Managing fish stocks under climate uncertainty

2005 ◽  
Vol 62 (7) ◽  
pp. 1531-1541 ◽  
Author(s):  
Brian J. Rothschild ◽  
Changsheng Chen ◽  
R. Greg Lough
Keyword(s):  
Decision Theory ◽  
Fishery Management ◽  
Causal Chain ◽  
The State ◽  
Population Characteristics ◽  
Fish Stock ◽  
Fish Stocks ◽  
Formal Framework ◽  
Past Data ◽  
State Of The Environment

Abstract The quantitative evaluation of the management of fish stocks under uncertainty requires a formal framework. Decision theory provides that framework. Application of decision theory to fishery management requires information about both the fish stock and the state of the environment. Using Georges Bank haddock as a case study, it is possible to determine the probability of good or poor recruitment using past data and a constant environment. Understanding the state of the environment is more difficult, however, because fixed levels of recruitment, in particular, are associated with different population characteristics, which drastically reduce the sample size for any particular recruitment–environment scenario. Decision theory challenges us to improve our capability of predicting the state of nature, and it appears that this can be accomplished best by reducing the length of the causal chain, a goal now made feasible by the availability of high-resolution, high-frequency ocean models.

scholarly journals Accounting and disciplinary methods in fishery management

2021 ◽  
Vol 34 (9) ◽  
pp. 218-249
Author(s):  
Stefania Servalli ◽  
Antonio Gitto
Keyword(s):  
Fishery Management ◽  
18Th Century ◽  
The State ◽  
Fish Stock ◽  
Control Mechanisms ◽  
Local Authorities ◽  
Local Conditions ◽  
Content Type ◽  
Papal States

PurposeThe purpose of this study is to contribute to the research related to “the interplay between accounting and the state, politics, and local authorities in the broad government and administration of food for sustainability of populations” (Sargiacomo et al., 2016). Considering contemporary examples and investigating the genealogy of an 18th-century reform of fishery management (the New Plan), the authors explore the role played by accounting and calculative practices when local authorities intervene using forms of discipline based on control systems that acted on commons (fish), people and space.Design/methodology/approachThis paper is historically grounded on archival research on a fish provisioning case during the 18th century in Ancona, an Italian town on the Adriatic coast. The investigation adopts an approach focussed on the use of disciplinary methods in the terms highlighted by Foucault. This perspective offers a lens capable of revealing the key role of accounting in a period when discipline became “general formulas of domination” (Foucault, 1977) and the Papal States were looking for food provisioning solutions (Foucault, 2007). The study highlights similarities with contemporary fishery management.FindingsThe paper shows that governability of fishery in a commons' logic is not limited by the properties of the good, but rather “it is achieved through the objects and instruments that are deployed to make it possible” (Johnsen, 2014, p. 429). It reveals forms assumed by economic calculation in different eras and their contribution in the art of governing realised by the state (Hoskin and Macve, 2016). The study unveils how accounting effectively operates using “naming and counting” activities (Ezzamel and Hoskin, 2002) based on a system of documents and accounting registers; these have a pivotal role in redefining fishery management and in keeping goods (fish) and people (fishermen) under control. The investigation also highlights the importance of properly quantifying data in fishery management, confirming the literature on the topic (Beddington et al., 2007, p. 1713). In contemporary situations, data refer to quantifying the fish stock in the sea and the consequent estimation of fish catch. In the historical investigation, although environmental protection was not an issue, quantification refers to the fish that entered the town of Ancona, whose estimation was the result of a new calculative approach adopted by local authorities facing fish needs. In addition, it offers early evidence of organised and rational-based control mechanisms that were the result of Enlightened ideas emerging in the Papal States context.Originality/valueDespite the fact that fish represent a fundamental good for governments to act on in response to a population's needs, there has been no attention paid to how governmental authorities have used disciplinary mechanisms to intervene in fishery management or the role played by accounting. This study's novelty is its investigation of fishery, using Foucauldian disciplinary methods to understand accounting's contribution in fishery governance. In addition, this investigation permits to unveil the role of accounting to support one of the main principles of the governance of commons that is represented by the congruence between rules and local conditions (Fennell, 2011, p. 11; Ostrom, 1990, p. 92).

scholarly journals When is a fish stock collapsed?

