|A European Eel. Image: Wikipedia|
Their rescue from two large tanks came after local councillor Jon Barry raised concerns about their fate as work progresses apace on the development of the site.
The site's developer agreed the eels should be rescued and brought in a boat to capture them.
The eels were then cleaned and released into the River Lune.
The tanks will now be decontaminated, drained, removed and the holes backfilled with clean material as part of ongoing work to prepare the site for building works.
The European eel (Anguilla anguilla) is classified as Critically Endangered by the IUCN Red List of Threatened Species, which is believed to have declined by up to 95 per cent over the last 25-30 years across Europe.
The Zoological Society of London says the reasons for its decline appear to be down to a combination of habitat loss, barriers to migration, parasites, pollution, over-fishing and climate change affecting oceanic currents.
(Living in two rusty tanks wouldn't have helped their chances, either).
"I'm extremely glad that the eels have been rescued," says Jon. "It wold have been awful if they had been buried alive and I am grateful that they have been released unharmed. Hopefully these 40 eels can help in the UK eel recovery!"