Warm-water fish species in the northern Baltic Sea

"Occurrence of marine warm-water fish species in the northern Baltic Sea possibly linked to climate change"
Professor Henn Ojaveer and colleagues have recently found the thin-lipped grey mullet inhabiting the waters of the Gulf of Riga, Baltic Sea.

The distribution area of thin-lipped grey mullet, Liza ramada, not only includes the Mediterranean and Black seas, but also the eastern Atlantic Ocean from southern Norway to south Africa. As a habitat, the species prefers brackish coastal areas but also lagoons with varying salinity conditions. The fish can enter rivers for feeding but spawns in the marine environment.
There are very few known records of mullets in the NE Baltic: in Finnish waters in 1923, 1953 (both cases Liza ramada) and in 1958 (species unknown). In mid-October this year, an occurrence of a new species – the thin-lipped grey mullet – was recorded in Estonian waters of the Baltic Sea (Gulf of Riga). This is the third grey mullet individual found in Estonian waters during the past few years (in addition, the thick-lipped grey mullet Chelon labrosus was found in 2003 and 2007).
Mullets are considered to be rare visitors in the NE Baltic and recent more frequent findings are probably due to the extension of the distribution area of these species towards the north of their main distribution area. In this way, the chance of the species entering into the Baltic Sea increases. It is unlikely that these species can establish local populations at least in the northern Baltic because of the low temperatures in winter.

Image courtesy of Vadim Vlassov

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