Molluscs

Crabs, shellfish, clams,...

The Sap-sucking Sea Slug: Butterfly Sacoglossan

Cyerce sp. sacoglossan sea slug, or butterfly sap-sucking slug, Green Island, Taitung, Taiwan.
Cyerce sp. sacoglossan sea slug, or butterfly sap-sucking slug, Green Island, Taitung, Taiwan.

Many divers, and especially macro underwater photographers, adore the lovely, colorful, and photogenic sea slugs found in the deep. We often call them nudibranchs, the “butterflies of the sea.” But not all sea slugs are nudibranchs. Have you ever heard of the sacoglossan? Underwater photographer Wesley Oosthuizen takes a closer look at a special sacoglossan species—the butterfly sap-sucking slug.

Kellet's whelk laying egg capsules
Kellet's whelk laying egg capsules

How higher temperatures affect whelk larvae

For the most part, most research have focussed on the impact of oceanic temperature changes on adult animals, but few looked at the animals' early life stages. A study by researchers from the University of California, Santa Barbara gives a useful insight into this specific area. 

Focussing on the larvae of the Kellet's whelk, a common sea snail in Southern California, it showed that rising temperatures will adversely impact the larvae. 

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.