Monitoring artisanal hilsa fishery for economic efficient fisheries policy

The hilsa shad (Tenualosa ilisha) fishery contributes to the largest single species fishery in Bangladesh. In this paper, a simple bio-economic year-class based model was developed from 1987 & 2007 fishing data to describe the fishery and examine its properties. With the help of this model, the optimum sustainable yield of the fishery was calculated and compared to the existing situation. The model was further used to locate socially and economically reasonable dynamic paths from the current situation to the optimal state. The results indicate that the fishing effort (measured in standardized boat units) required maintaining a maximum sustainable economic benefit is about one-third of the current fishing effort. At this sustainable fishing effort level, annual net economic benefits from the fishery amounted for closed to US$ 260 million compared to virtually nothing at present. The present value of the fishery along a moderate effort adjustment path to this long term equilibrium position was US$ 3,650 million at 6% rate of discount. The dynamic path that maximized the present value of the fishery involved quite dramatic effort reductions for the first two years. Such a path would probably increase the present value of the fishery by perhaps 8-10%.Bangladesh J. Zool. 43(1): 37-53, 2015

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Optimal fishing mortality assignment for southern hake Merluccius australis in Chile

Latin American Journal of Aquatic Research ◽

10.3856/vol48-issue4-fulltext-2283 ◽

2020 ◽

Vol 48 (4) ◽

pp. 613-625

Author(s):

Felipe Lopez ◽

Jorge Jimenez ◽

Cristian Canales

Keyword(s):

Mortality Rate ◽

Economic Benefit ◽

Mortality Rates ◽

Fish Population ◽

Fishing Effort ◽

Economic Benefits ◽

Historical Background ◽

Total Catch ◽

Fishing Mortality ◽

Objective Functions

Since 1979, southern hake (Merluccius australis) has been exploited in Chile from the Bio Bio to the Magallanes regions, between the parallels 41°28.6'S and 57°S. There is evidence of a constant fishing effort and a sustained reduction of the fish population, consistent with a progressive decrease in total annual catches. Management strategies based on the maximum sustainable yield (MSY) and quota assignment/ distribution criteria have not been able to sustain acceptable biomass levels. A non-linear optimization model with two objective functions was proposed to determine an optimal total catch quota for more sustainable exploitation of this fishery. The first function maximizes the total catch over time in response to an optimal assignment of fishing mortality rates per fleet; the second function maximizes the total economic benefit associated with the total catch. The dynamics of the fish population were represented with the equations of a predictive age-structured model. Decision variables were fishing mortality rates and annual catch quotas per fleet, subject to constraints that guarantee a minimum level of biomass escape over a long-term period. The input parameters were obtained from the last stock evaluation report carried out by the Instituto de Fomento Pesquero (IFOP) of Chile. The historical background data of the fishery and the regulatory framework were relevant aspects of the methodology. Five scenarios were evaluated with the two objective functions, including a base scenario, which considered the referential mortality rate as input data as the average mortality rate per fleet from 2007 to 2012. Total economic benefits fluctuate between 102 and USD 442 million for total catches in the range of 108 to 421 thousand tons, which were obtained from maximizing the economic and biological objective functions. Economic benefit/catch ratios were reduced for scenarios with higher constraints on catch limits, and they were more efficient from a biological point of view. Situations with lighter constraints showed in general higher economic benefits and better performance ratios than those with stronger restrictions. The use of optimization models may provide a useful tool to evaluate the effect of regulations for adequate conservation and economical utilization of a limited resource.

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Integrating Economic dynamics into Ecological Networks: The case of fishery sustainability

10.1101/840314 ◽

2019 ◽

Author(s):

Paul Glaum ◽

Valentin Cocco ◽

Fernanda S. Valdovinos

Keyword(s):

Network Theory ◽

Management Strategies ◽

Single Species ◽

Fishing Effort ◽

Ecological Networks ◽

Ecological Network ◽

Ecological Dynamics ◽

Natural Systems ◽

Insight Into

Summary/AbstractUnderstanding and sustainably managing anthropogenic impact on ecosystems requires studying the integrated economic -ecological dynamics driving coupled human-natural systems. Here, we expand ecological network theory to study fishery sustainability by incorporating economic drivers into food-web models to evaluate the dynamics of thousands of single-species fisheries across hundreds of generated food-webs and two management strategies. Analysis reveals harvesting high population biomass species can initially support fishery persistence, but threatens long term economic and ecological sustainability by indirectly inducing extinction cascades in non-harvested species. This dynamic is exacerbated in open access fisheries where profit driven growth in fishing effort increases perturbation strength. Results demonstrate the unique insight into both ecological dynamics and sustainability garnered from considering economically dynamic fishing effort in the network.One Sentence SummaryIntegrating economic drivers into ecological networks reveal non-linear drivers of sustainability in fisheries.

