The breeding of Patella depressa was studied at Trevone, North Cornwall, for 4 years. Gonads were examined and assessed by methods described in a previous report on P. vulgata.

In contrast to the common Limpet, P. depressa is a summer breeder in Cornwall. Gonad development begins in the spring and is complete by June or July. Spawning coincides with maximum air temperatures in July, August or early September. The autumn and winter period is passed with gonads in recognizable post-spawning and spent stages, and only a small proportion of completely resting neuter gonads is found in the early spring.

Mass spawning takes place, and gametes are voided rapidly. No definite spawning stimulus can be shown, but, as with P. vulgata, there may be some relation between onset of spawning and the occurrence of wave action on the shore.

The differences in breeding behaviour of P. depressa and P. vulgata reinforce the other differences between them and throw some doubt on the concept of super-species in Patella.