The small-spotted catshark has internal fertilization and lays egg cases from January to July. These golden-coloured cases are oblong in shape and measure around 5-6 cm in length. At each corner of the egg case is a thread or tendril which it winds around algae, for example, to keep the egg case in place for the 5-11 months it takes for the shark to hatch.
Did you also know that the small-spotted catshark is nocturnal? It is common along the entire Norwegian coast south of Troms, but most common up to Trondheim. You will find them sleeping on the seabed during the day.