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Bioeconomic multistock reference points as a tool for overcoming the drawbacks of the landing obligation

ICES Journal of Marine Science ◽

10.1093/icesjms/fsw030 ◽

2016 ◽

Vol 74 (2) ◽

pp. 511-524 ◽

Cited By ~ 18

Author(s):

Dorleta García ◽

Raúl Prellezo ◽

Paz Sampedro ◽

José María Da-Rocha ◽

José Castro ◽

...

Keyword(s):

Economic Performance ◽

Net Present Value ◽

Policy Reform ◽

Maximum Sustainable Yield ◽

Reference Points ◽

Present Value ◽

Fisheries Policy ◽

Fleet Dynamics ◽

The Impact

The landing obligation policy was one of the major innovations introduced in the last Common Fisheries Policy reform in Europe. It is foreseen that the policy will affect the use of fishing opportunities and hence the economic performance of the fleets. The problem with fishing opportunities could be solved if single-stock total allowable catches (TACs) could be achieved simultaneously for all the stocks. In this study, we evaluate the economic impact of the landing obligation policy on the Spanish demersal fleet operating in the Iberian Sea region. To generate TAC advice, we used two sets of maximum sustainable yield (MSY) reference points, the single-stock MSY reference points defined by ICES and a set of multistock reference points calculated simultaneously using a bioeconomic optimization model. We found that the impact of the landing obligation is time and fleet dependent and highly influenced by assumptions about fleet dynamics. At fishery level, multistock reference points mitigate the decrease in the net present value generated by the implementation of the landing obligation. However at fleet level, the effect depends on the fleet itself and the period. To ensure the optimum use of fishing opportunities, the landing obligation should be accompanied by a management system that guarantees consistency between single-stock TACs. In this regard, multistock reference points represent an improvement over those currently in use. However, further investigation is necessary to enhance performance both at fleet level and in the long term.

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MARINE CAPTURE FISHERIES POLICY FORMULATION AND THE ROLE OF MARINE PROTECTED AREAS AS TOOL FOR FISHERIES MANAGEMENT IN INDONESIA

Marine Research in Indonesia ◽

10.14203/mri.v30i0.422 ◽

2018 ◽

Vol 30 ◽

pp. 33-45

Author(s):

D. G.R. Wiadnya ◽

P. J. Mous ◽

R. Djohani ◽

M. V. Erdmann ◽

A. Halim ◽

...

Keyword(s):

Protected Areas ◽

Marine Protected Areas ◽

Scientific Evidence ◽

Code Of Conduct ◽

Fishing Effort ◽

Policy Formulation ◽

Maximum Sustainable Yield ◽

Fish Stocks ◽

Fisheries Policy

The FAO Code of Conduct for Responsible Fisheries states that conservation and management decisions for fisheries should be based on the best scientific evidence available. Studies show that most of Indonesia's capture fisheries are either full or over-exploited. However, the fishery sector is still expected to contribute to the increase of Indonesia's GNP through an increase in total catches. Furthermore, the current practice of using catch-effort data and Maximum Sustainable Yield models to inform Indonesia’s fisheries policies is flawed, putting sustainability and long-term profitability of Indonesia's fisheries at risk. In this paper, the authors argue that to ensure the survival of Indonesia's fish stocks and fisheries: fisheries policy must shift from development-oriented management towards management for sustainability. Furthermore, fisheries managers must accept that 'untapped resources' may not exist or cannot be exploited profitably, and that any transfer of fishing effort between fishing grounds may contribute to collapse of local fisheries. Also, fisheries managers should change the management paradigm from MSY models to eco-system based management, wherein Marine Protected Areas should play an important role.