2018 ◽  
Author(s):  
J Yletyinen ◽  
WE Butler ◽  
G Ottersen ◽  
KH Andersen ◽  
S Bonanomi ◽  
...  
Keyword(s):  
Life Histories ◽  
The State ◽  
Systematic Evaluation ◽  
Occurrence Rate ◽  
Fish Stock ◽  
Policy Makers ◽  
Fish Stocks ◽  
The Public ◽  
Population Turnover

AbstractMarine fish stock collapses are a major concern for scientists and society due to the potentially severe impacts on ecosystem resilience, food security and livelihoods. Yet the general state of harvested fish populations has proven difficult to summarize, and the actual occurrence rate of stock collapses remains unclear. We have carried out a literature review and multi-stock analysis to show that numerous definitions exist for classifying stocks as collapsed, and that the classification of a stock’s status is sensitive to changes in the collapse definition’s formulation. We suggest that the lack of a unified definition has contributed to contrasting perceptions on the state of fish stocks. Therefore, we comprehensively define what constitutes a fish stock collapse and provide a time-series based method for collapse detection. Unlike existing definitions, our definition is process-based, because it links together three important phases of collapse events: the abrupt decline, an ensuing period of prolonged depletion, and potential recovery. Furthermore, these phases are specified in terms of population turnover. Through systematic evaluation, our definition can accurately distinguish collapses from less severe depletions or natural fluctuations for stocks with diverse life histories, helping identify the stocks in greatest need of reparatory measures. Our study advocates the consistent use of definitions to limit both alarmist and conservative narratives on the state of fish stocks, and to promote cooperation between conservation and fisheries scientists. This will facilitate clear and accurate communication of science to both the public and to policy-makers to ensure healthy fish stocks in the future.

scholarly journals The Importance of Involving Stakeholders and Scientists in the Management of Marine Fisheries

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Anthony D. Hawkins
Keyword(s):  
Fisheries Management ◽  
The State ◽  
Expert Advice ◽  
Fish Stock ◽  
Government Agencies ◽  
Aquatic Environments ◽  
Fish Stocks ◽  
Stock Assessments ◽  
Set Up ◽  
European Regional

In recent years there has been increasing concern over the state of fish stocks, especially those that support key fisheries and supply food to many consumers. There is also concern over the state of aquatic environments, and the effects of climate change. Fisheries management is controlled by government agencies, often cooperating with similar agencies from other nations. This paper deals with the need for expert advice on fisheries, involving fishers as well as scientists. Mention is made of a Fisheries Partnership set up in Europe, bringing fishers and scientists together with other stakeholders to discuss the problems of managing fish stocks. The partnership was especially successful in improving relationships between fishers and scientists, and made significant improvements to some fish stock assessments. European Regional Advisory Councils were later established to play a similar role. They are providing significant advice on fisheries, but they do not yet play a key role in actual management. It is important to consider how stakeholders and scientists can become more actively involved in fisheries management. There is a crucial need to develop new, more participatory ways of managing fisheries.

Innovations in Fishing Gear Design Aiming at the Sustainable Use of Commercial Fish Stocks

2006 ◽  
Author(s):  
Erdmann Dahm
Keyword(s):  
Fishery Management ◽  
Sustainable Use ◽  
Mesh Size ◽  
Fish Stock ◽  
Fishing Gear ◽  
Commercial Fish ◽  
Fish Stocks ◽  
Gear Design ◽  
Ecological Changes ◽  
Open Shape

The present status of some of the fish stocks in North Sea and Baltic shows them to be outside safe biological limits. Reasons for this lie partly in hydrographic and ecological changes not in favour for a constant supply of fresh recruits to the fishery every year. On the other hand, fishery has its share in the observed downward trend by growth overfishing and reducing the size and number of possible spawners. The only mean available for the fishery management to restore a fish stock composed of several year classes is to apply technical measures as e.g.closures in space and time or fishing gear regulations. The breakdown of the historical measure “mesh size regulation in diamond mesh trawls” due to technological progress has created a wave of worldwide research. It has focused on trawl codends where the meshes are held artificially in their most open shape or by introducing into the trawl metal structures able to separate small from big fish or fish from crayfish. A parallel development of a scientifically objective mesh measuring instrument will help to enforce the new regulations. However, longer use of some of the new designs has revealed some deficiencies. Other innovative designs or the concept of certified codends will hopefully ensure the permanently better selectivity of contemporary trawl codends.

