scholarly journals Improving Fishery Management Models and Methods

2021 ◽  
Vol 14 (2) ◽  
Author(s):  
Ingólfur Arnarson ◽  
Pall Jensson
Keyword(s):  
Fishery Management ◽  
Inductive Reasoning ◽  
Dynamic Environment ◽  
Economic Models ◽  
Economic Consequences ◽  
Inductive Method ◽  
Market Prices ◽  
Relative Prices ◽  
Fish Stocks ◽  
Management Schemes

In a dynamic, environment, the decision makers make use of many different resources where two or more can act as substitutes.  At each decision moment in time, the market prices will be constant, and the relative prices of accessible resources will determine the economic rationale of the process.  Ignoring or downplaying the effects of substitutability of resources in dynamic economic processes may lead to mismanagement of the fish stocks and result in serious economic consequences for the respective fishing industries. For nearly five decades’ fishery managers and policy makers have used bio-economic models and methods as foundation for their management schemes.  These models and methods are for the most based on the deductive methodology of economics where central assumptions are the metaphors of “equilibrium“ and “bio-economic equilibrium“.  Models based on equilibrium theories are usually deterministic where dynamics of the markets are a meager part of the problem.Less attention has been offered to inductive reasoning and modeling within the field of fishery management.  The inductive method of reasoning is often based on facts and actual observations within the industries, a methodology widely used by engineers and the field of business administration.In this paper, we introduce and integrate the concept of substitutability of economic resources into a traditional bio-economic model.    The results show that fishery management, which bases decisions solely on traditional bio-economic models where the dynamics and consequences of the operational decision processes of the industry are ignored, may reach decisions that work opposite of their intention. 

scholarly journals From Safety Net to Point of No Return—Are Small-Scale Inland Fisheries Reaching Their Limits?

2020 ◽  
Vol 12 (18) ◽  
pp. 7299
Author(s):  
Pina Lena Lammers ◽  
Torsten Richter ◽  
Jasmin Mantilla-Contreras
Keyword(s):  
Sustainable Management ◽  
Fishery Management ◽  
Safety Net ◽  
Small Scale ◽  
Current Function ◽  
Fish Stocks ◽  
Inland Fisheries ◽  
Point Of No Return ◽  
Agricultural Yields ◽  
Near Future

Small-scale inland fisheries (SSIF) are a livelihood opportunity for millions of people in developing countries. Understanding the economic, ecological, political and social impacts fishers are coping with can clarify weaknesses and challenges in the fishery management. Using the SSIF at Lake Alaotra, Madagascar, as an example, we analyzed the development and fishers’ perception of, and adaptation strategies to, change. We surveyed fish catches to assess the state of fish stocks and conducted interviews to understand fishers’ livelihood, problems, behavior and attitudes. Our results show that the fishery sector of Lake Alaotra has grown dramatically although fish catches have fallen sharply. Changes in species composition and low reproduction rates reflect the fishing pressure. A point of no return seems near, as decreasing agricultural yields force farmers to enter the fishery sector as a form of livelihood diversification. Lake Alaotra reflects an alarming trend which can already be seen in many regions of the world and may affect a growing number in the near future. The Alaotran fisheries demonstrate that SSIF’s ability to provide livelihood alternatives under conditions of insecurity will become increasingly important. It further highlights that the identification of ongoing livelihood dynamics in order to disclose possible poverty trap mechanisms and to understand fisheries’ current function is essential for sustainable management.

scholarly journals Flawed evidence supporting the Metabolic Theory of Ecology may undermine goals of ecosystem-based fishery management: the case of invasive Indo-Pacific lionfish in the western Atlantic

2016 ◽  
Vol 74 (5) ◽  
pp. 1256-1267
Author(s):  
Diego Valderrama ◽  
KathrynAnn H. Fields
Keyword(s):  
Fishery Management ◽  
Environmental Temperature ◽  
Growth Parameters ◽  
Fish Mortality ◽  
Natural Mortality ◽  
Metabolic Theory ◽  
Prey Fish ◽  
Western Atlantic ◽  
Fish Stocks ◽  
Metabolic Theory Of Ecology

