Children from St Hedda’s Primary School in Egton Bridge said goodbye to their ‘pet’ fish on Tuesday after taking part in a national park breeding programme.
The salmon had been raised from eggs by the children in a special hatchery tank installed in their classroom.
Mari Palmer is head teacher at the school and said: “I think they were quite sad to see them go in a way. They’ve really enjoyed having the fish in the classroom - checking on them every day and desperate to have a turn at feeding them.
“They’ve learnt a lot and it’s been interesting to see them use this knowledge in other areas of their school work.”
The National Park Authority has been running the project since 2009, working with a different primary school in the Esk Valley each year.
Project officer Simon Hirst said: “These fish will remain in the river for around two years until they are big enough to migrate out to sea.
“Hopefully they’ll then return to the Esk in about three years to produce young of their own.”