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 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.

Evolution of a co-management arrangement in Japanese offshore fisheries: current policy and legal framework and a case study of the tiger puffer fishery in Ise–Mikawa Bay

2019 ◽  
Vol 76 (6) ◽  
pp. 1567-1580
Author(s):  
Kanae Tokunaga ◽  
Tsutom Miyata ◽  
Hiroki Wakamatsu
Keyword(s):  
Fisheries Management ◽  
Legal Framework ◽  
Economic Benefits ◽  
Current Policy ◽  
Coastal Fisheries ◽  
Control Rules ◽  
Community Boundaries ◽  
Tiger Puffer ◽  
Harvest Control Rules

Abstract This study examines Japanese offshore fisheries management by focusing on the possibilities and challenges in implementing co-management of fisheries. Offshore fisheries, characterized by a lack of clear geographical boundaries in fishing grounds and community boundaries in fishery participants, face different challenges than coastal fisheries that are managed by territorial use rights and fisheries cooperative associations. This study examines the current policy and legal framework in offshore fisheries management in Japan and uses a case study of the tiger puffer fishery in Ise–Mikawa Bay to investigate interactions among multiple fishing entities as well as interactions between resource harvesters and managers. We argue that increased participation of both national and prefectural governments in fisheries management contributes to strengthen co-management: yet, a lack of science-based harvest control rules hinders the biological and economic benefits from accruing to the fishery.

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.

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 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 Performance of harvest control rules in a variable environment

2010 ◽  
Vol 67 (5) ◽  
pp. 1051-1062 ◽  
Author(s):  
Thomas Brunel ◽  
Gerjan J. Piet ◽  
Ralf van Hal ◽  
Christine Röckmann
Keyword(s):  
Dynamic Models ◽  
Generalized Additive Models ◽  
Maximum Sustainable Yield ◽  
Additive Models ◽  
Precautionary Approach ◽  
Variable Environment ◽  
Control Rules ◽  
Stock Biomass ◽  
Stock Recruitment ◽  
Harvest Control Rules

AbstractBrunel, T., Piet, G. J., van Hal, R., and Röckmann, C. 2010. Performance of harvest control rules in a variable environment. – ICES Journal of Marine Science, 67: 1051–1062. Population dynamic models used for fisheries management assume that stocks are isolated entities, ignoring the influence of environmental factors on stock productivity. An operating model parameterized for North Sea cod, plaice, and herring is developed, in which the link between recruitment and environment is assumed to be known and described by generalized additive models. This tool is used to compare the performance of harvest control rules (HCRs) when recruitment is independent of the environment or when recruitment is affected by an environment varying according to different scenarios. The first HCR exploited the stock with a fixed fishing mortality (F) corresponding to maximum sustainable yield, and in the second HCR, F was set equal to the precautionary approach F (i.e. Fpa), but reduced from Fpa when stock biomass fell below Bpa. The performance of the HCRs altered only slightly in a randomly varying environment compared with a constant one. For a detrimental change in the environment, however, no HCR could prevent a massive decrease in stock size. The performance of the HCRs was also influenced by the stock characteristics, such as recruitment variability or the shape of the stock–recruitment relationship. The performance of “environmental” HCRs (eHCRs), in which F varies depending on environmental conditions, was compared with that of conventional HCRs. The gain in using the eHCR was small, except for a detrimental change in the environment, where the eHCR performed markedly better than a conventional HCR. The benefits of using the eHCR were the greatest for the stock with the strongest environment–recruitment relationship.

scholarly journals Harvest control rules in modern fisheries management

Elem Sci Anth ◽  
2016 ◽  
Vol 4 ◽  
pp. 000114 ◽  
Author(s):  
Sturla F. Kvamsdal ◽  
Arne Eide ◽  
Nils-Arne Ekerhovd ◽  
Katja Enberg ◽  
Asta Gudmundsdottir ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Control Rules ◽  
Harvest Control Rules

An Alternative Perspective on Recruitment Overfishing and Biological Reference Points

1987 ◽  
Vol 44 (4) ◽  
pp. 913-918 ◽  
Author(s):  
M. P. Sissenwine ◽  
J. G. Shepherd
Keyword(s):  
Fisheries Management ◽  
Reference Point ◽  
Reference Points ◽  
Fishing Mortality ◽  
Alternative Perspective ◽  
Conventional Models ◽  
Definition Of ◽  
Yield Per Recruit ◽  
Spawning Biomass

