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Strange
creatures from the deep
Feature
April
2, 2003
 Prickly Shark
(Echinorhinus cookei)
A male Prickly Shark
(Echinorhinus cookei) of about 60 kg and 1.6m body length has just been brought into Townsville by fisherman Warren Williams of the FV "Merlin". It was tangled in a bottom-set longline at 500m depth, somewhere far off-shore of
Townsville, in north Queensland. The specimen was missing the upper lobe of its tail, probably bitten off and healed over to appear like a fish tail, causing Warren to ponder if he'd caught a "missing link" of some sort. Unlike the overall "sandpaper" feel of most sharks' skins, the specimen has surprisingly delicate slippery skin underlying the numerous sharp prickles. The teeth resemble a comb with sharp prongs bent sideways in both directions, and there is some speculation that it feeds by suction.
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Unlike other sharks, the dorsal fins are set way back near the tail, overlying broad ventral fins that appear wing-like in life.
The only previous Australian record of this sluggish, bottom-dwelling species is Victoria, according to CSIRO's "Sharks and Rays of Australia". Elsewhere in its global distribution the Prickly Shark grows to about 3 metres and is found near submarine canyons to
900 metres depth -- but sometimes ventures into shallow water.
The Prickly Shark is the second of only two species in the family of Bramble Sharks
(Echinorhinidae), and the other species has a liver oil once highly prized in Namibia for its medicinal properties.
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Prickly
Shark tooth in upper jaw
Underside
of head
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This specimen is amongst a batch of unfamiliar deepwater fishes brought in to AIMS in recent years by the
FV "Merlin". These fish include species not found in any Australian fish identification books, such as the 50 cm Pacific Beardfish
(Polymixia berndti) and 65cm Pacific Driftfish (Ariomma
evermani), and the Tang Snapper (Lipocheilus
carnolabrum) recorded previously only from Western Australian waters. AIMS researchers had to consult Japanese and South African books to provide preliminary identifications, and the sizes of the Australian specimens generally far exceeded the overseas reports.
Overall, the new fish records suggest the occurrence of a Pacific-wide deep-water fish fauna that extends to our very deep continental slope waters off the Great Barrier Reef. This ecosystem is very poorly studied, but contains many large-eyed, active fish of large size, including the commercially valuable Ruby and Rosy Snappers (genus
Etelis ) and Rosy Jobfish and Goldband Snappers (genus
Pristipomoides) of the Family
Lutjanidae.
| The pictures
(right) of the Pacific Driftfish show its large eyes, deeply forked tail, finlets and muscular body adapted to rapid swimming in the dark pelagic environment of the deep tropical sea. It has a surprisingly small, delicate mouth with tiny teeth, suggesting a large proportion of gelatinous plankton in its diet, such as
salps. Indeed, the general appearance of this fish gives a similar impression to the vast schools of small planktivorous fusiliers (Family
Caesionidae) that swarm through coral reef edges.
The Tang Snapper
(below right) has large fleshy lips and large sharp teeth, and is a surprisingly bright yellow colour given its capture depth of around 300 metres. It bears a slight resemblance to both the Red Emperor
(Lutjanus sebae) and Spangled Emperor (Lethrinus
nebulosus) found in the Great Barrier Reef fishery. Consequently, a few other Queensland fishermen have called it "Yellow Emperor" in the rare occasions they have caught it, introducing yet more confusion amongst the various common fish names up and down the Queensland coast.
Tang
Snapper |
Pacific
Driftfish
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The new specimens will be despatched to the CSIRO collection in Hobart, and Museums for curation and positive identification. More information can be directly accessed at:
 Fishbase.org
and
Elasmobranch
research
at Monterey Bay
Image
of a live Prickly Shark
Prickly
Shark Echinorhinus cookei photo courtesy
of Elasmobranch research, Monterey Bay.
For more information
contact
Mike Cappo, AIMS
Phone: 07 47534262
Email: m.cappo@aims.gov.au
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20030402 20060410