Using a coupled behavior-economic model to reduce uncertainty and assess fishery management in a data-limited, small-scale fishery

2014 ◽  
Vol 102 ◽  
pp. 94-104 ◽  
Author(s):  
Liam M. Carr ◽  
William D. Heyman
2020 ◽  
Vol 12 (18) ◽  
pp. 7299
Author(s):  
Pina Lena Lammers ◽  
Torsten Richter ◽  
Jasmin Mantilla-Contreras

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.


Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1509 ◽  
Author(s):  
Kyriakoula Roditi ◽  
Dimitris Vafidis

Small-scale fisheries constitute an important component of coastal human societies. The present study describes the small-scale net fisheries on Kalymnos Island (south-east Aegean Sea) that harbors the largest small-scale fleet in the eastern Mediterranean Sea. In addition, this study aims to evaluate their characteristics and economics. Relevant métiers were identified through a multivariate analysis by inputting the main resources and fishing gear data that were recorded during landings. Four main practices were observed being used as fishing gears, gillnets and trammel nets, targeting the species Mullus barbatus, Boops boops, Mullus surmuletus, Scorpaena porcus, and Sepia officinalis. Further analysis, which incorporated data concerning the type of the gear used, revealed 11 distinct métiers. Most of these métiers are practiced by other Mediterranean small-scale fisheries as well, in terms of target species, gear and seasonality. However, the métier that had its target species as B.boops is not practiced in other Mediterranean small-scale fisheries. The seasonal rotation of métiers was determined by the availability of different species rather than their market price. The results revealed the difference in fishing practice used by the fishermen in the study area compared to other fishing practices in the Mediterranean Sea. In particular, the fishermen of this study area targeted more species (B.boops) with a very low market price. They also provided essential information for the development and implementation of management plans aiming at the sustainability of small-scale fisheries.


2007 ◽  
Vol 64 (11) ◽  
pp. 1595-1604 ◽  
Author(s):  
Kirsten E Abernethy ◽  
Edward H Allison ◽  
Philip P Molloy ◽  
Isabelle M Côté

We used the theory of the ideal free distribution (IFD) as a framework to understand the mechanisms underlying fishing site selection by Anguillian artisanal fishers exploiting shallow-water coral reefs. Contrary to the predictions of IFD, fishers did not distribute themselves so that average reward was equal among fishers using different fishing methods or among fishers using the same method. In addition, fishing pressure did not increase with resource availability. Key assumptions of the IFD were not met. The distribution of Anguillian fishers was not "ideal" because lack of knowledge prevented fishers from choosing fishing grounds with the greatest rewards. Not all fishers sought to maximise profit. In addition, all fishers were not "free" to distribute themselves among reefs owing to variation in social, economic, and physical characteristics of fishers that constrained fisher movements and ability to extract resources. This study shows that as a null model the IFD is useful to frame studies designed to gain detailed insights into the complexity and dynamics of a small-scale fishery. Alongside ecological data, this framework may inform efficient and effective development of reef and fishery management practice.


