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You searched for subject:(silver eel). Showing records 1 – 2 of 2 total matches.

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Université du Luxembourg

1. Wendling, David. Entwicklung eines EDV-basierten Frühwarnsystems für die Blankaalabwanderung an der Mosel.

Degree: 2017, Université du Luxembourg

The eel (Anguilla anguilla L.) is a fish that is mainly found in European waters. The River Moselle is among the bodies of water inhabited by this specimen. During the downstream migration into their Atlantic spawning ground, silver eels often experience severe to fatal injuries while passing the turbines at the barrages. This annual migration takes place in a relatively narrow timeframe. Therefore, knowing the trigger or beginning of said migration, the mortality rate of the eels could be reduced by a fish-adapted turbine control or comparable protective measures. This thesis introduces an early warning system, which predicts the periods of silver eel emigration by means of certain abiotic factors. On the basis of the information gleaned from different studies and the experience gained from many years of professional fishing, those environmental factors were identified which are connected with the migration of the silver eel. Extensive data analyses were used to substantiate these findings. The water flow, the flow differences and the lunar phase were particularly relevant. Furthermore, the season and the water temperature were taken into account. In view of the different sources of information (experience and expert knowledge, data sets and the findings derived from it), a hybrid structure of the early warning system was realized. After examining different methods from the fields of soft computing and mathematics or statistics, the fuzzy logic (knowledge-based), the case-based reasoning (casebased) and the artificial neural networks (data-based) were selected. With each of these methods, an independent prediction model was designed, tested and optimized. Special characteristics were found during the data analysis and were taken into account by the use of adequate modifiers. The models were tested on the basis of the present data sets for the Moselle. It was shown that it is possible to correctly predict most of the situations with increased catches (suggesting a migration). Threshold values for a migration were defined based on the catches. The same was done for the forecast values. Thus, for the 1963 to 1973 data record, a total of 63% (artificial neural networks), 74% (fuzzy logic), and 83% (case-based reasoning) of the events with increased catches could be detected. Since not every situation with a favorable constellation of abiotic factors also led to a migration or higher catches, a lot of "false" forecasts (up to 50%) were made as well. Good results have also been achieved when using data from recent years and most events were identified. A stand-alone program was developed for the practical application of the prognosis models. This early warning system is a software which contains a user interface for reading data and displaying prognosis values and into which the developed prognosis models are implemented. In addition, recommendations for use were compiled and presented. Advisors/Committee Members: Hansen, Joachim [superviser].

Subjects/Keywords: silver eel; migration; prediction; Engineering, computing & technology :: Civil engineering [C04]; Ingénierie, informatique & technologie :: Ingénierie civile [C04]

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wendling, D. (2017). Entwicklung eines EDV-basierten Frühwarnsystems für die Blankaalabwanderung an der Mosel. (Doctoral Dissertation). Université du Luxembourg. Retrieved from http://orbilu.uni.lu/handle/10993/30201

Chicago Manual of Style (16th Edition):

Wendling, David. “Entwicklung eines EDV-basierten Frühwarnsystems für die Blankaalabwanderung an der Mosel.” 2017. Doctoral Dissertation, Université du Luxembourg. Accessed October 26, 2020. http://orbilu.uni.lu/handle/10993/30201.

MLA Handbook (7th Edition):

Wendling, David. “Entwicklung eines EDV-basierten Frühwarnsystems für die Blankaalabwanderung an der Mosel.” 2017. Web. 26 Oct 2020.

Vancouver:

Wendling D. Entwicklung eines EDV-basierten Frühwarnsystems für die Blankaalabwanderung an der Mosel. [Internet] [Doctoral dissertation]. Université du Luxembourg; 2017. [cited 2020 Oct 26]. Available from: http://orbilu.uni.lu/handle/10993/30201.

Council of Science Editors:

Wendling D. Entwicklung eines EDV-basierten Frühwarnsystems für die Blankaalabwanderung an der Mosel. [Doctoral Dissertation]. Université du Luxembourg; 2017. Available from: http://orbilu.uni.lu/handle/10993/30201

2. MacNamara, Ruairi. Conservation biology of the European eel (Anguilla anguilla) on a hydropower-regulated Irish river .

