Top Snails (Norrisia norrisii)


Top snails  (gastropods) originally named in 1838 trochiscus norrisii  are a real treat and regular attraction found on our guided dives and Snorkel tours in San Diego’s La Jolla Cove Ecological Reserve.  The gastropods are found on the US Pacific coast from Monterey to the Baja peninsula.  

The fleshy foot of the snail is a bright reddish orange with a black speckling lining .  The beautiful orange coloration of the foot is spectacular under illumination from a divers light.  Most divers miss this little beauty clinging to the frond or stipe of the kelp because they do not carry a light with them even during the day dives.  When dead their shells can be found on the sea floor and they are beautiful but often occupied by hermit crabs.

They feed on Giant Kelp (primary food source) and then Feather Boa (secondary food source) and lastly the Sea Palm Eisenia aborea.  

Things eating Topsails include Sea Otters, starfish like Pisaster, Spiny lobsters, drilling mollusks, octopus, and moon snails. They will flee predators by detaching themselves and falling to the bottom sometimes rolling away to safety down slope.  Mortality is much greater on the bottom than much higher in the giant kelp or other alga.

Little is known about the reproduction cycle.  The may be free or broadcast spawning or possibly internally fertilize eggs.