1973 ◽  
Vol 30 (12) ◽  
pp. 2386-2392
Author(s):  
W. F. Royce

The salmon fishery of the United States illustrates the major principles and problems of fishery management: regulation of the fishery, maintenance of the environment, and artificial augmentation of the stocks. It also includes controls both in fresh water and on the high seas. The industry has experienced the age-old conflicts between large- and small-scale fisheries, and administrators have had to wrestle with the problem of allocating the catch among various contenders. This problem has been confused with that of conservation. Prohibition of salmon traps, restrictions on size and mode of operation of purse seines, and prohibition of monofilament gillnets are examples of the kinds of compromises made between allocation and conservation.Dams, pollution, and other modifications of the freshwater environment have endangered salmon stocks. An early response was to raise salmon artificially and release them. For many years this technique was unsuccessful, and when it was evaluated most hatcheries were closed. In recent years the preservation of the genetic identity of the stock and improved diets and schedules of release have resulted in greater success of hatcheries. Spawning channels show promise of additional success. Another practice of value has been development of devices to pass fish over dams, both upstream and down.Control of fishing to provide adequate spawning has concentrated on manipulation of individual population units, an enormously complicated task since the number of these in United States streams is in the order of 10,000. Of these about 100 major ones are under separate control. Regulations depend on forecasts, since fishing takes place before the salmon reach spawning grounds. Forecasts have improved greatly in recent years, although much remains to be done.Among problems on which no great progress has been made are: extent and consequences of genetic change produced by selective fishing; causes of cycles, and alterations in these; effects of changing environment, especially subtle ones of temperature, dissolved oxygen, and pollution; control of recruitment, including release of hardy young. Difficult economic problems include: the tendency for regulations to favor inefficient operators; high costs of research and regulation, borne not by users but by public funds.Administrative achievements include: a high degree of environmental protection; remarkably parallel regulations in the three States principally involved, Alaska, Washington, and Oregon; successful joint regulation of international fisheries in cooperation with Canada and Japan.Problems which will continue to exist and increase in difficulty include protection of the environment of the salmon, rivalries between many diverse interest groups, and improvement in culture operations. The major step of restricting entry into the commercial salmon fishery is being contemplated in several locations.


2015 ◽  
Vol 21 (1) ◽  
pp. 53
Author(s):  
Duto Nugroho ◽  
Ria Faizah ◽  
Andhika P. Prasetyo ◽  
M. Badrudin

North Kalimantan Province, notably Tarakan City marine waters, is one of the important fishing ground in boundary area among Sulu Sulawesi Marine Ecoregion. It produces approximately 100 mt/annum of Bombay duck (<em>Harpadon nehereus</em>) with valued of US$ 750,000. The sustainability of this fishery is a crucially concern given the following: substantial economic contribution, significant dependence of small-scale fishers on this species for their livelihoods. The fishing intensities considerable and growing threats to their habitats. To evaluate the vulnerability of individual species to over exploitation, the spawning potential ratio (SPR) approach applied to describe the status of its existing fisheries. This approach provides the ability to determine fishing mortality as reference points to enhance its sustainability. The objective of this study is to understand this fish biomass resilience to harvesting. The calculated SPR based on the value of estimated length of first capture or Lc at 208 mm is equivalent to the SPR of 28%. With a base line of stocks are generally thought to risk recruitment declining when SPR &lt;20%, recent finding indicated that the existing fishery can be generally described as nearly fully exploited. In recognition of this sector’s has an ecological importance and socio-economic significance, the sustainable development of Bombay duck fisheries should be initiated through developing local fishery committee to provide a their local fishery management plan.


2021 ◽  
Vol 34 ◽  
pp. 6
Author(s):  
Alicia Mallet ◽  
Jean-Yves Jouvenel ◽  
Morgane Broyon ◽  
Nelly Pirot ◽  
Benjamin Geffroy

The mutable nassa, Tritia mutabilis, a marine gastropod that is widely exploited on the Adriatic coast is an important source of income for small-scale fishermen in the Mediterranean Sea, particularly in the Gulf of Lion. However, the lack of knowledge on the ecology and biology of this species limits our capacities to propose and produce an effective management plan. As a result, stocks are currently declining, especially in Italy. In order to optimize a management plan for this fishery, we designed a study to better characterize the reproductive biology of T. mutabilis, using gonad histology and performing a regular monitoring of population size frequency. The average shell height of individuals during the breeding period was 24 ± 2.7 mm for males and 30 ± 3.7 mm for females. The presence of small females (10 mm) and large males (32 mm) in the whole sample challenged previous assumptions regarding protandry (sex change from male to female). The size at first maturity was estimated for males and females at 17.5 mm and 24.4 mm shell height, respectively. In Italy, current management measures include a minimum conservation reference size of 20 mm in shell height. Therefore, it is likely that many individuals that did not reproduce are being caught, which could partly explain the decline observed, despite conservation measures introduced more than ten years ago. Overall, our study provides some baseline information to establish, in consultation with fishermen, management measures for this small-scale fishery in France.


