Black Limpet

Lottia asmi

Lottia asmi is a small limpet that typically reaches a length of 10 mm and a height of 8 mm. Its exterior is smooth and can appear worn, often displaying fine radial ridges near the margin. The coloration is generally brownish or greyish-black on the outside, while the interior is black, sometimes featuring a pale band along the edge. This species is primarily found in the northeastern Pacific Ocean, ranging from southern Alaska to the Revillagigedo Islands in Mexico. It inhabits the intertidal zone and is often seen on the shells of black turban snails, California mussels, and occasionally on rocks or sponges. Most encounters occur at depths shallower than 40 meters, with a significant number found under 10 meters. As a herbivore, the black limpet feeds on microalgae that grow on the surfaces of its host shells. It is known to switch hosts at low tide, particularly when turban shells are aggregated. Juveniles mature in about eight months, and reproduction occurs intermittently throughout the year, with notable spawning events in March, October, and a prolonged period in mid-summer. The larvae develop through a planktonic phase before settling and transforming into the adult conical shape. Divers may encounter the black limpet in tide pools or on rocky substrates, often camouflaged against their surroundings. Observing their grazing behavior on host shells can be an interesting highlight during a dive. The species has not been evaluated by the IUCN, leaving its conservation status uncertain.