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Integrating economic dynamics into ecological networks: The case of fishery sustainability

Science Advances ◽

10.1126/sciadv.aaz4891 ◽

2020 ◽

Vol 6 (45) ◽

pp. eaaz4891

Author(s):

Paul Glaum ◽

Valentin Cocco ◽

Fernanda S. Valdovinos

Keyword(s):

Open Access ◽

Large Scale ◽

Anthropogenic Impacts ◽

Management Strategies ◽

Network Models ◽

Single Species ◽

Fishing Effort ◽

Economic Dynamics ◽

Trophic Network

Understanding anthropogenic impacts on ecosystems requires investigating feedback processes between ecological and economic dynamics. While network ecology has advanced our understanding of large-scale communities, it has not robustly coupled economic drivers of anthropogenic impact to ecological outcomes. Leveraging allometric trophic network models, we study such integrated economic-ecological dynamics in the case of fishery sustainability. We incorporate economic drivers of fishing effort into food-web network models, evaluating the dynamics of thousands of single-species fisheries across hundreds of simulated food webs under fixed-effort and open-access management strategies. Analyzing simulation results reveals that harvesting species with high population biomass can initially support fishery persistence but threatens long-term economic and ecological sustainability by indirectly inducing extinction cascades in non-harvested species. This dynamic is exacerbated in open-access fisheries where profit-driven growth in fishing effort increases perturbation strength. Our results demonstrate how network theory provides necessary ecological context when considering the sustainability of economically dynamic fishing effort.

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Long-Term Benefits of Protecting Table Grape Vineyards against Trunk Diseases in the California Desert

Agronomy ◽

10.3390/agronomy10121895 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1895

Author(s):

Carmen Gispert ◽

Jonathan D. Kaplan ◽

Elizabeth Deyett ◽

Philippe E. Rolshausen

Keyword(s):

Economic Benefit ◽

Production Systems ◽

Economic Benefits ◽

Fungal Species ◽

Table Grape ◽

Limiting Factors ◽

Grapevine Trunk Diseases ◽

Trunk Diseases ◽

Marketable Fruit

Grapevine trunk diseases (GTD) are caused by several fungal species and are major limiting factors to vineyard productivity and profitability in all viticulture areas. This study is aimed at addressing the gap in the knowledge with regards to measuring the long-term benefits of post-pruning fungicide application on trunk diseases incidence and crop yield in grape production systems. It also calculated the net economic benefit of implementing such practice over the vineyard lifespan. We selected a newly planted commercial table grape vineyard in the California desert and divided it in two blocks. In one block, the registered fungicide thiophanate-methyl was mechanically applied on pruning wounds for six consecutive years, while the other half remained untreated. Our results showed a significant lower GTD incidence and vine replants in treated blocks combined with a significant increase of total and marketable fruit. Potential annual economic benefits of applying fungicide on pruning wounds appear to be in the range of $8500–$12,500 per hectare annually in a 50–75% disease control scenario.

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Analysis on Economic Benefit of Pavement Layer Based on Net Present Value Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.361-363.1735 ◽

2013 ◽

Vol 361-363 ◽

pp. 1735-1738

Author(s):

Meng Hui Hao ◽

Kun Wang

Keyword(s):

Economic Benefit ◽

Net Present Value ◽

Economic Benefits ◽

Present Value ◽

Modified Asphalt ◽

Absorbing Layer ◽

Emulsified Asphalt

This paper explains the method and theory of cost net present value, and uses this method to analyses the economic benefits on several pavement inter layer (emulsified asphalt seal coat, rubber modified asphalt and stress absorbing layer of fiberglass polyester paving mat) during the 15-year period, results showed that rubber modified asphalt and stress absorbing layer of fiberglass polyester paving mat is superior to emulsified asphalt seal coat.

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Bioeconomic assessment of a change in fishing gear selectivity: the case of a single-species fleet affected by the landing obligation

Scientia Marina ◽

10.3989/scimar.04597.18a ◽

2017 ◽

Vol 81 (3) ◽

pp. 371 ◽

Cited By ~ 10

Author(s):

Raúl Prellezo ◽

Itsaso Carmona ◽

Dorleta García ◽

Luis Arregi ◽

Jon Ruiz ◽

...

