Monday, December 15, 2014

Sea Creatures

On the third level of the Crary Lab, ichthyologists (scientists that study fish) have set up research aquarium facilities that includes a "touch tank". You are allowed to carefully put your hand in this tank and touch some of the creatures. The water in the tank is from McMurdo Sound - naturally it is very cold and keeping your hand in there is only possible for short periods. Some of the photos are taken looking through the water so they may seem a bit fuzzy.

The research aquarium in the Crary Lab

A pink sea urchin

The underside of a sea star and an all white sea slug.
The orange and white creature is a sea anemone. The all white item is a sea slug

Sea slugs are shell-less molluscks. Their scientific name, Nudibranchia, means naked gills; it describes the feathery gills and horns that are on their back.

Another species of sea anemone, with white tentacles, can be seen in this picture.

There are various species of sea anemones in Antarctic waters. They are predatory and can feed upon pencil sea urchins, sea stars and occasionally jellyfish which get close enough to the sea floor

Rockcod have adapted to the low and stable temperatures of sea water in McMurdo Sound, which is almost constantly at -1.86C (28.65F). They live on the sea floor, feeding on prey by ambush or hunt-and-peck feeding.

The yellow balloon looking creature is a lamellarian gastropod. They range from about 1.5 to 7cm (0.6 to 2.75 inches) long. The gastropod does not have a shell for protection but it appears to be protected by emitting a chemical that deters predators.

In this picture you can see the pink upper side of the sea stars as well as their under side.

The pink sea stars (Odontaster validus), which can also be cream coloured, is the most abundant sea star in the shallow waters (15-200m) around Antarctica. They are extremely slow growing, taking bout 9 years to reach 30grams (~1oz) wet weight. Based on observed growth rates, it is believed that sea stars can live to be over 100 years in age. They can sense light and dark in "eyes" that are found at the end of each arm. This sea star feeds by inverting its stomach to engulf and digest prey. The sea stars feel like a cushion covered with mild sand paper.

This isopod looks brown and hairy! It's only about 10cm (4 inches) long.

Isopods of the species shown above (Glyptonotus antarcticus) can grow to be up to 20cm (7.9inches) long. They are omnivorous and will eat whatever it can find, including small Isopods of its own species - yes, cannibalism!). They prefer darker periods and are considered nocturnal, hunting for food at night. This isopod species must feed twice a week to stay healthy.

A video of some sea spiders is best viewed at this link 


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