scholarly journals An evaluation of acceptable biological catch (ABC) harvest control rules designed to limit overfishing

2017 ◽  
Vol 74 (7) ◽  
pp. 1028-1040 ◽  
Author(s):  
John Wiedenmann ◽  
Michael Wilberg ◽  
Andrea Sylvia ◽  
Thomas Miller
Keyword(s):  
Fishery Management ◽  
Short Interval ◽  
Assessment Model ◽  
Scientific Uncertainty ◽  
High Yield ◽  
Management Objectives ◽  
Control Rules ◽  
Average Biomass ◽  
Harvest Control Rules

In this paper we developed a simulation model to evaluate a range of acceptable biological catch (ABC) control rules to determine their relative performance at achieving common fishery management objectives. We explored a range of scenarios to determine robustness of a control rule to different situations and found that across scenarios the control rules that used a buffer to account for scientific uncertainty when setting the ABC were able to limit the frequency of overfishing. Modest buffers when setting the ABC were generally effective at limiting overfishing, but larger buffers resulted in higher average biomass, similar long-term benefits to the fishery (high yield, low variability in yield), more rapid recovery of depleted populations, and a lower risk of the population being overfished, and these results were robust to the level of uncertainty in the assessment model estimates. In addition, fixing the ABC over the interval between assessments and having a short interval between assessments was generally more effective at meeting management objectives than using projections and having a long assessment interval.

scholarly journals Objectives and harvest control rules in the management of the fishery of Norwegian spring-spawning herring

2009 ◽  
Vol 66 (8) ◽  
pp. 1793-1799 ◽  
Author(s):  
Sigurd Tjelmeland ◽  
Ingolf Røttingen
Keyword(s):  
Stock Assessment ◽  
Maximum Sustainable Yield ◽  
Assessment Model ◽  
Main Element ◽  
Management Objectives ◽  
Control Rules ◽  
Harvest Control Rule ◽  
Stock Recruitment ◽  
Harvest Control Rules

Abstract Tjelmeland, S., and Røttingen, I. 2009. Objectives and harvest control rules in the management of the fishery of Norwegian spring-spawning herring. – ICES Journal of Marine Science, 66: 1793–1799. The main element in the management of the Norwegian spring-spawning herring, as implemented by the coastal states, is to conduct the fishery based on a maximum fishing mortality (F) of 0.125. As the appropriateness of this rule (given the stated objectives) has not yet been tested thoroughly, we set out to do this by long-term simulations, in which we applied a range of alternative stock–recruitment relationships. These different relationships are estimated from historical replicates of the stock, as calculated by the herring-stock assessment model SeaStar. During prognostic simulations, a recruitment model is selected probabilistically for each historical replicate based on Akaike weights. We evaluate whether the management objectives are met by applying the present harvest control rule. Results are given for the current assessment option of natural mortality (M = 0.5) in the oldest aggregated age group and for the assessment option used in 2005 and earlier (M = 0.15). These show that perceptions of the long-term yield differ considerably and that the current management is somewhat on the conservative side from the perspective of maximum sustainable yield.

scholarly journals Implementing the precautionary approach into fisheries management: Making the case for probability-based harvest control rules

2020 ◽  
Author(s):  
Tobias K. Mildenberger ◽  
Casper W. Berg ◽  
Alexandros Kokkalis ◽  
Adrian R. Hordyk ◽  
Chantel Wetzel ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Reference Points ◽  
Production Model ◽  
Scientific Uncertainty ◽  
Precautionary Approach ◽  
Control Rules ◽  
Stock Biomass ◽  
Harvest Control Rules

AbstractThe precautionary approach to fisheries management advocates for risk-averse management strategies that include biological reference points as well as decision rules and account for scientific uncertainty. In this regard, two approaches have been recommended: (i) harvest control rules (HCRs) with threshold reference points to safeguard against low stock biomass, and (ii) the P* method, a ‘probability-based HCR’ that reduces the catch limit as a function of scientific uncertainty (i.e. process, model, and observation uncertainty). This study compares the effectiveness of these precautionary approaches in recovering over-exploited fish stocks with various life-history traits and under a wide range of levels of scientific uncertainty. We use management strategy evaluation based on a stochastic, age-based operating model with quarterly time steps and a stochastic surplus production model. The results show that the most effective HCR includes both a biomass threshold as well as the P* method, and leads to high and stable long-term yield with a decreased risk of low stock biomass. For highly dynamics stocks, management strategies that aim for higher biomass targets than the traditionally used BMSY result in higher long-term yield. This study makes the case for probability-based HCRs by demonstrating their benefit over deterministic HCRs and provides a list of recommendations regarding their definition and implementation.