Use and abuse of fishery models

2001 ◽  
Vol 58 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Jon T Schnute ◽  
Laura J Richards
Keyword(s):  
World Literature ◽  
Fishery Management ◽  
Stock Assessment ◽  
Management Practice ◽  
Fish Stock ◽  
Fish Stocks ◽  
Creative Thought ◽  
Modeling Process ◽  
Stock Biomass ◽  
Fish Stock Assessment

Recent failures of important fish stocks give mathematical models a poor reputation as tools for fishery management. This paper examines the role of models in fish stock assessment and identifies reasons why they can fail. Starting with laws of arithmetic, models attempt to relate observed data to unknown quantities, such as the stock biomass and abundance. Typically, the number of unknowns greatly exceeds the number of observations, and models must impose hypothetical constraints to give useful estimates. We use the word "fishmetic" (rhymes with arithmetic) to represent uncertainty in the conversion of arithmetic to practical fishery models. Arbitrary assumptions cannot be avoided, even though different choices can greatly influence the outcome of the analysis. We compare the modeling process in fisheries with that in other sciences. World literature also offers useful analogies. Potential reasons for failure suggest possible improvements to the application of fishery models. We recommend that modelers remain skeptical, expand their knowledge base, apply common sense, and implement robust strategies for fishery management. Particularly creative thought must be applied to the problem of translating scientific knowledge into management practice. Comparisons between fish stocks and financial stocks illustrate some possibilities.

scholarly journals The Importance of Involving Stakeholders and Scientists in the Management of Marine Fisheries

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Anthony D. Hawkins
Keyword(s):  
Fisheries Management ◽  
The State ◽  
Expert Advice ◽  
Fish Stock ◽  
Government Agencies ◽  
Aquatic Environments ◽  
Fish Stocks ◽  
Stock Assessments ◽  
Set Up ◽  
European Regional

In recent years there has been increasing concern over the state of fish stocks, especially those that support key fisheries and supply food to many consumers. There is also concern over the state of aquatic environments, and the effects of climate change. Fisheries management is controlled by government agencies, often cooperating with similar agencies from other nations. This paper deals with the need for expert advice on fisheries, involving fishers as well as scientists. Mention is made of a Fisheries Partnership set up in Europe, bringing fishers and scientists together with other stakeholders to discuss the problems of managing fish stocks. The partnership was especially successful in improving relationships between fishers and scientists, and made significant improvements to some fish stock assessments. European Regional Advisory Councils were later established to play a similar role. They are providing significant advice on fisheries, but they do not yet play a key role in actual management. It is important to consider how stakeholders and scientists can become more actively involved in fisheries management. There is a crucial need to develop new, more participatory ways of managing fisheries.

Long-term changes in fish pond management as ‘an unplanned ecosystem experiment’: importance of zooplankton structure, nutrients and light for species composition of cyanobacterial blooms

1995 ◽  
Vol 32 (4) ◽  
pp. 187-196 ◽  
Author(s):  
L. Pechar
Keyword(s):  
Species Composition ◽  
Fishery Management ◽  
Grazing Pressure ◽  
Organic Fertilizers ◽  
Cyanobacterial Blooms ◽  
Fish Stock ◽  
Fish Ponds ◽  
Single Filament ◽  
The 1950S ◽  
Water Blooms

The study presents data on the species composition of cyanobacterial water blooms in Czech fish ponds from the 1950s to the 1990s. Since the 1950s, a shift from large-colonial Aphanizomenon flos-aquae var. flos-aquae through Microcystis aeruginosa and small-colonial species of Anabaena to single-filament species (Planktohrix agardhii, Limnothrix redekei, Aphanizomenon gracile) or single-cell forms (Microcystis ichtyoblabe), has been observed. The changes in the species composition of the water blooms are closely related to changes in fishery management (increase in fish stock, increase in application of organic fertilizers). At present the high predation of fish upon zooplankton results in elimination of large colonial blooms of A. flos-aquae associated with large filtering zooplankton (Daphnia). Low grazing pressure of zooplankton, low light conditions and low N:P ratios are suitable conditions for mass development of the small species of cyanobacteria. High pH is not necessary to achieve cyanobacteria dominance.

scholarly journals Bayesian natural selection and the evolution of perceptual systems

2002 ◽  
Vol 357 (1420) ◽  
pp. 419-448 ◽  
Author(s):  
Wilson S. Geisler ◽  
Randy L. Diehl
Keyword(s):  
Natural Selection ◽  
Decision Theory ◽  
Ideal Observer ◽  
Statistical Decision Theory ◽  
Statistical Decision ◽  
Natural Stimuli ◽  
Ideal Observers ◽  
Formal Framework ◽  
Bayesian Statistical Decision Theory ◽  
Perceptual Systems

In recent years, there has been much interest in characterizing statistical properties of natural stimuli in order to better understand the design of perceptual systems. A fruitful approach has been to compare the processing of natural stimuli in real perceptual systems with that of ideal observers derived within the framework of Bayesian statistical decision theory. While this form of optimization theory has provided a deeper understanding of the information contained in natural stimuli as well as of the computational principles employed in perceptual systems, it does not directly consider the process of natural selection, which is ultimately responsible for design. Here we propose a formal framework for analysing how the statistics of natural stimuli and the process of natural selection interact to determine the design of perceptual systems. The framework consists of two complementary components. The first is a maximum fitness ideal observer, a standard Bayesian ideal observer with a utility function appropriate for natural selection. The second component is a formal version of natural selection based upon Bayesian statistical decision theory. Maximum fitness ideal observers and Bayesian natural selection are demonstrated in several examples. We suggest that the Bayesian approach is appropriate not only for the study of perceptual systems but also for the study of many other systems in biology.

