Both species are oviparous, meaning they reproduce by laying eggs. Females produce leathery, yellowish-brown egg cases—usually in pairs—commonly referred to as “mermaid’s purses”. These egg cases have curly tendrils that allow the female to securely attach them to seaweed or other structures on the seabed. Within the egg case, the developing shark feeds on the yolk until it is fully absorbed, a process that takes approximately six to eight months. Once development is complete, the juvenile is strong enough to hatch and swim away independently. Because this reproductive process occurs externally to the female’s body, it provides a unique opportunity for conservation intervention. This is what enables Sharklab Malta, a local NGO dedicated to the conservation of sharks and rays, to rescue and successfully rear tens of sharks each year from egg cases recovered at fish markets.

The small-spotted catshark and the nursehound face similar threats in the Mediterranean Sea. Both are highly susceptible to bycatch in commercial fishing gear, ingestion of plastic litter due to their benthic behaviour, habitat degradation, and the impacts of ocean warming and acidification, which can reduce embryonic growth and survival rates. Additionally, targeted fishing in certain regions further pressures their populations.