Aquarists at Bristol Aquarium are hoping to hear the splash of tiny fins after a rare type of ray began laying dozens of egg-cases.

The Harbourside aquarium is home to three undulate rays which are part of a new captive breeding programme for the officially Endangered species.

So far the female has laid around 50 eggs which are now being cared for in the aquarium’s quarantine area, and aquarists are hopeful some of them will be fertile.

Found throughout European waters, the undulate ray can grow up to 100cm in length, live for around 20 years and is known for the striking patterns on its back.

It was officially declared ‘Endangered’ in the IUCN Red List of Threatened Species in 2008 which means it faces a very high risk of extinction in the near future.

In 2007 the fish was included in the UK Biodiversity Action Plan and in 2009 it received full protection from the European Council meaning that it cannot be retained or landed if accidentally caught by fishermen.

The undulate ray is oviparous, which means that it lays eggs, and it has been known to produce huge numbers of them. One specimen was recorded as having laid no fewer than 88 eggs over a 77-day period.

Bristol Aquarium’s Dan de Castro said: “Many species of European sharks and rays are increasingly coming under threat of extinction in the wild. It would be great if we were able to successfully breed this particular species in captivity and we are closely monitoring the egg-cases for signs of life,” he added.

The eggs, which are often washed up empty on beaches and known as mermaids’ purses, take around seven months to hatch.

Also known as the painted ray, the undulate ray is one of the most distinctive rays to be found in UK water. This species is patterned with long, wavy, dark lines edged with white spots that run parallel to the wing margins.

Rays belong to the same family as sharks and are effectively ‘flattened-out’ versions of their close cousins. UK waters are home to at least 15 different species including the electric ray and the common skate, which can reach lengths of up to three metres.

Issued by Bristol Aquarium. For more information and to arrange interviews and picture opportunities please contact Tina Patel and David Waines on 0117 934 0944 or Dan de Castro on 0117 934 0943.