Milestone for Croatian Adriatic biodiversity with breakthrough in breeding Noble Pen shells

(Photo: Hectonichus/CC BY-SA 3.0)

Noble pen shells, a critically endangered species, have recently shown promising signs of recovery thanks to groundbreaking efforts at Aquarium Pula in Croatia.

For the first time, researchers have successfully fertilised their eggs in controlled conditions, marking a major milestone in the fight to preserve this rare species and protect the biodiversity of the Adriatic Sea.

Excellent news for the Adriatic Sea and Croatia’s biodiversity comes from Aquarium Pula, where this week, noble pen shell eggs were successfully fertilised, N1 reported.

This is a significant achievement, considering that noble pen shells have never been cultivated before, and little is known about their life cycle.

Three of the six adult specimens released a large quantity of eggs, measuring 40 to 50 microns, for the first time on Thursday, 19th September.

The eggs were then transferred to tanks housing other noble pen shells to encourage the release of male gametes.

Nobel pen shell (Photo: Hectonichus/CC BY-SA 3.0)

By the next day, aquarium staff had already observed fertilised eggs, whose development will now be closely monitored.

Aquarium experts explain that noble pen shells are hermaphrodites, reaching sexual maturity between their first and second year of life, or when they grow to about 10 cm in length. In the wild, they begin to spawn in late spring as the sea warms.

(Photo: Hectonichus/CC BY-SA 3.0)

To replicate these conditions, the aquarium in Pula has been gradually raising the water temperature by 1°C per week. The release of gametes was recorded at a temperature of 24°C.