To improve the welfare of captive animals and to ensure they are demonstrating natural behaviours, it is important that we understand how they act in the wild.
The small spotted catshark, Scyliorhinus canicula, is a common aquarium shark species that has some very interesting social interactions. Female catsharks actively segregate themselves from males to avoid sexual harassment, spending more time in shallower, warmer waters, hidden in refuges at a detriment to their energy budgeting. Therefore in terms of keeping the small spotted catsharks in aquariums, aquarists should ensure they are being kept in single sex groups, or if in mixed groups then refuges should be provided allowing the females to hide from the males. It should also be understood that in mixed groups the males will be active throughout the day while the females will mainly be nocturnal.
Housing small spotted catsharks in mixed groups could increase the stress levels of the females, especially if no refuges are provided.
More information on catshark behaviour can be found from the paper:
Wearmouth, V.J., Southall, E.J., Morritt, D., Thompson, R.C., Cuthill, I.C., Partridge, J.C., & Sims, D.W. (2012). Year-round sexual harassment as a behavioural mediator of vertebrate population dynamics. Ecological Monographs, 82(3), 351-366.