Given its ability to yield predictions for very diverse phenomena based only on two parameters—body size and temperature—the Metabolic Theory of Ecology (MTE) has earned a prominent place among ecology’s efficient theories. In a seminal article, the leading proponents of the MTE claimed that the theory was supported by evidence from Pauly’s (On the interrelationships between natural mortality, growth parameters, and mean environmental temperature in 175 fish stocks. Journal Du Conseil International Pour L’Exploration de la mer 39:175–192) dataset on natural mortality, biomass, and environmental temperature for 175 fish stocks spanning tropical, temperate, and polar locations. We demonstrate that the evidence presented by the proponents of the MTE is flawed because it fails to account for the fact that Pauly re-estimated environmental temperatures for polar fish as ‘physiologically effective temperatures’ to correct for their ‘abnormally’ high natural (mass-corrected) mortalities, which on average turned out to be similar to (rather than lower than) the mortalities recorded for temperate fish. Failing to account for these modifications skews the coefficients from MTE regression models and wrongly validates predictions from the theory. It is important to point out these deficiencies given the broad appeal of the MTE as a theoretical framework for applied ecological research. In a recent application, the MTE was used to estimate biomass production rates of prey fish in a model of invasive Indo-Pacific lionfish (Pterois volitans and P. miles) predation in Bahamian reefs. We show that the MTE coefficients may lead to a drastic overestimation of prey fish mortality and productivity rates, leading to erroneous estimations of target densities for ecological control of lionfish stocks. A set of robust mortality-weight coefficients is proposed as an alternative to the MTE.

scholarly journals Bioeconomic model of spatial fishery management in developing countries

2012 ◽  
Vol 17 (2) ◽  
pp. 145-161 ◽  
Author(s):  
Wisdom Akpalu ◽  
Godwin K. Vondolia
Keyword(s):  
Developing Countries ◽  
Fishery Management ◽  
Marine Reserve ◽  
Social Planner ◽  
Bioeconomic Model ◽  
Ad Valorem Tax ◽  
Fish Stocks ◽  
Using Data ◽  
Spatial Externality ◽  
Distant Water Fishing

AbstractFishers in developing countries do not have the resources to acquire advanced technologies to exploit offshore fish stocks. As a result, the United Nations Convention on the Law of the Sea requires countries to sign partnership agreements with distant water fishing nations to exploit offshore stocks. However, for migratory stocks, the offshore may serve as a natural marine reserve (i.e., a source) to the inshore (i.e., sink); hence these partnership agreements generate a spatial externality. In this paper, we present a bioeconomic model in which a social planner uses a landing tax (ad valorem tax) to internalize this spatial externality. We found that the tax must reflect the biological connectivity between the two patches, intrinsic growth rate, the price of fish and cost per unit effort. The results are empirically illustrated using data on Ghana.

Marking-to-Market, Commonality in Liquidity, and Government Guarantee Effect

2016 ◽  
Vol 32 (1) ◽  
pp. 73-91
Author(s):  
Hawfeng Shyu
Keyword(s):  
Financial Crisis ◽  
Positive Association ◽  
Fair Value ◽  
Market Liquidity ◽  
Economic Consequences ◽  
Vicious Cycle ◽  
Market Prices ◽  
Stock Liquidity ◽  
Government Guarantee ◽  
Value Measurement

Based on market prices and other market inputs to value assets and liabilities, adopting fair-value measurement creates many unpredictable economic consequences, such as amplifying the vicious cycle of falling prices during a worldwide financial crisis. This article investigates whether marking-to-market disclosure affects the commonality in liquidity. Commonality in liquidity is defined as the sensitivity of stock liquidity to the variation in market liquidity. My study indicates that marking-to-market disclosure is associated with higher commonality in liquidity. In addition, I find that higher commonality in liquidity is associated with lower stock liquidity. I also find that a positive association between commonality in liquidity and stock illiquidity is mitigated by the effect of a government guarantee.

