Are tuna fish present in the Baltic sea?
Indeed tuna are present in the Baltic sea, and they can also grow in the Pacific and Indian oceans. A lot of the tuna we see in tuna cans in supermarkets comes from the stocks in the Indian ocean, but it is possible to have fresh tuna from the Baltic.

Sorry, I only found a French answer from a famous French news paper: http://sante.lefigaro.fr/mieux-etre/nutrition-aliments/thon/dou-vient-thon