In total 17,000lb of trout – equivalent to the weight of a male killer whale – are being used to boost fish stocks along with 8,000 rainbow trout.
Colin Winterburn, warden for Yorkshire Water's Washburn Valley sites, said: "Our fisheries have never looked better and with the promise of plenty more trout to be added to our water over the next eight months, anglers and fishing enthusiasts alike can look forward with baited breath to a great season ahead."
Blue trout in particular have a reputation for putting up a real fight when caught to such an extent that they've even snapped rods in the past.
From Sunday 25 March the Washburn Valley Game Fisheries will be open seven days a week between 7.30am and one hour before sunset.
And the water firm says bird enthusiasts also have something to look forward to this spring, with the expected return of a number of migratory bird species to the Washburn Valley this month. Fish eating Ospreys may be seen taking advantage of the valley's plentiful supply of food, while willow warblers and chiff chaffs should be visible in the woodlands that surround the reservoirs as they set up their summer homes.
Colin added: "With spring arriving early this year, the Washburn Valley is already buzzing with animal activity, with lots of species flitting around as they begin their preparations for the start of the breeding season in April."
For more information on the fisheries, details of on-site tuition, equipment sales and hire and competitions, contact the Swinsty fishing office on 01943 880658 or visit yorkshirewater.com/recreation