First raised trout released from AquaZoo

The first young sea trout from the nursery at AquaZoo have been released into a Dutch stream. This release marks an important step in the recovery of the iconic fish species, which is still rare in Dutch waters. The collaboration between AquaZoo, Sportvisserij Nederland and the Waddenvereniging builds on the Fish for Connection project.

The sea trout is originally a native species that lived in Dutch streams and rivers, but is hardly found there nowadays. Causes include migration barriers, deteriorating water quality and the disappearance of suitable habitat. With the Fish for Connection project, the collaborating organizations hope to turn that tide, with the release of the trout being one of the final steps in the process.

The young fish come from North German farms, where eggs of wild sea trout were collected. They were then further raised at AquaZoo. William Kreijkes, head of animal care, explains: "Thousands of young sea trout are raised in special tanks. When they are strong enough, they are allowed to be released into the wild."

From stream to sea

The young trout have been released by AquaZoo and Sportvisserij Nederland into a stream in Drenthe. After one to two years, these fish will make the migration to the Wadden Sea and continue to grow. After an average of one to three years at sea, they instinctively try to return to the stream where they were once released, where they reproduce. To make this possible, organizations such as the Waddenvereniging and Sportvisserij Nederland have restored migration routes and improved habitat with juvenile and spawning areas.

"The sea trout is now often still a wanderer in our waters," says Marcus de Boer of Sportvisserij Nederland. "With returning adult sea trout, this stocking would have been successful."

Monitoring and follow-up

The rearing program at AquaZoo will continue in the coming years. In the past, trout have previously been released from the project, with some being tagged. This showed that the fish indeed know how to find their way to the sea. De Boer: "The monitoring now focuses on the survival of the young trout in the stream. In the future, we want to transmit adult trout that return to follow their upstream migration."

Visitors to AquaZoo can learn more about this special project through interactive education boards in the park's Wadden area. There they explain how the restoration of migration routes helps not only the sea trout, but also other fish species - and thus birds, seals and the entire ecosystem.