Bio-Socio-Economic Fishery Models: Labour Dynamics and Multi-Objective Management

1989 ◽  
Vol 46 (8) ◽  
pp. 1313-1322 ◽  
Author(s):  
Anthony T. Charles
Keyword(s):  
Fishery Management ◽  
Economic Modelling ◽  
Fish Stocks ◽  
Multi Objective ◽  
Net Migration ◽  
Complex Interactions ◽  
The People ◽  
Joint Dynamics ◽  
Employment Rates ◽  
External Economy

Fishery systems involve complex interactions between resource stocks and the people involved in harvesting those stocks. While the population dynamics of fish stocks have received considerable attention in the ecological literature, the dynamics of human communities dependent on the fishery are equally important. Indeed the joint dynamics of the fish stocks and the fishermen must be taken into account in determining appropriate management policies. A bio-socio-economic modelling approach is developed here to incorporate these effects within a multi-objective optimization framework. Fishery labour dynamics are determined by the decisions of individual fishermen with net migration into and out of the fishery (and hence the fishing community) dependent on internal conditions such as per capita incomes and employment rates, as well as on the state of the external economy. The task of fishery management is then one of balancing multiple objectives – such as conservation, income generation, employment, and community stability – subject to fish and fishermen dynamics. Control theory and simulation methods are used to study the bio-socio-economic dynamics of the fishery system and the interactions of multiple management are also discussed.

Voluntary management in an inshore fishery has conservation benefits

2002 ◽  
Vol 29 (4) ◽  
pp. 493-508 ◽  
Author(s):  
Robert E. Blyth ◽  
Michel J. Kaiser ◽  
Gareth Edwards-Jones ◽  
Paul J.B. Hart
Keyword(s):  
Fishery Management ◽  
Regulatory Compliance ◽  
Management Approach ◽  
Benthic Habitat ◽  
Top Down ◽  
Fish Stocks ◽  
Personal Benefit ◽  
Management Regime ◽  
High Level ◽  
And Function

The management of fisheries in European Union (EU) waters has generally been regulated through government institutions and agreed quota allocations. This top-down management approach may have contributed to the continued decline of targeted fish stocks by forcing fishers to compete for limited resources without engendering a sense of resource stewardship. In attempting to reverse this decline, scientists and managers should examine management systems that do not solely depend on top-down approaches, and the Inshore Potting Agreement (IPA) is an example. The IPA is a voluntary fishery management system designed and operated by inshore fishers of south Devon, England. The IPA was conceived to reduce conflict between static-gear (pot and net) and towed-gear (trawl and dredge) fishers, and is regarded as a successful fisheries management regime by fishers and managers because it has effectively allowed fishers from both sectors to operate profitably on traditional fishing grounds. Another study determined that the IPA has incidentally protected benthic habitat complexity. Fishers from the static-gear and towed-gear sectors were interviewed to determine the evolution and function of the IPA, and to establish the factors that ensure the high level of regulatory compliance amongst fishers from both sectors. Towed-gear fishers gave significantly different responses to the same questions asked of static-gear fishers, and were generally less satisfied with the existence of the IPA. Multivariate analyses of the interview data suggested that fishers who thought the IPA was a good system also thought the system provided pot protection, but had experienced inter-sector conflict. Fishers who thought the IPA provided no personal benefit also thought that static-gear fishers should be more restricted, and that towed-gear corridors or more seasonal-use areas should be established within the existing IPA area. However, fishers from both sectors agreed that the IPA has maintained traditional practices of the local fishing industry, and that the system has conserved target finfish and scallop species. A number of factors were identified as critical to the success of the IPA. These included the voluntary nature of the agreement, the limited number of organizations representing fishers and very high level of membership of those organizations, and the simplicity of the system. Regulatory compliance is enhanced through the ability of fishers' organizations to respond rapidly to inter-sector conflict issues.

A Note on Relative Prices and Income Distribution over the US Business Cycle: 1857–2009

2020 ◽  
pp. 048661342096286
Author(s):  
Claudio Alberto Castelo Branco Puty
Keyword(s):  
Income Distribution ◽  
Business Cycles ◽  
Labor Costs ◽  
Market Prices ◽  
Relative Prices ◽  
Industrial Economy ◽  
Us Economy ◽  
The Us ◽  
Unit Labor Costs ◽  
Jel Classifications

This paper investigates the relation between relative prices and the income distribution by examining variations in output and prices occurred over thirty-three US business cycles from 1857 to 2009. Using a broad database, the author shows that average relative prices in twenty-seven industries of the US economy presented a remarkably smaller variation than the corresponding variation in output levels, profits and wages. These time-series results, although not conclusive, may provide additional empirical evidence of the Ricardian claim that even relative market prices in an industrial economy are strongly dominated by the correspondent integrated unit labor costs and that changes along a wage-profit schedule will play only a secondary role in their determination. JEL classifications: E11, E32

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