• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • 1
  • Tagged with
  • 5
  • 5
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Investigating ecosystem-level effects of gillnet bycatch in Lake Erie: implications for commercial fisheries management

Li, Yan 17 August 2010 (has links)
Lake Erie supports one of the world's largest freshwater commercial fisheries. Bycatch has become a concern in current fisheries management. This study focused on four species in Lake Erie that include two major commercial and recreational species, walleye (Sander vitreus) and yellow perch (Perca flavescens); an invasive species, white perch (Morone americana); and an endangered species, lake sturgeon (Acipenser fulvescens). The analyses were based on two datasets, the Partnership Index Fishing Survey (PIS) data and the commercial gillnet logbook data. The bycatch of walleye, yellow perch and white perch was predicted by a delta model developed on the PIS data. Discards were estimated as the difference between predicted bycatch and landed bycatch. Results highlighted bycatch and discard hotspots for these three species that have great management implications. Three classification tree models, a conditional inference tree and two exhaustive search-based trees, were constructed using the PIS data to estimate the probability of obtaining lake sturgeon bycach under specific environmental and gillnet fishing conditions. Lake sturgeon bycatch was most likely to be observed in the west basin of Lake Erie. The AdaBoost algorithm was applied in conjunction with the generalized linear/additive models to analyze catch rates of walleye, yellow perch and white perch. Three- and five-fold cross-validations were conducted to evaluate the performance of each candidate model. Results indicated that the Delta-AdaBoost model yielded the smallest training error and test error on average. I recommend the Delta-AdaBoost model for catch and bycatch analyses when data contain a high percentage of zeros. / Master of Science
2

The Predictive Power of Commercial Fisheries Stock Assessments

Docking, Kathryn A 12 September 2018 (has links)
Organizations responsible for managing commercial fisheries conduct annual stock assessments to monitor stock and, in principle, reduce the risk of overexploitation. These are fundamental to setting the total allowable catch for the upcoming fishing year. While there have been many attempts to estimate uncertainty associated with certain components and estimates of stock assessments, to date there has been no systematic assessment of their forecasted predicted value. Using data from annual stock assessments from 65 commercial fisheries around the world, estimates were obtained of both predicted (from the previous year) and observed (in the current year) catch-at-age. When comparing observed (actual) and predicted catch-at-age for a given stock, estimates were obtained of the predictive power of next-season forecasts. Using other attributes of the fishery and the stock (biological (e.g. life history) and management (e.g. assessment model employed)), empirical models were constructed that attempt to determine variability in predictive power among stocks. It was observed that, on average, within-year predictive powers (age-series within time samples) were higher than year over year predictive powers (time-series within age samples). While focusing on time-series within age, it was observed that change over the period of record (in natural mortality rate, assessment model employed, etc.) reduced predictive power; while for age-series within time, it was shown that cumulative landings reduced predictive power. This study represents one of the first attempts to quantify systematically the predictive power of fisheries stock assessment models.
3

Bendrosios žuvininkystės politikos įgyvendinimas Lietuvoje: verslinės žvejybos kontrolės mechanizmas / Implementation of EU Common Fisheries Policy in Lithuania: Commercial Fisheries Control Mechanism

Lukaševičiūtė, Aistė 20 June 2014 (has links)
Žuvininkystės politika yra kompleksiška sritis, kurioje būtinas balansas tarp socialinių, ekonominių ir aplinkosauginių priemonių, kurios yra neatsiejamos viena nuo kitos. Ekonomikos augimas, darbo vietų stabilumas, verslo plėtra tiesiogiai priklauso nuo žuvų išteklių apsaugos efektyvumo. Lietuva, 2004 m. prisijungusi prie Europos Sąjungos, prisiėmė pareigą ir atsakomybę prisidėti prie bendrosios žuvininkystės politikos įgyvendinimo, tad nors žuvininkystės pramonė Lietuvoje yra nedidelė veiklos šaka, Lietuvos, kaip ir kitų ES šalių, veiksmai prisideda prie bendro siekio – darnios žuvininkystės sektoriaus plėtros. Lietuvoje į žuvininkystės politikos formavimą ir įgyvendinimą įtraukiamos įvairios mokslo ir tyrimo institucijos, tačiau jos vykdo taikomojo pobūdžio tyrimus apie žuvų išteklių ir vandens telkinių būklę, tuo tarpu žuvininkystės politikos formavimas ir įgyvendinimas yra menkai ištirta sritis. Tačiau tarp institucijų egzistuoja horizontalūs ir vertikalūs santykiai, nuo kurių priklauso žuvininkystės politikos formavimas ir įgyvendinimas. Verslinės žvejybos kontrolė yra plačiai reglamentuota ir itin reikšminga žuvininkystės politikos dalis, todėl siekiant užtikrinti efektyvų jos įgyvendinimą svarbu išanalizuoti kontrolės sistemos problemas. Taigi šio darbo tikslas yra ištirti ES bendrosios žuvininkystės politikos įgyvendinimą Lietuvoje verslinės žvejybos kontrolės srityje. Darbą sudaro 5 dalys. Pirmoje darbo dalyje ES bendroji žuvininkystės politika nagrinėjama... [toliau žr. visą tekstą] / Fisheries policy is a complex subject; therefore balance between social, economical and environmental instruments takes important role at this topic. Economic growth, stability of labor market and business development is directly related with efficiency of fish resources protection. In 2004 Lithuanian became European Union member and took obligation and responsibility to take part in the Common Fisheries policy. Although Lithuanian fisheries industry is small in compeer to EU, but it is as important as any other EU member state actions for common aim – sustainable development of fisheries sector. In Lithuanian various science and research institutions are involved Fisheries policy process but those institutions perform empirical researches on conditions of fish and water resources. Meanwhile Fisheries policy is under researched subject. Horizontal and vertical relations existing between institutions have impact on quality of Common Fisheries Policy formation and implantation. Commercial Fisheries control takes a significant part in fisheries policy and is strongly regulated; therefore to ensure successful implementation of policy it is important to analyze problems of control system. The aim of this thesis is to analyze European Union Common Fisheries policy implementation in Lithuanian commercial fisheries control mechanism. The first chapter analyzes EU common fisheries policy by institutionalism and agent – principal theories. This chapter discusses E. Ostrom, S. Jentoft... [to full text]
4