Degree: 2012, National University of Ireland – Galway

The European eel (Anguilla anguilla) has a complex lifecycle, involving catadromous migration between marine spawning grounds and continental growth habitat. European eel stocks have undergone a serious population collapse, and recently introduced E.U. legislation (EC 1100/2007) specifies major conservation actions. In particular, the protection of potential spawners (i.e. silver eels) from continental waters is considered essential for stock recovery. Various aspects of silver eel migratory behaviour, population biology and conservation were examined on the hydropower-regulated River Shannon. The primary study site was at Killaloe eel fishing weir, where long-term reliable catch records are available. Ardnacrusha hydropower dam is located 18 km further downstream (near the tidal limit). Since 2000, silver eels captured at Killaloe are released below the hydropower dam as part of a 'trap and transport' conservation strategy. In 2009, Ireland's Eel Management Plan (EMP) specified that 30% of the silver eel production on River Shannon must be captured and released annually. As a result, four additional fishing sites were established in the mid/upper catchment. An estimated 228 013 silver eels, including a high proportion of females (75.9%), have been released to the lower River Shannon (2000-2010), thus avoiding the hazards associated with passage via Ardnacrusha. Analysis of silver eel migration dynamics/population structure on the river has demonstrated how multi-site capture has enabled EMP targets to be achieved (30.2% in 2009, 39.6% in 2010 and 41.9% in 2011), in addition to increasing the quantity of large female eels released. Silver eel trap and transport is ideally an interim conservation measure, pending development of non-intrusive alternatives (e.g. guidance technology, controlled spillage). To ensure effective implementation of these alternatives, accurate prediction of silver eel migration is essential. Therefore, two predictive approaches were evaluated on the lower River Shannon, by reference to silver eel catches at Killaloe: (i) the Migromat® biomonitor, which predicts migration based on the activity levels of captive eels, signalled 19.9-28.9% of the total catch, or 21.4-32.1% of migration events, during the evaluation period; (ii) alternatively, retrospective analysis of catch and environmental data (water temperature, discharge and lunar luminosity) were used to develop logistic regression models for prediction of silver eel migration. The predictive capacity of this approach varied, depending on the year (27.5-86.4% of the total catch, or 66.7-95.0% of migration events), but was generally more effective than the Migromat®. The use of behavioural guidance as a potential hydropower mitigation measure was also evaluated on the lower River Shannon. During an experiment involving an overwater light barrier at Killaloe eel weir, catch patterns were found to be significantly different between lights on and lights off periods. Eel response to the light barrier was size related, reflecting the… Advisors/Committee Members: McCarthy, Thomas K (advisor).

Subjects/Keywords: Silver eel; Anguilla anguilla; Downstream migration; Hydropower; Zoology; Natural Sciences

…continental yellow and silver eel stocks of A. anguilla are also in decline (Dekker, 2000… …be taken in order to comply with a 40% escapement target of silver eel biomass which would… …commercial silver eel fishing in 1937 (McCarthy et al., 2008b). In this thesis, the… …predicting silver eel migration, so as to facilitate effective implementation of hydropower… …x28;Chapter 4), were evaluated by reference to silver eel catches on the lower River… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

MacNamara, R. (2012). Conservation biology of the European eel (Anguilla anguilla) on a hydropower-regulated Irish river . (Thesis). National University of Ireland – Galway. Retrieved from http://hdl.handle.net/10379/3108

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

MacNamara, Ruairi. “Conservation biology of the European eel (Anguilla anguilla) on a hydropower-regulated Irish river .” 2012. Thesis, National University of Ireland – Galway. Accessed October 26, 2020. http://hdl.handle.net/10379/3108.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

MacNamara, Ruairi. “Conservation biology of the European eel (Anguilla anguilla) on a hydropower-regulated Irish river .” 2012. Web. 26 Oct 2020.

Vancouver:

MacNamara R. Conservation biology of the European eel (Anguilla anguilla) on a hydropower-regulated Irish river . [Internet] [Thesis]. National University of Ireland – Galway; 2012. [cited 2020 Oct 26]. Available from: http://hdl.handle.net/10379/3108.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

MacNamara R. Conservation biology of the European eel (Anguilla anguilla) on a hydropower-regulated Irish river . [Thesis]. National University of Ireland – Galway; 2012. Available from: http://hdl.handle.net/10379/3108

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.