Two Oceans Aquarium Volunteer Manual – Module 3 – INVERTEBRATES 49 Tiger Cowrie COWRIES Habitat Coral reefs and beyond the lowest level of low tide. There are some temperate species in our region on the South coast. Description Colourful shiny egg-shaped shells. Operculum absent. The cowrie not only protrudes its mouth and tentacles, but also its mantle which extends right over its shell completely obscuring it and giving it the brilliant gloss so prized by shell collectors. Feeding Most of them browse on sponges. Predators Some species of fish. Did you know? Until recently, the Fulton’s cowrie, Cyprea fultoni’s, was only found in the stomach of the black musselcraker (Poenskop). As such, it was considered as extremely rare and was the most expensive cowrie in the world.
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COWRIES - Two Oceans Aquarium€¦ · COWRIES Habitat Coral reefs and beyond the lowest level of low tide. ... most expensive cowrie in the world. 50 Two Oceans Aquarium Volunteer
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Coral reefs and beyond the lowest level of low tide. There are some temperate species in our region on the South coast.
Description
Colourful shiny egg-shaped shells.
Operculum absent.
The cowrie not only protrudes its mouth and tentacles, but also its mantle which extends right over its shell completely obscuring it and giving it the brilliant gloss so prized by shell collectors.
Feeding Most of them browse on sponges.
Predators
Some species of fish.
Did you know?
Until recently, the Fulton’s cowrie, Cyprea fultoni’s, was only found in the stomach of the black musselcraker (Poenskop). As such, it was considered as extremely rare and was the most expensive cowrie in the world.
One mussel can pump as much as two litres of water every hour.
Because mussels are filter feeders, they can concentrate pollutants and toxins in their flesh. They should not be collected for food if they are near a city.
CLASS: BIVALVIA
CLAMS, MUSSELS AND OYSTERS
Habitat Bivalves have a diversity of habitats. Some are attached to rocks in the lower balanoid zone where the waves break at low tide. Some species burrow into sand or mud.
Description of Black or Brown Mussels
They have streamlined shells made up of two close-fitting halves.
The two shells snap together using a strong ligament and they are very hard to pull apart once closed.
The shells are anchored to the rocks by strong byssus threads.
On the rocks a great many individual mussels group together to form mussel beds.
The largest part of the animal is the gonad (its reproductive organ).
Feeding Filter the water for minute particles of food (plankton).
Predators Many fish with strong jaws feed on them, as well as lobsters, spiny starfish and octopus. The kelp gull also preys on mussels.
CHARACTERISTICS
All species in this class have two shells enclosing the body.
Body compressed from side to side.
They have gills with cilia around the inner edge of the shell to propel water into the shell.
Lack head with tentacles, eyes and ribbon tongue (radula).
Once detached from the rock, it rolls up to protect the softer body parts. This reflex action prevents damage should the chiton be rolled around by the waves.
The giant chiton, Dinoplax gigas serves as excellent bait for white musselcracker.
CLASS: POLYPLACOPHORA
CHITONS
Habitat Some on underside of rocks, others on exposed rock surface and the giant chiton partially or totally buried in sand on flat rocky reefs.
Description
Oval, flattened mollusc.
Eight, overlapping articulated plates along the back which can flex the body over the surface
Plates surrounded by a tough leathery girdle.
Head completely hidden beneath the girdle and lacks eyes in most.
Remainder of the underside – broad muscular foot rimmed with small gills.
Feeding
When active they creep slowly about, rasping encrusting plants or animals from the rock surface with their powerful file-like radula.
Predators Any predator that is able to dislodge them from the rocks, e.g. seabirds, fish, crabs, eats chitons.