Molluscs

Crabs, shellfish, clams,...

One of the common cuttlefish in the Marine Resources Center at the Marine Biological Laboratory
One of the common cuttlefish in the Marine Resources Center at the Marine Biological Laboratory

Cuttlefish smart enough to wait for better reward

Using a modified version of the Stanford marshmallow test, researchers at the Marine Biological Laboratory (The University of Chicago) discovered that cuttlefish had the ability to delay gratification for a better reward—and those that were able to do it for a longer duration possessed better cognitive learning abilities.

The findings, which demonstrated the link between self-control and intelligence, was published recently in the Proceedings of the Royal Society B journal.

Close-up of oyster bed
Close-up of oyster bed

Why restore Hong Kong's lost oyster reefs?

Research jointly conducted by The Swire Institute of Marine Science (SWIMS), Faculty of Science, The University of Hong Kong (HKU), and The Nature Conservancy (TNC) emphasises the importance of oyster reefs in mitigating some problems associated with coastal development, like storm-surge damage and biodiversity loss.

Clam lived to be over 500 years old

This makes the otherwise unassuming Arctica islandica clam the longest lived animal species on record, though some corals are probably much older. The clam was initially named Ming by Sunday Times journalists, in reference to the Ming dynasty, during which it was born.

Researchers from Bangor University in North Wales – unaware of the animal’s impressive age – determined the age by drilling through and counting rings on its shell (a technique known as sclerochronology). In the process the clam died.

Shipworm: The Scourge of Wooden Wrecks is Really a Mussel

A specimen of shipworm (USGS / Wikimedia Commons / Public Domain)

Have you ever wondered why some bodies of water, such as the Baltic, have so many wooden wrecks in great condition while other areas have almost no wooden wrecks at all? It has something to do with salinity; however, it is not the salt in seawater that consumes the wrecks but a mussel, which somewhat confusingly is called a worm—and it only lives in saltwater.

Antarctic sea snail. To build up their shells, these animals extract raw materials from the seawater in a process called biomineralisation.

Why sea shells vary in size across different regions

Seashells come in various shapes and sizes. And it appears that the seashells from the tropics tend to be larger than those found in the temperate regions.

Far from being just a coincidence, it seems that there is a rational explanation for it. Simply put, this is because the sea snails in the tropics have to devote relatively less energy to shell growth, compared to those in the cold-water regions.

AIMS' Dr Cherie Motti, beside a tank housing a Pacific triton sea snail.
AIMS' Dr Cherie Motti, beside a tank housing a Pacific triton sea snail.

Great Barrier Reef's saviour—a giant snail?

A giant sea snail may turn out to be another line of defense against the destructive crown-of-thorn starfish that is currently plaguing Australia’s Great Barrier Reef.

Called the Pacific triton sea snail (Charonia tritonis), it can grow up to about 50 to 60cm and is indigenous to Australian waters. More importantly, the crown-of-thorn starfish happens to be part of its natural diet. However, the sea snail is currently endangered due to the consumer demand for their shells.

Giant Australian Cuttlefish

The giant Australian cuttlefish (Sepia apama) is the largest cuttlefish in the world, reaching up to half a metre in total length and weighing in at around 11kg. Solitary animals, they are found all along the coastline of the southern half of Australia—from Central Queensland on the eastern coast, right around the bottom of the continent and up to Ningaloo Reef in Western Australia.

Cuttlefish are capable of changing colour and pattern (including the polarization of the reflected light as well as the texture of the skin.

Cuttlefish can go into electric stealth mode

Sharks home in on faint bioelectric fields generated by the bodies of their prey which they pick up using sensitive detectors on their snouts.

When researchers from Duke University showed captive cuttlefish held in a tank videos depicting the menacing silhouettes of a shark or predatory grouper fish they reacted by lowering the electric field dramatically. Being shown the shadow of a harmless crab produced no reaction.

Blue mussels, edulis mytilus, are effective filter feeders

Blue mussel beds can clean fjords and bays

A project conducted by researchers from Denmark's Technical University showed that 18 hectares of blue mussels in Skive Fjord reduced the levels of algae low enough to prevent oxygen depletion.

The main issue with fertilization of coastal waters causing algae bloom stems from the massive amounts of dead algae sinking to the bottom in thick layers. As they rot, they consume and deplete oxygen, choking huge swathes of the seabed, leading to widespread bottom death. This is a big issue along coasts of agricultural areas.