scholarly journals Institutional designs to face the dark side of total allowable catches

2007 ◽  
Vol 64 (4) ◽  
pp. 851-857 ◽  
Author(s):  
Ikerne del Valle ◽  
Kepa Astorkiza
Keyword(s):  
Dark Side ◽  
Policy Makers ◽  
Control Rules ◽  
Opportunistic Behaviour ◽  
Self Interest ◽  
Conflicting Interests ◽  
Endogenous Process ◽  
Harvest Control Rules ◽  
Stock Abundance

Abstract del Valle, I., and Astorkiza, K. 2007. Institutional designs to face the dark side of total allowable catches. – ICES Journal of Marine Science, 64: 851–857. Setting total allowable catches (TACs) is an endogenous process in which different agents and institutions, often with conflicting interests and opportunistic behaviour, try to influence policy-makers. Far from being the benevolent social planners many would wish them to be, these policy-makers may also pursue self-interest when making final decisions. Although restricted knowledge of stock abundance and population dynamics, and weakness in enforcement, have effects, these other factors may explain why TAC management has failed to guarantee sustainable exploitation of fish resources. Rejecting the exogeneity of the TAC and taking advantage of fruitful debate on economic policy (i.e. the rules vs. discretion debate, and that surrounding the independence of central banks), two institutional developments are analysed as potential mechanisms to face up to misconceptions about TACs: long-term harvest control rules and a central bank of fish.

Responsive harvest control rules provide inherent resilience to adverse effects of climate change and scientific uncertainty

2019 ◽  
Vol 76 (6) ◽  
pp. 1424-1435 ◽  
Author(s):  
J P Kritzer ◽  
C Costello ◽  
T Mangin ◽  
S L Smith
Keyword(s):  
Climate Change ◽  
Adverse Effects ◽  
Biomass Yield ◽  
The United States ◽  
Scientific Uncertainty ◽  
Fish Stock ◽  
Fishing Mortality ◽  
Climate Effects ◽  
Control Rules ◽  
Harvest Control Rules

Abstract Climate change is altering marine ecosystem and fish stock dynamics worldwide. These effects add to scientific uncertainties that compromise fisheries management. Among the strategies that can respond to climate change and scientific uncertainty, modifications to harvest control rules (HCRs) might be among the most direct and impactful. We used a bioeconomic model to compare alternative HCRs in terms of biomass, yield, and profits in response to potential effects of climate change and scientific uncertainty, specifically simulated retrospective patterns, for 14 stocks on the Northeast Shelf of the United States. Our results suggest that a responsive HCR in which fishing mortality changes with measured changes in biomass builds inherent resilience to adverse effects of both climate change and scientific uncertainty relative to an HCR in which fishing mortality is precautionary but fixed. This was despite that fact that the HCR algorithm did not account for the climate effects modelled. A fixed fishing mortality HCR was effective when climate effects were negligible or beneficial. Scientific uncertainty further reduced biomass, yield, and profits by about the same magnitude as climate change. Our results suggest that simple changes to HCRs can be a readily implementable strategy for responding to climate change and scientific uncertainty.

scholarly journals Changing attitudes 1970–2012: evolution of the Norwegian management framework to prevent overfishing and to secure long-term sustainability

2013 ◽  
Vol 71 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Peter Gullestad ◽  
Asgeir Aglen ◽  
Åsmund Bjordal ◽  
Geir Blom ◽  
Sverre Johansen ◽  
...  
Keyword(s):  
National Level ◽  
Management Tools ◽  
Management Framework ◽  
Rational Decision Making ◽  
Control Rules ◽  
Gradual Development ◽  
Changing Attitudes ◽  
Economic Zones ◽  
Harvest Control Rules

