| Abstract |
The aim of the current study was an attempt to investigate the role of temperature, of the concentration of chlorophyll and of the oceanographic processes in the movements of sea turtles Caretta caretta in the Mediterranean Sea. For this purpose we analyzed, through GIS (Geographical Information System) the tracks of eleven turtles in combination with satellite data of sea surface temperature (SST) and sea surface chlorophyll (CHL-a) images, respectively. The results showed that the turtles occupy SST of 15.5 - 26 οC annually and CHL-a of 0,07 -0,93 mg/m3, however there was not revealed any pattern in their movements related with SST and CHL-a. Furthermore was observed that the routes of four turtle seem to be correlated with eddies (cyclones and anticyclones) in east basin of the Mediterranean Sea. One possible explanation may be that the turtles use the cyclonic circulation in their movements to save energy and to satisfy their feeding needs. In the Mediterranean Sea except of the degradation of the nesting areas, the fishing activity seems to be one of the major causes of the sea turtle deaths. In this study we analyzed 386 stranded turtle recorded in the period 1990-2004 at the areas of Crete and Aegean Sea. The turtles that have been analyzed belong to the species Caretta caretta and Chelonia mydas. Most of the deaths were recorded during summer and less during winter. Additionally a high percentage of death turtles concerned individuals that were adults. In the known cases of analyzed sample the major cause of death were fishery activities. To predict the cases were the reason of death was unknown (72%) we applied the method of discriminal analysis. According to our results the major cause of death was due to fishery. There was a positive correlation of the number of stranded turtles and fishing effort of coastal fishery in the period 1995-2004 which appear to be owed to seasonality,due to the increase of fishing activity in the summer.
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Συσχέτιση των μεταναστευτικών προτύπων της θαλάσσιας χελώνας Caretta caretta με ωκεανογραφικές διεργασίες και διερεύνηση της επίδρασης της αλιείας στην θνησιμότητα των χελωνών στην Μεσόγειο
