Blackpool aquarium finds evidence of hidden shark Published duration 19 May 2011

image caption Staff now have to find the carpet shark which laid the eggs

Aquarium staff at a Lancashire attraction have discovered evidence that a shark they did not know they had has been lying undetected in a tank.

Staff at Blackpool's Sea Life Centre were baffled when two shark eggs were found in a tank which held other sharks who only give birth to live young.

It is thought a former curator may have placed a small tropical carpet shark in the display and not recorded the fact.

The shark may have been hiding in the tank's seabed to avoid other predators.

'Get some babies'

"When we found the first egg during a routine dive in the ocean tank just before Easter, we initially thought it must be artificial, and part of the tank's theming decor," said senior aquarist Martin Sutcliffe.

"We were all completely baffled when we took a closer look and realised it was real, and then we found another one about three weeks later."

Sea Life's veterinary consultant and fish specialist Sue Thornton confirmed that the four-inch-long (10.16cm) eggs come from a carpet shark - a family so-called because of their habit of lying static on the seabed.

Mr Sutcliffe added: "The ocean tank is a massive half-a-million litre display with numerous dark nooks and crannies amongst the theming, and it is just feasible that a small shark could have stayed hidden.

'Feel threatened'

"A small carpet shark would possibly feel threatened by the larger sharks in the tank, which is the only explanation we can come up with for it keeping out of sight for so long.

image caption The carpet shark eggs are about four inches (10.16cm) long

"Ideally, we would like to move her to a smaller tropical tank and provide her with a mate.

"The sudden appearance of these eggs suggests she has reached maturity and if we partnered her with a mature male there's every chance we would get some babies."

Along with hundreds of colourful shoaling fish, the Sea Life tank features a bowmouth shark plus sandbar, nurse, black-tipped and white-tipped reef sharks - all of which produce free-swimming offspring.