Abstract Gullestad, P., Aglen, A., Bjordal, Å., Blom, G., Johansen, S., Krog, J., Misund, O. A., and Røttingen, I. 2014. Changing attitudes 1970–2012: evolution of the Norwegian management framework to prevent overfishing and to secure long-term sustainability. – ICES Journal of Marine Science, 71: 173–182. Fisheries have been important for livelihood in Norwegian coastal communities for centuries. The development of new fishing technology and increasing fishing capacity posed challenges for the sustainability of the fisheries. The Norwegian spring spawning herring was depleted in the1960s—with dire consequences. This event, and the subsequent efforts to rebuild the stock, was paramount to the gradual development of a coherent Norwegian policy to prevent overfishing and secure long-term sustainability. Nevertheless, overfishing continued during the ensuing transitional decades when a range of new management tools were developed and made effective. Internationally, the extension of the economic zones to 200 nautical miles, and agreement on sharing and management of joint stocks were important elements. At the national level, the development of measures to curb overcapacity, improvement of exploitation patterns through technical regulations, ban on discard and the evolution of procedures for rational decision-making for setting total allowable catches (TACs) on the basis of harvest control rules, were all decisive elements. Another crucial factor was the creation of a whole new profession of fishery inspection. We describe a system of close collaboration between specialists—scientists, fishery managers, and stakeholders—each with a distinct role in building a solid framework to prevent overfishing and secure long-term sustainability.

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.

scholarly journals Rebuilding depleted fisheries towards BMSY under uncertainty: harvest control rules outperform combined management measures

2020 ◽  
Author(s):  
Ming Sun ◽  
Yunzhou Li ◽  
Yiping Ren ◽  
Yong Chen
Keyword(s):  
Management Practices ◽  
Maximum Sustainable Yield ◽  
Natural Mortality ◽  
Short Term ◽  
Sources Of Uncertainty ◽  
Control Rules ◽  
Management Measures ◽  
Strategy Evaluation ◽  
Harvest Control Rules

Abstract Rebuilding depleted fisheries towards sustainable levels, such as BMSY, is challenging under uncertainty. Although a substantial amount of research has highlighted the importance of accounting for uncertainty in fisheries management, tactical measures remain to be identified. We consider two approaches to achieve this goal: (i) the naive maximum sustainable yield (MSY) approach, combining management measures based on effort control, catch quotas, and spatial–temporal closures, and (ii) the harvest control rules (HCRs) approach, developing HCRs based on short-term or long-term targets. A suite of strategies is developed accordingly and tested with management strategy evaluation for their performance under four sources of uncertainty that may negatively impact management effects, including reduced recruitment strength, increased natural mortality, inadequate implementation error, and varying levels of temporal effort aggregation. Combining management measures using the naive MSY approach is found to perform poorly in tackling uncertainty. Complex HCRs that account for both short-term and long-term BMSY targets can mitigate the adverse effects of uncertainty. The rebuilding target can be only achieved by compromising yield, especially when uncertainties with natural mortality and recruitment are present. Strategies based on catch quotas are prone to all sources of uncertainty, indicating latent risks in many current management practices.

scholarly journals Leveraging scientific uncertainty in fisheries management for estimating among-assessment variation in overfishing limits

2019 ◽  
Vol 77 (2) ◽  
pp. 515-526
Author(s):  
Kristin M Privitera-Johnson ◽  
André E Punt
Keyword(s):  
Fisheries Management ◽  
Previous Analysis ◽  
Risk Tolerance ◽  
Scientific Uncertainty ◽  
New Approach ◽  
Control Rules ◽  
Stock Recruitment ◽  
Us West ◽  
Spawning Biomass ◽  
Harvest Control Rules

