Deep sea animals

25 October, 2010

BlackSeadevilMelanocetusniger
Black Seadevil, Melanocetus niger.
Image: Julian Partridge & Camilla Sharkey
Source: Julian Partridge & Camilla Sharkey

MV senior collections manager and fish specialist, Dianne Bray, recently brought back extraordinary deep sea creatures from a three-week expedition to the south-east Pacific Ocean off Peru and Chile.

She joined an international team of biologists investigating the bioluminescence and sensory systems of animals found in the Peru-Chile Trench, including those living in the midwaters of the twilight zone between 150-200 and 1000 metres, and the scavenging fauna found at the bottom of the trench. The team, including scientists from Australia, Germany, UK, Japan, USA and NZ, used specialised sampling and collecting equipment to gather images and specimens.

Food is scarce in the deep sea and many animals are remarkably adapted to find a meal without being eaten themselves. Many species undertake daily migrations to feed at night in the upper 200 metres where food is more plentiful, returning to hide in the deep dark waters during daylight hours. Bioluminescence is the major source of light and is used by animals to hide their silhouette, to attract prey, to illuminate prey and for species recognition.

Most deep sea animals are very fragile and easily damaged when caught in most research and commercial fishing nets. The expedition’s trawl nets, developed at the University of Queensland and the Harbor Branch Oceanographic Institute in the US, have been designed to collect deep sea animals very carefully and bring them to the surface very slowly, ensuring the specimens are alive and in good condition.

Some researchers aboard were studying the visual systems of fishes and cephalopods that live in the dim light of the deep ocean, while others were looking at lateral-line systems that are often well-developed in deep sea fishes and can detect movement and vibration in the surrounding water. Another team was working on the genes that drive the daily biological rhythms of deep sea animals. On five occasions, a benthic lander with a baited deep sea video camera and baited traps was deployed to the bottom of the trench to film and collect scavenging animals living on the sea floor to depths of more than eight kilometres.

 Di brought back some amazing animals for Museum Victoria’s research collections, including a gulper eel, deep sea angler fishes, and many stunningly beautiful invertebrates, such as vivid red shrimps and cephalopods. She also brought back an amphipod crustacean collected from seven kilometres below the surface. These animals survive by scavenging on animals that die and fall to the ocean floor. The expedition uncovered many species that are new to science.

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gaby 8 November, 2012 16:44
what do they eat?
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Image Gallery

The Black-belly Dragonfish Fishes at the bottom of the trench. Jellyfish a mesopelagic amphipod Retrieving the midwater trawl The scavenging amphipod Eurythenes seed shrimp Whipnose Anglerfish Bioluminsecent lure of Whipnose Anglerfish

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