2019 ◽  
pp. 92-106
Author(s):  
Valter Silva ◽  
João Cardoso ◽  
Paulo Brito ◽  
Luís Tarelho ◽  
José Luz

Municipal solid waste provides an opportunity for electricity production. This strategy provides the rural communities a potential waste-to-energy opportunity to manage its costly residues problem, turning them into a valuable recycled asset. To address this issue, a techno-economic study of an integrated system comprising gasification of Acacia residues and Portuguese Municipal Solid Waste (PMSW) with an Internal Combustion Engine-Generator (ICEG) for electricity generation at small-scale (100 kW) was developed. Current studies only devote attention to biomass residues and do not explore MSW potential to eschew biomass supply shortage. Conventional systems are generally part of biomass supply chains, limiting flexibility and all year operation for their operators. Experimental data was gathered at a downdraft gasifier to provide a clear assessment of particle and tar concentration in the syngas and levers conditioning a satisfactory ICE operation. Once the potential of using Acacia residues and PMSW has been proven during gasification runs testing, and validation, a set of new conditions was also explored through a high-fidelity CFD model. We find that residues blends have the highest potential to generate high-quality syngas and smallest exposure to supply disruption. Despite both substrates showing potential at specific conditions, they also present individual drawbacks which will be best mitigated by executing a hybrid supply comprising the mix of substrates. An economic model coupling the financial indicators of net present value (NPV), internal rate of return (IRR) and the payback period (PBP) considering a project lifetime of 25 years was developed. Cost factors include expenses with electricity generation, initial investment, amortizations and operation and maintenance (containing fuels costs). Revenues were estimated from electricity generated and sales to the national grid. A sensitivity analysis based on the Monte Carlo method was used to measure the economic model performance and to determine the risk in investing in such venture. The risk appraisal yielded favorable investment projections, with an NPV reaching positive values, an IRR superior to the discount rate and PBP lower than the project life span. This work allowed to confirm the positive effect of the generation of energy from downdraft gasification plants on a small-scale. Regardless of the project’s feasibility, the economic performance depended to a large extent on the electricity prices which present considerable variability and are subject to political decisions.


2014 ◽  
Vol 6 (2) ◽  
pp. 55
Author(s):  
Duto Nugroho ◽  
Suherman Banon Atmaja