Abstract Fisheries management systems can utilize probability-based harvest control rules to incorporate scientific uncertainty and manager risk tolerance when setting catch limits. A precautionary buffer that scales with scientific uncertainty is used to calculate the acceptable biological catch from the overfishing limit (OFL) for US West Coast groundfish and coastal pelagic species. A previous analysis formed the basis for estimating scientific uncertainty as the among-assessment variation in estimates of historical spawning biomass time-series. This “historical biomass” approach may underestimate scientific uncertainty, because the OFL is a function of estimated exploitable biomass and fishing mortality. We developed a new approach that bases the calculation of scientific uncertainty on projected spawning biomass (SSB) and OFLs, accounting for uncertainty in recruitment and among-assessment variation. OFL projections yielded a higher estimate of uncertainty than SSB (0.502 vs. 0.413 for 25-year projections and 0.562 vs. 0.384 for a 1-year projection, assuming a deterministic stock-recruitment relationship). Assuming a stochastic stock-recruitment relationship produced smaller estimates of uncertainty (0.436, 25-year OFL projections; 0.452, 1-year OFL projections; 0.360, 25-year SSB projections; 0.318, 1-year SSB projections). The projection-based approach presented herein is applicable across stocks and regions that conduct assessments with sufficient and consistent outputs for calculating an OFL.

scholarly journals Complex assessments or simple management procedures for efficient fisheries management: a comparative study

2014 ◽  
Vol 72 (1) ◽  
pp. 262-274 ◽  
Author(s):  
H. F. Geromont ◽  
D. S. Butterworth
Keyword(s):  
Fishery Management ◽  
Stock Assessment ◽  
Assessment Methods ◽  
Essential Requirement ◽  
Fish Stocks ◽  
Control Rules ◽  
Management Procedures ◽  
Simple Rules ◽  
Sound Management

Abstract Complex stock assessment methods are data- and expertise-hungry, with the annual updates of catch-at-age data and models typically seen as an essential requirement for sound management. But are the heavy commitments of resources required for this level of annual intervention really necessary to achieve efficient long-term fishery management? This question is addressed through a retrospective analysis of management performance over the last 20 years for four North Atlantic fish stocks. The assessments for two of these stocks have exhibited fairly strong retrospective patterns. The actual assessment advice for these stocks was provided based on complex assessment methods making use of age data. The outcomes are compared with what could have been achieved with much simpler catch control rules based upon age-aggregated survey indices alone. Even for the stocks whose assessments exhibit retrospective patterns, these simple rules can achieve virtually equivalent catch and risk performance, with much less interannual TAC variability, compared with what actually occurred over the past 20 years.

Effects of high pressure on the crystallization of carbon fiber reinforced polyetheretherketone (CF/PEEK) laminate composites

1990 ◽  
Vol 48 (4) ◽  
pp. 876-877
Author(s):  
Hong-Ming Lin ◽  
C. H. Liu ◽  
R. F. Lee
Keyword(s):  
High Pressure ◽  
Carbon Fiber ◽  
Sample Surface ◽  
High Yield ◽  
Fiber Reinforced ◽  
Laminate Composites ◽  
Peek Composite ◽  
Continuous Carbon Fiber ◽  
Carbon Fiber Reinforced

Polyetheretherketone (PEEK) is a crystallizable thermoplastic used as composite matrix materials in application which requires high yield stress, high toughness, long term high temperature service, and resistance to solvent and radiation. There have been several reports on the crystallization behavior of neat PEEK and of CF/PEEK composite. Other reports discussed the effects of crystallization on the mechanical properties of PEEK and CF/PEEK composites. However, these reports were all concerned with the crystallization or melting processes at or close to atmospheric pressure. Thus, the effects of high pressure on the crystallization of CF/PEEK will be examined in this study.The continuous carbon fiber reinforced PEEK (CF/PEEK) laminate composite with 68 wt.% of fibers was obtained from Imperial Chemical Industry (ICI). For the high pressure experiments, HIP was used to keep these samples under 1000, 1500 or 2000 atm. Then the samples were slowly cooled from 420 °C to 60 °C in the cooling rate about 1 - 2 degree per minute to induce high pressure crystallization. After the high pressure treatment, the samples were scanned in regular DSC to study the crystallinity and the melting temperature. Following the regular polishing, etching, and gold coating of the sample surface, the scanning electron microscope (SEM) was used to image the microstructure of the crystals. Also the samples about 25mmx5mmx3mm were prepared for the 3-point bending tests.

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