Unit:
Κατεύθυνση Βιολογική ΩκεανογραφίαLibrary of the School of Science
Supervisors info:
Διονύσιος Ε. Ραΐτσος, Αναπληρωτής Καθηγητής, ΕΚΠΑ
Ευάγγελος Τζανάτος, Επίκουρος Καθηγητής, Πανεπιστήμιο Πατρών
Περσεφόνη Μεγαλοφώνου, Καθηγήτρια, ΕΚΠΑ
Original Title:
Συσχέτιση φαινολογίας φυτοπλαγκτού µε την ποσότητα αλίευσης μικρών πελαγικών ιχθύων (γαύρου και σαρδέλας) στη Μεσόγειο Θάλασσα µε έμφαση τα ελληνικά ύδατα
Translated title:
Correlation of phytoplankton phenology with the amount of catch of small pelagic fish (anchovy and sardine) in the Mediterranean Sea with an emphasis on Greek waters
Summary:
In oligotrophic systems, nutrients abundance can be an important factor shaping trophic chains and determining species presence, because it is temporally and spatially limited. Especially in the Mediterranean Sea, small pelagic fish are dominant species due to their trophic habits which are based on plankton. So, they are directly affected by primary production as they prey on planktonic populations. The aim of this work is to attempt to estimate a possible relationship between chlorophyl a concentration and fish biomass of the small pelagic species Engraulis encrasicolus (European anchovy) and Sardina pilchardus (European pilchard) in Greek waters. Specifically, it is examined whether phytoplankton abundance affects directly anchovy and sardine populations. Firstly, environmental factors that influence chlorophyl a concentration, such as sea surface temperature, precipitation rate and wind speed, are studied. The results have shown a positive correlation of chlorophyl a with precipitation rate and wind speed, but there is a negative one with temperature. From the examination of chlorophyl a and fish abundance correlations, it appears that available data are not sufficient to make definitive conclusions, as most correlation values were not statistically significant. However, the variance of chlorophyl a concertation was found to be related to the anchovy/sardine abundance ratio, especially in the Aegean Sea. This is expected, since these populations are clearly interacting and their abundance is determined both by environmental and economic factors. The outcome of this study calls for further research of the relationship between chlorophyl a and fish abundance ratio in order to comprehend fish stock fluctuations and the influence of climate change on the abundance of marine populations.
Main subject category:
Science
Keywords:
chlorophyl a concentration, fish ratio, sea surface temperature, precipitation rate, wind speed
