As part of a move by Portugal to reduce its heavy debt load, the government-owned Lisbon Oceanarium has been sold to Sociedade Francisco Manuel dos Santos for €24m (US$27m, £17m) under a concession deal.

The 30-year deal, which also requires the winner to pay annual rental fee, will see Sociedade Francisco Manuel dos Santos take up management of the aquarium, one of the largest in Europe and also one of the main attractions of the Portuguese capital.

Designed by Cambridge Seven Associates, the aquarium, which resembles an aircraft carrier, first opened in 1998 and houses 16,000 animals across 450 species.

The €24m deal includes the sale of all shares in Lisbon Oceanarium SA – the company that currently manages the facility. Final approval for the deal will now go forward to Portugal’s Conselho de Ministros. After the takeover, predicted revenues for the aquarium for 2015 have been set at €40m (US$44.8m, £28.4m), which last year generated profits of €1.49m (US$1.7m, £1m) drawing one million visitors.

Other bidders for the aquarium included the Spanish group Aspro Parks – which recently lost out on a bid for Spain’s L’Oceanogràfic, Portuguese operator Mundo Aquatico and the French Compagnie des Alpes.