Aquarium baby boom for sharks

Coral tree covered in shark egg-cases at Tynemouth's Blue Reef Aquarium.
Coral tree covered in shark egg-cases at Tynemouth's Blue Reef Aquarium.
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A BABY boom is taking place in Tynemouth – among a collection of sharks.

Last month alone, 26 dogfish egg-cases were collected at the Blue Reef Aquarium’s rockpool displays and transferred to a series of special ‘shark nurseries’.

By using special lighting, the egg-cases are illuminated in their nursery display enabling visitors to watch the baby sharks wriggling in their semi-transparent egg cases.

Aquarist Lauren Lawson said: “It’s fascinating to watch the tiny shark embryos developing inside their egg-cases.

“As they get closer to hatching you can clearly see them starting to actively try to find a way out of the leathery eggs.

“Once they do finally emerge they are pretty much fully formed miniature versions of their parents.

“The only real difference is they do not have to be fed quite as much as they get all their nourishment from their attached yolk sacs.”

Young dogfish are about 10cm long when they eventually hatch after spending up to 11 months developing inside the egg capsule.

Each capsule is usually secured to rocks or seaweed by tendrils which prevent it from being washed away by tides or currents.

Once the sharks have hatched the empty egg-cases – commonly known as mermaids’ purses – are often found washed ashore on British beaches.

The dogfish, or rock salmon as it is sometimes called, can reach lengths of up to a metre when fully grown and is an important species for commercial fishermen.