Biological reference points are used to guide fisheries management decisions. The reference points most often used are expressed in terms of fishing mortality rate (F). Fmsy relates to the maximization of sustainable yield. In principle, it is a most useful reference point, but in practice it is difficult to estimate. Fmax and F0.1 relate to certain levels of yield per recruit and are easily estimated, but they ignore conservation of the resource. Recruitment overfishing has usually been understood to occur when a population has been fished down to a point where recruitment is substantially reduced or fails. It has not been used as a basis for a biological reference point because the definition is vague and cannot be readily related to fishing mortality. Levels of spawning biomass below which recruitment seems to be reduced have been used, but their determination from available data is usually difficult and controversial. We propose an alternative definition of recruitment overfishing in terms of the level of fishing pressure that reduces the spawning biomass of a year class over its lifetime below the spawning biomass of its parents on average. Conventional models and types of data can be used to determine this level of F, denoted as Frep, which clearly relates to the replacement of spawning biomass and thus to sustainability of a population and yield in the long term.

scholarly journals Evaluating deepwater fisheries management strategies using a mixed-fisheries and spatially explicit modelling framework

2013 ◽  
Vol 70 (4) ◽  
pp. 768-781 ◽  
Author(s):  
Paul Marchal ◽  
Youen Vermard
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Spatially Explicit ◽  
Catch Per Unit Effort ◽  
Modelling Framework ◽  
Control Rules ◽  
Bioeconomic Modelling ◽  
Stock Assessments ◽  
Fleet Dynamics

Abstract Marchal, P., and Vermard, Y. 2013. Evaluating deepwater fisheries management strategies using a mixed-fisheries and spatially explicit modelling framework. – ICES Journal of Marine Science, 70: 768–781. We have used in this study a spatially explicit bioeconomic modelling framework to evaluate management strategies, building in both data-rich and data-limited harvest control rules (HCRs), for a mix of deepwater fleets and species, on which information is variable. The main focus was on blue ling (Molva dypterygia). For that species, both data-rich and data-limited HCRs were tested, while catch per unit effort (CPUE) was used either to tune stock assessments, or to directly trigger management action. There were only limited differences between the performances of both HCRs when blue ling biomass was initialized at the current level, but blue ling recovered more quickly with the data-rich HCR when its initial biomass was severely depleted. Both types of HCR lead, on average, to a long-term recovery of both blue ling and saithe (Pollachius virens) stocks, and some increase in overall profit. However, that improvement is not sufficient to guarantee sustainable exploitation with a high probability. Blue ling CPUE did not always adequately reflect trends in biomass, which mainly resulted from fleet dynamics, possibly in combination with density-dependence. The stock dynamics of roundnose grenadier (Coryphaenoides rupestris), black scabbardfish (Aphanopus carbo) and deepwater sharks (Centrophorus squamosus and Centroscymnus coelolepis) were little affected by the type of HCR chosen to manage blue ling.

Comparison of reference points estimated using a size-based method for two high-latitude crab species in the United States and Canada

2004 ◽  
Vol 61 (8) ◽  
pp. 1404-1430 ◽  
Author(s):  
M SM Siddeek ◽  
Bernard Sainte-Marie ◽  
Jim Boutillier ◽  
Gretchen Bishop
Keyword(s):  
United States ◽  
High Latitude ◽  
The United States ◽  
Reference Points ◽  
Minimum Size ◽  
Snow Crab ◽  
Harvest Rate ◽  
Stock Recruitment ◽  
Dungeness Crabs ◽  
Spawning Biomass

We briefly reviewed the decision rules currently used for managing two major high-latitude crab stocks, snow crab (Chionoecetes opilio) and Dungeness crab (Cancer magister), in the United States and Canada and compared them with model-based reference points, harvest rate, and biomass proportion relative to virgin biomass, developed using species- and area-specific parameters. The model followed a size-based approach, which incorporated Beverton–Holt and Ricker stock–recruitment models and estimated mean and median reference points. The recruitment was also perturbed to generate distributions of reference points. The Beverton–Holt stock–recruitment model provided a lower harvest rate than that of the Ricker model. Harvest rates were lower for combined sexes spawning biomass than for female-only spawning biomass. Increasing the minimum size at first capture and decreasing the handling mortality resulted in increased harvest rates. Changes in fishery duration and timing of fishery open date did not change the harvest rate appreciably. The harvest rates for the Canadian snow and Dungeness crabs were mostly higher than those estimated for the Bering Sea and Southeast Alaska stocks. Reliable estimates of a number of life history parameters are lacking for both species, and hence, the results of this exercise need to be treated in a precautionary manner.

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