Fish forced to shallow waters by low oxygen levels
“Preliminary results of the field surveys suggest that the project territories appear to be important for the fish of the Baltic Sea during the summer time: when oxygen levels drop in deeper water layers at the open sea areas, fish seem to move to the shallow areas”, - dr. Linas Lozys head of the Laboratory of Marine Ecology, at the Nature Research Center says.
His team just returned from the summer expedition that focused on gathering data on fish populations at all three project territories.
Even though these observations are preliminary and collected data is still being analysed, it seems that fluctuations in oxygen level are a key factor. “Our survey showed that the most remote area – Klaipeda bank – the abundance of fish is some seven times less than in the other two. These figures correlated with the concentrations of dissolved oxygen which was also the lowest there”, – he adds.
Water depth in all three project territories – Klaipeda Bank, Klaipeda-Ventspils and Sambian Plateu is around 30-40 meters, while in the surrounding territories it goes down to 70-80 meters.
During the four-day expedition two weeks ago scientists were collecting data on fish population biodiversity, gender, size and age structure. For the first time since the beginning of the project Twaite Shad – the species protected under the
European Union’s Habitat Directive was also found in one of the areas.
Expedition image gallery here.
More at corpi.ku.lt/denoflit/
