Pear limpet (Scutellastra cochlear)

Previously known as Patella cochlear, or cochlear limpet.

Distinctively pear-shaped, often encrusted by coralline algae. Inner surface white, tinged blue and often mottled with black. Muscle scar is U-shaped and black.

Around 50 mm. Large specimens may exceed 70 mm.

Lives in dense colonies low on exposed rocky shores, forming the so-called ‘cochlear zone’, from the mouth of the Orange River and across the Cape Province to Durban, South Africa. Very slow-growing, with a life span of 25 years. Associated with a paint-like coralline alga, Spongites yendoi, which it grazes. Narrow gardens of fast-growing fine red algae fringe and sustain larger individuals, and are territorially defended and fertilized by the limpets.

Two Oceans: A Guide to the Marine Life of Southern Africa (2007)

Distribution & Life History Traits

Scutellastra cochlear is a locally abundant species forming prominent dense colonies low on the shore and prefers exposed shores with strong wave motion. Each individual establishes a limpet scar on the rock surface and occupies the same position throughout its life. Juveniles commonly establish on the shells of adult limpets until they are large enough to establish their own limpet scar.

Scutellastra cochlear primarily feeds on the coralline algae Spongites yendoi. Pear limpets are known to farm S. yendoi in algal gardens around the limpet scar and to actively protect these gardens territorially against any intruder. The limpet-algae relationship may be mutualistic : Scutellastra cochlear excludes other algal species from the shore to favour S. yendoi, and the limpet excretions provide additional nitrogen for the algae, increasing its productivity.