Atlantic tuna have begun to reappear in the Øresund, signaling the start of their annual feeding frenzy. These magnificent creatures, weighing several hundred kilos, will be hunting herring, mackerel, and garfish in the waters between Denmark and Sweden during August and September. Tickets for tuna-watching tours are already selling fast.

The return of the tuna is a conservation success story, as they had previously disappeared from the Øresund due to overfishing.

Museum Director Jens Peder Jeppesen from the Øresund Aquarium reports that the first tuna have been spotted off Hornbæk Plantation. These early arrivals may be scouting for the main schools of herring and mackerel that will soon migrate into the Øresund.

The tuna follow these fish, finding also garfish that are leaving the Baltic Sea after spawning.

Despite their ability to reach speeds of 60-70 kilometers per hour while hunting, the tuna typically cruise at a more leisurely pace of 3.6 km per hour during their long journey. This “cruising speed” allows them to conserve energy for hunting.

The Øresund Aquarium is offering tuna safaris from August 1st. The best chance to spot the tuna from land is on a quiet evening from locations such as Hornbæk Plantation, Kronborg Point, or the platform in Helsingør North Harbor.

Major restrictions on tuna fishing introduced 20-25 years ago have allowed the fish to grow large enough to migrate from the Mediterranean and eastern Atlantic to the Skagerrak and then into the Øresund.

Tuna were absent from the Øresund for many years, with the last large animal caught in the mid-1960s. The species, native to the Mediterranean, had dwindled in size due to overfishing.

The return of the tuna began around 2010, with increasing numbers observed in recent years. Now, hundreds of tuna jumps are seen on some safaris.

After the feeding frenzy concludes in a few months, the tuna will return to the eastern Atlantic and the Mediterranean.