They spend the spring, summer, and fall in rocky subtidal areas, but winter in deeper offshore waters due to the strong currents at that time of year.

Redspotted catsharks range in length from 30 to 66 cm, although these sizes are taken from captured sharks, and it is believed that they may grow larger than this.

There are no known predators to the catshark, although juveniles typically spend their early life in the deeper offshore waters.

The paucity of ovigerous females during fall probably indicates that eggs were laid during summer, when massive depositions of egg-cases occurred on fronds of the subtidal brown kelp 'Lessonia trabeculata'.

Their primary food sources are various species of crabs and the rhynchocinetid rock shrimp Rhynchocinetes typus.

These differences are most probably an effect of higher prey diversity associated with microhabitats generated by kelp forests that allow sexual segregation of isotopic niche.

Therefore, extensive kelp harvest may cause significant effects in isotopic niche and nutritional status of adult redspotted catshark and may negatively affect its populations.

However, they mate seasonally, typically in spring and winter, though females have occasionally been shown to have egg capsules in the summer.

It is believed that juveniles swim into deeper waters in order to avoid predation in the sublittoral zone that they return to when they are adults.