Indigenous fisheries and food security: Norway House Cree Nation, Manitoba, Canada

Islam, Durdana January 1900 (has links)
This thesis addresses food insecurity from an Indigenous fisheries lens and presents a conceptual model by integrating three different but inter-related domains (ecological, cultural, and business) that impact Indigenous food security. Under the broader umbrella of fisheries and food security, the thesis addresses four objectives: (i) to investigate the co-existence of commercial and subsistence fisheries, (ii) to assess food security among commercial and subsistence fishing households, (iii) to explore the meaning of traditional food by engaging Indigenous youth with an objective to revitalize culture, and (iv) to examine the role of the fisherman’s co-operative as a social enterprise to address community economic development. The study was conducted over a period of 14 months (from September 2013 to December 2014) in Norway House Cree Nation, northern Manitoba, Canada. Community members are engaged in both subsistence and commercial fishing. The two kinds of fisheries co-exist, and potential problems of overlap are handled by temporal separation; spatial separation; formal mechanism of monitoring of net ownership; and informal communication for conflict resolution consistent with Cree values. The study found that extensive sharing of fish and other traditional foods by commercial fishers reached almost half of the total population in the community and contributed to improving food security. I used a participatory research approach to engage Indigenous youth to explore the meaning of traditional food. Participants produced a collaborative artwork on the theme of “what traditional food means to you?” This art work functioned as a boundary object, initiating discussion about food security planning in the community. Norway House Fisherman’s Co-op operates as a social enterprise mainly because of fish sharing and its role in business diversification for community economic development. The Chief and Band Council requested an exploration of ways to add value to their existing commercial fisheries. Based on the findings, further development can rely on: (i) better use of existing fish resources, such as the by-catch, (ii) fishing related economic development, such as value-added fish products, and (iii) use of options regarding regulatory bodies, such as eco-certification. / February 2017
5

Combining Balanced Score Card and Data Envelopment Analysis for Analyzing the Performance of Small Scale Fisheries

Rezaei, Mona January 2015 (has links)
The balanced scorecard (BSC) is an accepted methodology for putting strategy into action. The BSC provides a comprehensive performance measurement for an organization with respect to both financial and non-financial perspectives, including the triple bottom line of planet, people, and profit. Through various implementations to companies, organizations, and sectors, balanced scorecards have been used widely both for strategic purposes, as well as for more tactical focus for auditing current performance. BSC implementation is particularly adequate when integrated with the operational processes of the organization. The integration between the strategic plan and the financial and operational plans proceed via the business process model that covers the operational processes associated with the objectives of the organization in the strategy map. In this way, BSC is a tool for real-time monitoring of performance as well as providing the crucial linkage to the organization’s strategy that enables the proper implementation of the organization’s strategy. Data envelopment analysis (DEA) has been widely applied for measuring the efficiency of a specific decision-making unit (DMU) against a projected point on an efficiency frontier. DEA is therefore particularly suitable for measuring the organizational efficiency based on the BSC indicators, which are defined as Key Performance Indicators (KPIs). In the commercial fisheries sector, sustainable strategy of fisheries organizations can be gained by running the current operations more effectively, and by integrating processes enabling adaptation to change. The efficiency frontier of the DEA model can be used to calculate the efficiency of fisheries operations. The proposed research is undertaken as part of the Canadian Fisheries Research Network (CFRN) to investigate the application of BSC and DEA for defining commercial fisheries performance evaluation variables with respect to the objectives of environmental sustainability, economic viability, and social and cultural stability in compliance with, and in the absence of, performance monitoring alleged in the Fisheries and Oceans, Canada Integrated Fisheries Management Plans (IFMP). The combination of BSC-DEA methodologies is developed in this research as a required performance monitoring system suitable for IFMPs for analyzing the relative efficiency of commercial fisheries case studies across Canada towards incorporating best sustainable practices in the industry.

Page generated in 0.0895 seconds