<p>Kajian terhadap perikanan cantrang yang beroperasi di Laut Jawa dengan menggunakan perangkat pengelolaan cenderung dikategorikan sebagai perikanan akses terbuka. Penambahan armada secara historis memperlihatkan rendahnya pertimbangan terhadap pentingnya kelestarian sumber daya ikan, bebas beroperasi dan dalam banyak kasus tidak dikelola sesuai tatalaksana perikanan secara bertanggung jawab. Hasil penelitian menunjukkan sebagian besar armada cantrang dengan izin daerah melakukan penangkapan di luar batas 12 mil laut dan beroperasi di kawasan yang berdasarkan ketentuan diperuntukan bagi nelayan skala kecil yang bukan merupakan wewenang pemberi ijin armada cantrang dari panyai Utara Jawa. Studi kasus dilakukan di Pelabuhan Perikanan Tegal, ditujukan untuk menggambarkan sistem pendataan aktivitas penangkapan yang sedang berjalan. Hal ini berkaitan dengan sistem pencatatan data dan informasi perikanan setempat memiliki kemampuan dan kapasitas terbatas terutama pada sistem pemantauan, pengendalian dan pengawasan untuk melaksanakan pengelolaan perikanan berdasarkan prinsip tata laksana pemanfaatan secara berkelanjutan sesuai peraturan dan keputusan teknis. Terbatasnya pemahaman tentang dampak praktek perikanan tidak berkelanjutan, baik pada tingkat pelaku dan pembuat kebijakan merupakan permasalahan yang harus segera dipecahkan. Kajian ini menyimpulkan bahwa sistem yang berjalan hanya mampu merekam data kurang dari sepertiganya dan penerapan perikanan secara bertanggung jawab pada perikanan cantrang memberikan indikasi pada tingkat yang mengkhawatirkan terutama berdasarkan pertimbangan biologi, eksploitasi dan kelestarian lingkungan, serta memiliki potensi terjadinya unreported yang mengarah pada praktek IUU fishing. Temuan ini diharapkan dapat memperkuat tersedianya landasan pengelolaan perikanan terkait pemulihan sumberdaya ikan demersal bagi kepentingan pengembangan perikanan dalam jangka panjang di Laut Jawa.</p><p> </p><p>Study on demersal danish seine fishery operating in the Java Sea tend to be categorized as an open access fishery. The historical fleet development indicate no limited access to exploit demersal fish resources, which is in many cases the fishery are not well managed in a responsible manner. Study indicates that most of license to fish of demersal danish seine operate in areas outside 12 nm, somehow fleets operated in the area for small-scale fishers in the nearby coastal area beyond the origin of license authority. The objective is to describe the existing data collecting system. This corresponds to the limitation of capacity of the catch in one of fishing port. The data collecting system of local fisheries services has a limited capacity, particularly in monitoring, control and surveillance to implement best practices of fisheries management that declared through several technical reference points. Increasing awareness by complying with management measures of business sectors and policy makers must be immediately resolved. This study indicates current system covered less than a third of its landing data and it would affect the implementation of responsible fisheries based on bio-exploitation and environmental sustainability indicators on demersal fishery. It also has a potential on unreported that lead to IUU fishing practices. This should considered that bias of data could affect the accuracy of regular fish stock assessment. This finding should be treated to strengthen the long-term demersal danish seine fishery management plan as a baseline of sustainable demersal fish resources in the Java Sea.</p>


2017 ◽  
Vol 24 (1) ◽  
pp. 595 ◽  
Author(s):  
Emma McGuirk

Abstract A movement is gaining traction in New Zealand around timebanks, networks of support in which members exchange favors such as gardening, lifts to the supermarket, pet care, language lessons, career advice, or smartphone tutorials. An online currency is used to track these exchanges, with one hour of work earning one time credit. While each transaction may seem commonplace, when timebanks flourish they work to reshape motivations and opportunities for engaging in labor, and relocalize networks of solidarity, friendship, and resources. Participants reported examples of developing unexpected friendships and renewed enthusiasm for a larger collective project of building alternatives to the currently dominant growth-addicted economic model. These processes contribute to the establishment of foundational, mostly small-scale networks that are enjoyable to use in the here and now, while also creating the potential for these systems to be scaled up or linked together in response to greater economic, ecological, and social changes. Timebank developers in New Zealand are negotiating several structural challenges in their attempts to bring these networks to fruition. This article shares results of ethnographic research amongst seven North Island timebanks, and offers suggestions for future research in this area. Keywords: timebank, community currency, activism, degrowth, New Zealand


2006 ◽  
Vol 66 (4) ◽  
pp. 963-973 ◽  
Author(s):  
T. A. Cardoso ◽  
N. Nordi

This work was carried out in the Enseada da Baleia and Vila Rápida communities. Data was provided by the Co-Management Committee of the Cardoso Island State Park (PEIC) on manjuba fishery management, technique and strategies used by the fishermen, as well as locally accumulated knowledge. Based on the results, social, ecological, and economic aspects of this type of fishing were analyzed. The importance of the accumulated knowledge and experience of this community, as well as the limitations imposed by local fishing gear, was concluded to be essential in conserving manjuba fishery conditions in the area. Industrial fishing, relevant state legislation, and market conditions were found to be the main obstacles to local fishery. Various proposals are suggested for manjuba fishery management, with emphasis on the need for fishing community participation in whatever measures are ultimately implemented.


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