Molluscs

Crabs, shellfish, clams,...

An abalone receiving an ultrasound at UC Davis Bodega Marine Laboratory
An abalone receiving an ultrasound at UC Davis Bodega Marine Laboratory

Ultrasound used to determine if abalone about to reproduce

Scientists at the University of California, Davis, are using ultrasound to find out whether abalone are ready to reproduce.

This non-invasive, no-contact method is kinder than the normal method of getting the info, which involves having to pry them off the surface they are suctioned upon.

Joanna Griffiths discovered that selective breeding in hatchery management practices may help to increase resiliency for low salinity for eastern oysters.
Joanna Griffiths discovered that selective breeding in hatchery management practices may help to increase resiliency for low salinity for eastern oysters.

Resilience pays off in oyster research

Researchers led by Louisiana State University (LSU) alumna Joanna Griffiths from Portland, Oregon, and her faculty advisor LSU Department of Biological Sciences Associate Professor Morgan Kelly reveals why some oysters may be more resilient to freshwater than others. 

Griffiths wanted to find out whether, due to transgenerational plasticity, oysters that lived in low salinity would have offspring that was more resistant to low salinity.

Transgenerational plasticity occurs when a generation’s flexibility is passed on to the next generation.

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.

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.

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.

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.