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 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.

scholarly journals An alternative reference point in the context of ecosystem-based fisheries management: maximum sustainable dead biomass

2015 ◽  
Vol 72 (8) ◽  
pp. 2257-2268 ◽  
Author(s):  
Hans-Joachim Rätz ◽  
John Casey ◽  
Steven J. Holmes ◽  
Josep Lloret ◽  
Hendrik Dörner ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Reference Points ◽  
Production Model ◽  
Fish Stock ◽  
Compensatory Mechanism ◽  
Fishing Mortality ◽  
Dead Biomass ◽  
Selection Pattern ◽  
Stock Biomass ◽  
Spawning Stock

Abstract Under the 2013 Reform of the European Union's Common Fisheries Policy (CFP), fisheries management aims to ensure that, within a reasonable time frame, the exploitation of marine biological resources restores and maintains populations of harvested stocks above levels that can produce the maximum sustainable yield (MSY). The CFP also calls for the implementation of an ecosystem-based approach to fisheries management (EBFM). In this paper, we present the concept of maximum sustainable dead biomass (MSDB) and its associated management reference points for fishing mortality and spawning-stock biomass as alternatives to those associated with MSY. The concept of MSDB is illustrated by a dynamic pool production model of a virtual fish stock which takes into account variations in natural mortality (M), fishing mortality (F), and exploitation pattern. Our approach implies a compensatory mechanism whereby survivors may benefit from compensatory density dependence and is implemented through progressive substitution of M with F for varying rates of total mortality (Z). We demonstrate that the reference points for fishing mortality and spawning-stock biomass associated with MSDB are less sensitive to increasing compensation of M with F than those associated with MSY and more sensitive to changes in selection pattern. MSDB-based reference points, which are consistent with maximum stock productivity, are also associated with lower fishing mortality rates and higher stock biomasses than their MSY-based counterparts. Given that selection pattern can be influenced through fishery input measures (e.g. technical gear measures, decisions on areas, and/or times of fishing), whereas variations of M in response to F are not controllable (indeed poorly understood), that the results of many fish stock assessments are imprecise, that maximum stock productivity corresponds to MSDB and that MSY-based reference points may best be considered as limits, we propose that MSDB-based reference points provide a more appropriate basis for management under an EBFM.

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 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 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.

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 Ecosystem-based reference points under varying plankton productivity states and fisheries management strategies

2019 ◽  
Vol 76 (7) ◽  
pp. 2045-2059 ◽  
Author(s):  
Chuanbo Guo ◽  
Caihong Fu ◽  
Robyn E Forrest ◽  
Norm Olsen ◽  
Huizhu Liu ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Reference Points ◽  
Productivity Change ◽  
Pacific Herring ◽  
Fishing Mortality ◽  
Pacific Cod ◽  
Sustainable Fisheries ◽  
Ecosystem Effects ◽  
Plankton Biomass

Abstract In the context of ecosystem-based fisheries management, which should consider changing and uncertain environmental conditions, the development of ecosystem-based biological reference points (EBRPs) to account for important multi-species (MS) interactions, fishery operations, and climate change, is of paramount importance for sustainable fisheries management. However, EBRPs under varying plankton productivity states and fisheries management strategies are seldom developed, and the ecosystem effects of these changes are still largely unknown. In this study, ecosystem-based FMSY (fishing mortality rate at MSY) values were estimated within an end-to-end ecosystem model (OSMOSE) for three focused fish species (Pacific Herring, Clupea pallasii; Pacific Cod, Gadus macrocephalus; Lingcod, Ophiodon elongatus) under three plankton productivity states of differing plankton biomass at high, current, and low levels. In addition, ecosystem effects were compared across different plankton productivity and fisheries management strategies with the latter consisting of two fishery scenarios (i.e. single-species-focused (SS) and MS-focused), various fishing mortality rates, and two harvest policies (with and without harvest control rules, HCRs). Main findings of this study include: (i) plankton productivity change affected the values of ecosystem-based FMSY, which increased as plankton productivity states changed from low to high plankton biomass; (ii) ecosystem-based FMSY for Pacific Herring and Pacific Cod stocks increased when fishery scenarios shifted from SS-focused to MS-focused; (iii) fisheries management incorporating HCR yielded more stable system catch and system biomass; and (iv) high plankton biomass combined with fisheries management using HCR could maintain stable ecosystem production and sustainable fisheries. Based on our findings, we highlight possible adaptive fisheries management strategies in the face of future climate and ocean changes. Overall, EBRPs complement SS stock assessments by incorporating key ecological processes and ecosystem properties, thus providing supporting evidence for better incorporation of ecosystem considerations into scientific advice for sustainable fisheries management.

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.

CCAMLR’s precautionary approach to management focusing on Ross Sea toothfish fishery

2015 ◽  
Vol 27 (4) ◽  
pp. 333-340 ◽  
Author(s):  
Stuart Hanchet ◽  
Keith Sainsbury ◽  
Doug Butterworth ◽  
Chris Darby ◽  
Viacheslav Bizikov ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Management System ◽  
Ross Sea ◽  
Stock Assessment ◽  
Precautionary Approach ◽  
Adaptive Feedback ◽  
Stock Biomass ◽  
Stock Assessments ◽  
Antarctic Marine ◽  
Spawning Stock

AbstractSeveral recent papers have criticized the scientific robustness of the fisheries management system used by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), including that for Ross Sea toothfish. Here we present a response from the wider CCAMLR community to address concerns and to correct some apparent misconceptions about how CCAMLR acts to promote conservation whilst allowing safe exploitation in all of its fisheries. A key aspect of CCAMLR’s approach is its adaptive feedback nature; regular monitoring and analysis allows for adjustments to be made, as necessary, to provide a robust management system despite the statistical uncertainties inherent in any single assessment. Within the Ross Sea, application of CCAMLR’s precautionary approach has allowed the toothfish fishery to develop in a steady fashion with an associated accumulation of data and greater scientific understanding. Regular stock assessments of the fishery have been carried out since 2005, and the 2013 stock assessment estimated current spawning stock biomass to be at 75% of the pre-exploitation level. There will always be additional uncertainties which need to be addressed, but where information is lacking the CCAMLR approach to management ensures exploitation rates are at a level commensurate with a precautionary approach.

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.

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