutritional Security ◽  
Fishing Vessels ◽  
Species Groups ◽  
Catch Rates ◽  
Average Catch

Declines in commercial landings and increases in fishing fleet power have raised concerns over the continued provisioning of nutritional and economic services by tropical wild fisheries. Yet, because tropical fisheries are often data-poor, mechanisms that might buffer fishers to declines are not understood. This data scarcity undermines fisheries management, making tropical fishing livelihoods particularly vulnerable to changes in marine resources. We use high-resolution fisheries data from Seychelles to understand how fishing strategy (catch diversification) influences catch rates and revenues of individual fishing vessels. We show that average catch weight decreased by 65% over 27 years, with declines in all nine species groups coinciding with increases in fishing effort. However, for individual vessels, catch diversity was associated with larger catches and higher fishing revenues and with slower catch declines from 1990 to 2016. Management strategies should maximize catch diversity in data-poor tropical fisheries to help secure nutritional security while protecting fishing livelihoods.

scholarly journals A simulation-based approach to assess sensitivity and robustness of fisheries management indicators for the pelagic fishery in the Bay of Biscay

2013 ◽  
Vol 70 (12) ◽  
pp. 1741-1756 ◽  
Author(s):  
Sigrid Lehuta ◽  
Stéphanie Mahévas ◽  
Pascal Le Floc’h ◽  
Pierre Petitgas
Keyword(s):  
Fisheries Management ◽  
Mechanistic Model ◽  
Management Strategies ◽  
Bay Of Biscay ◽  
Management Scenarios ◽  
Management Performance ◽  
Metric Properties ◽  
Sensitivity Indices ◽  
Major Factors ◽  
Pelagic Fishery

Indicators are widely promoted as means to monitor ecosystem status or to evaluate fisheries management performance. “Which indicators are most relevant as decision-support tools in fisheries management?” still remains a topical question. Indicators should be metrics related to fish populations and fleets and should be sensitive to management strategies. However, given the complexity of the processes involved, it is often difficult to unequivocally interpret variations in metrics. A simulation approach was used to study metric properties and to identify robust and relevant fishery indicators. By applying sensitivity analysis methods, simulation designs were built that cross a variety of management scenarios and uncertainty hypotheses. Bio-economic outputs were simulated using a mechanistic model (ISIS-Fish), and their properties were statistically analyzed. This approach was applied to the pelagic fishery of the Bay of Biscay. The analysis of metric properties highlighted the major factors driving variations in each metric and identified the important sources of uncertainty that need to be reduced to allow the use of metrics as indicators. Although very few metrics gave robust indications of management performance, sensitivity indices evidenced how management performances could be improved, and spatially disaggregated metrics provided insights into the mechanisms underlying management performance.

Addressing on-farm management to enhance pasture productivity and persistence

2013 ◽  
pp. 241-244
Author(s):  
W.N. Reynolds
Keyword(s):  
Management Strategies ◽  
Dairy Farm ◽  
Stocking Rate ◽  
Pasture Management ◽  
Pasture Production ◽  
Operating Profit ◽  
The North ◽  
The Cost ◽  
On Farm ◽  
Attention To Detail

Following the 2007/08 drought, we experienced poor pasture production and persistence on our dairy farm in north Waikato, leading to decreased milksolids production and a greater reliance on bought-in feed. It is estimated that the cost of this to our farming operation was about $1300 per hectare per year in lost operating profit. While climate and black beetle were factors, they did not explain everything, and other factors were also involved. In the last 3 years we have changed our management strategies to better withstand dry summers, the catalyst for which was becoming the DairyNZ Pasture Improvement Focus Farm for the north Waikato. The major changes we made were to reduce stocking rate, actively manage pastures in summer to reduce over-grazing, and pay more attention to detail in our pasture renewal programme. To date the result has been a reduced need for pasture renewal, a lift in whole farm performance and increased profitability. Keywords: Focus farm, over-grazing, pasture management, pasture persistence, profitability

Wastewater management strategies for the black sea coast of Turkey

1999 ◽  
Vol 39 (8) ◽  
pp. 169-176
Author(s):  
I. Ozturk ◽  
E. Yuksel ◽  
A. Tanik
Keyword(s):  
Black Sea ◽  
Management Strategy ◽  
Population Distribution ◽  
Management Strategies ◽  
The Black Sea ◽  
Wastewater Management ◽  
Black Sea Coast ◽  
The Cost ◽  
Solid Waste Landfills ◽  
Sea Coast

The Black Sea, surrounded by six riparian countries, is under the threat of severe pollution, giving rise to the need of taking precautions to protect it from further deterioration. In this paper, an effort putting forth a wastewater treatment and management strategy is outlined for the Black Sea coast of Turkey, including both the technical and financial aspects. The present situation of the coast in terms of land-based pollution and infrastructure is stated, followed by an applicable management strategy. The strategy developed for the coastal settlements involves various stagewise treatment schemes based on population distribution and densities along the coastline, and on the availability of land in a specified period of thirty years. Similar strategies are proposed for the control of pollution originating from industries, for those carried by rivers joining the sea, and for leachate of solid waste landfills. The cost estimations of various treatment schemes are also given in terms of population equivalents.

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