Are listed threatened plant species actually at risk?

2002 ◽  
Vol 50 (1) ◽  
pp. 1 ◽  
Author(s):  
Mark A. Burgman
Keyword(s):  
Plant Species ◽  
Threatened Species ◽  
Feedback Loop ◽  
Conservation Status ◽  
The State ◽  
Scarce Resources ◽  
Threatened Plant ◽  
Threatened Plant Species ◽  
Legal Mandates ◽  
State Of The Environment

Despite the fact that the most changes in lists of threatened species reflect changes in knowledge rather than changes in conservation status, the lists continue to provide social and legal mandates for conservation; they are used to report on the state of the environment and to guide the allocation of scarce resources. There is a substantial under-representation of non-vascular species in threatened plant lists, reflected in an absence of documented extinctions among fungi and algae. Turnover in the composition of extinct flora lists in Australia suggests that the lists of threatened species may not be sufficiently reliable to form the basis for reporting on the state of the environment. They are of limited use in distinguishing between levels of threat and may not be a reliable guide for the allocation of scarce conservation resources among plant species. Systems for listing threatened species create a feedback loop, responsive to the subjective preferences of scientists, largely unresponsive to underlying true threats, self-perpetuating and accentuating bias with each iteration. Other tools, including formal decision approaches and the acquisition of new kinds of data, are needed to fill the roles.

A Synthesis of Knowns, Unknowns, and Policy Recommendations from the Sea Lamprey International Symposium

1980 ◽  
Vol 37 (11) ◽  
pp. 2202-2208 ◽  
Author(s):  
Carl J. Walters ◽  
George Spangler ◽  
W. J. Christie ◽  
Patrick J. Manion ◽  
James F. Kitchell
Keyword(s):  
International Symposium ◽  
Large Scale ◽  
Fishery Management ◽  
Field Experiments ◽  
Lake Trout ◽  
Sea Lamprey ◽  
Future Research ◽  
Fish Stock ◽  
Total Production ◽  
Pilot Studies

The Sea Lamprey International Symposium (SLIS) has provided a broad spectrum of facts and speculations for consideration in future research and management programs. Many aspects of the laboratory biology and field life history of the sea lamprey (Petromyzon marinus) are now well understood. There is little question that it can now be controlled by chemical larvicides, and perhaps in the future by more efficient integrated control programs. There is correlative evidence (wounds, scars, catch curves) that lamprey caused major mortalities in some fish species, and that control in conjunction with stocking has lead to remarkable recoveries of salmonid stocks in the Great Lakes. However, there are great gaps in understanding about just what the lamprey does under field conditions, and it is not yet possible to reject several hypotheses that assign lamprey a minimum or transient role in fish stock changes. Further studies on details of lamprey biology are, in themselves, unlikely to fill the gaps; one alternative is to conduct a large-scale field experiment involving cessation of lamprey control while holding other factors (fishing, stocking) as steady as possible. If it is decided to proceed with management on the assumption that lamprey are important, without the major field experiments to confirm it, then at least the following steps should be taken: (1) the chemical treatment program should be reviewed in detail, with a view to finding treatment schedules that will minimize frequency and dose rates for lampricide applications; (2) pilot studies on alternative control schemes (sterile male, attractants, barriers) should only be funded if they are statistically well designed (several replicate and control streams), and involve quantitative monitoring of lamprey spawning success and subsequent total production of transforming larvae; (3) the lake trout (Salvelinus namaycush) stocking program should be maintained at its present level, and should involve diverse genotypes rather than a few hatchery strains; (4) growth in the sport fisheries for lake trout should be curtailed, and commercial fisheries should not yet be permitted; (5) a multispecies harvesting policy should be designed that takes into account the buffering effect of each species on lamprey mortality suffered by others (i.e. should some species not be harvested at all, and viewed instead as buffers for more valuable species?); and (6) a program should be developed for restoring, by culture if necessary, native forage species in case the introduced smelt and alewife should collapse under pressure from fishing and prédation by the growing salmonid community.Key words: sea lamprey, proposed research, fishery management, mathematical models, population dynamics

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