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Home    Μοντελοποίηση της παρουσίας σχολείων νεαρών ατόμων του γαύρου (Engraulis encrasicolus L.) και της σαρδέλας (Sardina pilchardus W.) σε σχέση με περιβαλλοντικούς παράγοντες στην περιοχή του Βορείου Αιγαίου  

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Identifier 000334412
Title Μοντελοποίηση της παρουσίας σχολείων νεαρών ατόμων του γαύρου (Engraulis encrasicolus L.) και της σαρδέλας (Sardina pilchardus W.) σε σχέση με περιβαλλοντικούς παράγοντες στην περιοχή του Βορείου Αιγαίου
Alternative Title Modelling the presence of juvenile anchovy (Engraulis encrasicolus L.) and juvenile sardine (Sardina pilchardus W.) schools in relations to enviromental parameters in North Aegean Sea
Author Πυρουνάκη, Μαρία-Μυρτώ
Thesis advisor Μαχιάς, Αθανάσιος
Abstract Acoustic and environmental data were used to model the presence/absence and sound backscatter strength of juvenile anchovy (Engraulis encrasicolus) and juvenile sardine (Sardina pilchardus) schools in the Thracian Sea and Strymonikos gulf (northern Aegean Sea). Generalized Additive Models (GAMs) were used for modelling and the models divided to two categories: (a) the explanatory GAMs based on in situ environmental data were used in order to inform us about the preferences of the juvenile anchovy and sardine in the environment in which they live and (b) the predictive GAMs based on satellite environmental data were used to identify those areas in the Thracian Sea and the Strymonikos gulf that could support species’ presence or species’ high abundance. The presence/absence models were evaluated with the estimation of Receiver Operating Characteristic (ROC)-plots and the models of sound backscatter strength were evaluated qualitatively, using comparative maps of observed-measured values in the study area. The presence/absence explanatory models estimated that: (a) juvenile sardine schools prefer a high range of chlorophyll concentrations (0,02-0,05 μg/l & 0,08-0,14 μg/l), the middle zooplankton concentrations of the available ones (360-630 mg/m2), the middle salinity values in the upper mixed layer (UML) of the available ones (35,1-36,8 psu) and UML ranges < 35m, and (b) juvenile anchovy schools prefer bottom depths 33-102m and salinity values in the bottom layer (BL) between 37 and 38 psu. The results of the predictive models indicated that juvenile sardine and anchovy schools concentrate mainly in gulfs where large rivers outflow, near estuaries and near the coasts. Similar habitats have been observed to be preferred to the juveniles of the two species in the greater Greece and Mediterranean area.
Language Greek
Subject Model GAMs
anchovy
sadrine
Μοντέλα GAMs
Issue date 2008-12-04
Collection   School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
  Type of Work--Post-graduate theses
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