Keyword(s):

Labour Productivity ◽

Mesh Size ◽

Single Species ◽

Fishing Effort ◽

Point Of View ◽

Human Consumption ◽

The European Union ◽

Societal Benefit ◽

Gear Selectivity ◽

Fisheries Policy

The European Union Common Fisheries Policy has established a discard ban, which states that fish below a reference size cannot be sold directly for human consumption. In a fishing effort-regulated fishery, the discard ban can result in extra handling, storing and landing costs. In an output-regulated fishery, this policy might also limit the effort levels as all the catches count against the quota. In both cases, this regulation can reduce the economic performance of the companies, even in single-species fisheries. A possible solution is to increase the mesh size, thus retaining fewer small individuals. To study this option, a bioeconomic simulation of a change in the gear selectivity from 100- to 120-mm minimum mesh size (MMS) was performed. The results show that the private perspective (profits) does not change. Furthermore, due to the lower retention of 120 mm MMS, the efficiency of a fishing day was reduced by 5% and 2.5%, from the point of view of capital and labour productivity, respectively. In contrast, gross revenues increased by 1.5% and crew compensation by 2%. Given a societal benefit of this change in the mesh size, this gain could be re-distributed to provide an incentive for selectivity improvements.

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How a catch–quota balancing system can go wrong: an evaluation of the species quota transformation provisions in the Icelandic multispecies demersal fishery

ICES Journal of Marine Science ◽

10.1093/icesjms/fsv001 ◽

2015 ◽

Vol 72 (5) ◽

pp. 1257-1277 ◽

Cited By ~ 7

Author(s):

Pamela J. Woods ◽

Daniel S. Holland ◽

Guðrún Marteinsdóttir ◽

André E. Punt

Keyword(s):

Extreme Case ◽

Single Species ◽

Economic Benefits ◽

Unintended Consequences ◽

Individual Species ◽

Negative Consequences ◽

Quota System ◽

Total Allowable Catch ◽

Stock Depletion

Abstract Implementation of single-species catch limits in multispecies individual quota systems is problematic because it may incentivize discarding behaviour when quotas for some species limit catch of jointly caught species. Since discarding may reduce economic benefits and bias stock assessments, mechanisms that reduce incentives to discard can be beneficial. However, these mechanisms may be detrimental in the long term if they also pose a risk of stock depletion, which can occur if they enable catch to persistently exceed the total allowable catch (TAC). This study uses a bioeconomic model to analyse potential negative consequences of species quota transformation provisions, using the Icelandic individual transferable quota system as a case study. These provisions allow quota of one species to be transformed into quota of another species at specified rates related to relative market value. The system reduces the degree that the TAC of any particular species constrains catch of other species. However, it also allows catches of some species to exceed TACs, possibly leading to stock depletion. We explore how these provisions may affect long-term sustainability of individual species and profitability of the fishery as a whole. We focus on the extreme case of perfect targeting (i.e. full control of catch composition) to increase intuition on the potential for adverse effects of this system. Various combinations of species profitability are examined to determine attributes of species that lead to greater vulnerability, as well as interactions in species utilization. Consequences of changing harvest control rules are explored, and information needed to monitor for unintended consequences of such a system in practice are discussed. Although the species transformation system is designed to increase economic efficiency, our results show that it could lead to depletion in some cases, and may make it difficult to achieve optimal management goals.

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Enhancing community welfare through improved water quality: a case for applying staggered pollution charges in the river Musi sub-basin of Andhra Pradesh, India

Water Policy ◽

10.2166/wp.2005.0028 ◽

2005 ◽

Vol 7 (5) ◽

pp. 469-483

Author(s):

Tishya Chatterjee

Keyword(s):

Andhra Pradesh ◽

Relevant Literature ◽

Pollution Prevention ◽

Economic Benefits ◽

Environmental Damage ◽

Marginal Costs ◽

Community Acceptance ◽

Level Data ◽

Over Time

In conditions of severe water-pollution and dormant community acceptance of accumulating environmental damage, the regulator's role goes beyond pollution prevention and more towards remediation and solutions based on the community's long-term expectations of economic benefits from clean water. This paper suggests a method to enable these benefits to become perceptible progressively, through participatory clean-up operations, supported by staggered pollution charges. It analyses the relevant literature on pollution prevention and applies a cost-based “willingness to pay” model, using primary basin-level data of total marginal costs. It develops a replicable demand-side approach imposing charge-standard targets over time in urban-industrial basins of developing countries.

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