Organism

During winter, large numbers of orange roughy move to the seamounts to spawn. During this time, they have been caught in huge amounts in trawl nets of the Australian and New Zealand coasts and are

Little is known about orange roughy predators but they probably include many deep sea fish and sharks. These fish live at great depth and are very active and fast-moving compared to other species at the same depths, so they may be able to avoid many predators.

The jewel squid’s left eye is always much larger than its right. In some species the left eye is telescopic while the smaller right eye is normal. Their name comes from the scattering of small glittering spots over the undersides of the body, head and arms like tiny car headlights.

When the squid is hanging at a 45 ° angle, all these light organs aim down and produce just enough light to cancel out the silhouette of the squid against the weak light from the surface above. They can even adjust the lights for different depths or time of day.

Lighthouse fish
Phosichthys argenteus

This is found in deep subtropical waters of all oceans, from depths of 500 to 2,000 m. Its length is between 10 and 30 cm. They are bioluminescent fishes, possessing rows of photophores along their sides, with which they hunt planktonic invertebrates, especially krill.

The species occurs in temperate marine waters of the southern hemisphere, except off South America. In Australia it has been trawled from off New South Wales, Victoria, Tasmania, South Australia and Western Australia.

They are generally scavengers eating the remains of dead fish and other marine animals that sink to the ocean floor. They have also been found to eat animals that may not have been dead when swallowed. Perhaps they found an old or sick animal or they may have just been lucky. Unless you can study these communities for many, many years you will never fully understand all the relationships.

The firefly squid is also capable of emitting light from its entire body from another set of light-producing organs.

The Viperfish has large wide jaws with huge fang-like teeth. They can unhinge their upper jaw to allow them to swallow prey similar in size to themselves.

The sides of its body are covered with coloured areas, each with one or more small light-producing organs. During the day they are found in deep water but at night these fish swim up into water less than 600m depth where there is more food.

Like the Orange roughy they are much more active than most fish found at these depths.

The lantern fish is another deep-sea fish that has small light-producing organs on the underside of their body. Special cells that glow with a green light make the light. Predatory fish swimming below them find it difficult to see their glowing bodies looking into the light above.

Some closely-related species of lantern fish also have pairs of light organs situated directly in front of the eyes that act like flashlights and light up would be prey,

The front pair of legs is like long, fine tweezers, and may be used to locate and capture food. When they hatch they join the deep-sea plankton before changing into a small spherical juvenile form. They look so different from the adults that in the 1800’s they were thought to be different type of crustacean in their own family.

Salps are jelly-like, almost transparent barrel-shaped marine animals that live in the plankton. They vary in size from a few millimetres at their birth and grow up to about 10cm.

Salps filter food particles from seawater by pumping it in from the mouth and out through the rear opening using muscle contractions. This pumping action causes the salp to move forward so they swim and feed at the same time.

Salps are the main diet of several fish species, but have also been found in the stomach of albatross and seals especially when other food sources are scarce.

Shrimp are only one group of the Crustaceans. Crustaceans, from microscopic forms found in plankton to large crabs and crays, are one of the most important and abundant groups of animals in the sea.

Plankton form the lower link in most marine food chains. The Phytoplankton use energy from the sun to produce food through photosynthesis, then they are eaten by Zooplankton which are eaten by small fish and so on up the food chain.

Dead organisms from plankton and fragments of larger ones clump together and slowly sink taking nutrients to the ocean floor. Again many animals can obtain their energy from this “marine snow”.