English: Video released by: Natural Resources Wales / Cyfoeth Naturiol Cymru; 2018.

We've been rearing crayfish here at Cynrig hatchery for the last nearly 10 years now – so the white clawed crayfish, our native crayfish.

What we’ve done is we take buried females from the wild on an annual basis - that’s the egg laden females - bring them back to the hatchery and hatch the eggs in a controlled condition in re-circulated units.

The reason for that is that in the wild you’re looking at 5% or less survival, whereas here in the hatchery, we can get in excess of 70%, sometimes in excess of 80% survival.

What we do then is we’ll grow those juveniles to maybe 12 months of age at the earliest or sometimes a bit older, maybe 18 months, maybe pushing 2 years and we release those into specially selected “ark” sites.

These ark sites we’re choosing to safeguard the species, they’ve got to be discreet from any possible Signal populations and need to be above impassable barriers – maybe discreet still water bodies.

We’re looking at the water quality of these sites – it needs to be pristine, and crayfish are a really good indicator species for water quality. If you’ve got crayfish in your stream you know your water quality is pretty good.

In 2018, we've been back and surveyed a number of release sites, on the Wye catchment and we initially introduced juveniles there in 2012/ 13 and 14. So we went back in 2017 and found subsequently, those original animals in situ, but this year was the first year we’ve found first generation wild juveniles, so we’ve actually managed to establish a breeding population from introduced captive-bred animals.