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Long-wattled Ghost-shark colorized

By AlexSone
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Order: Wobbegongs (Orectolobiformes)
Family: Carpet sharks (Orectolobidae)
Habitat: Pacific Ocean, depth about 1500 – 2000 meters.

Sharks are highly adaptive creatures: this group of fishes is known from Devonian, having proved thus the abilities to adapt to various changes of environment. Opinion that sharks do not evolve till their history is deeply wrong. Various species, families and orders of these fishes replaced each other as regularly, as groups of sea mammals, for example. From most ancient times sharks aspired to take a place of supreme predators of ecosystems. It was possible to them for many times, but sharks had reached especial success in Cenozoic when requiem and mackerel sharks, the top of evolution of sharks, had appeared. The place at top of food pyramid is honourable, but too risky – at ecological crisis predators die out at first. At the boundary of Holocene and Neocene “charismatic” pelagic sharks dwelt at ocean had disappeared – schools of pelagic fishes served as food to them and their catch had died out. Their populations undermined by chasing of people gradually degraded. To early Neocene at the planet mainly medium-sized bottom-dwelling sharks survived. And they had given in Neocene a new wave of speciation. The majority of Neocene sharks are descendants of these species.
After ecological crisis and extinction of pelagic organisms sharks descending from shallow-water species developed the oceans anew. Among them there were species had mastered polar waters of Arctic Ocean and Subantarctic. And some sharks had started to storm ocean depths. Deep-water fauna depended on efficiency of ecosystems of top layers of water had suffered huge damage till the time of “plankton accident” at the boundary of epochs, therefore at early Neocene deep-water ecosystems had started to form practically from zero.
Among sharks occupied depths of ocean there is one descendant of carpet sharks, whose ancestors lived in shallow waters earlier. Obviously, ancestors of this fish had “moved down” to depths of ocean along the continental slope (obviously, somewhere in area of Australia or Indonesia). Therefrom this fish had passed to pelagic habit to life already as deep-water animal. Hence of fantastical appearance this fish named ghost shark. The length of this fish is about 2 meters; tail fin with much lengthened top blade located almost horizontally makes about one third of general length.
This fish lives in depths where change of day and night is not felt at all – at the depth over thousand meters. Colouring of skin of ghost shark is unicolor light grey; that’s why fish looks “belongig to the beyond”. As against overwhelming majority of Neocene sharks it is completely blind fish – even a sign of eyes is not remained from outside. Eyes are functionally replaced with another “secret weapon” especially advanced at sharks – instead of them organs of lateral line are used for orientation in water. Ghost shark has flat head, lengthened body and rather short fins. At this fish there are two back fins, on each back fin there is hollow corneous spike connected with poisonous gland. This is the main protective adaptation against deepwater predators: sometimes these sharks are attacked by squids and their own larger congeners.
Similarly to all carpet sharks the ghost shark has many skin outgrowths at the edge of muzzle. This inheritance from carpet sharks of shallow water habitats earlier serving for masking had got other function in gloom of depths, much more important for survival: very much advanced outgrowths on head contain branches of lateral line, and fish orientates with their help. Outgrowths on muzzle reach the length equal to fish’s head. It has determined the specific name of fish: “cirrhosissimus” means “the most whiskered”. Organs of lateral line located on outgrowths of fish’s head permit to trace the slightest changes of electric field surrounding fish, meaning presence of other live creatures.
Besides long-wattled ghost shark there is very keen sense of smell: it has large chinky nostrils.
This shark is slow: the most part of time it passively floats in thickness of water, tracking down other fishes and various pelagic invertebrates – squids and octopuses. Its catch not always differs in speed; therefore it may be easily caught even by such blind and slowly moving predator. Long-wattled ghost shark is able to catch fast catch, making short sharp throws. This fish eats basically fishes and squids having soft and flabby body consistence. Therefore its teeth have not cutting or crushing, but thrusting type – they are rather thin, awl-like and slightly bent. With the help of such teeth it is easy to catch slippery and soft-bodied prey. Having an opportunity, long-wattled ghost shark sometimes eats carrion – corpses of fishes and large sea animals immersed to the bottom. Eating carrion, the fish seizes sticking up parts of carcass and sharply turns, trying to tear off a piece. But more often this shark is interested not in carcass, but in animals coming to feed at it.
In typical case sharks lay large eggs from which the posterity hatches after rather long time. For the pelagic species living above the big depths, such vital strategy is unacceptable: females should make migrations to the continental slope to hatch posterity or to lay eggs right in water where they will fall to depth and can not develop there. The smaller number of sharks is live-bearing species, and long-wattled ghost shark belongs to their number. Pairing at this species occurs at any time of year – in ocean depths seasonal change are not expressed. Male is a little bit smaller than female (its length is about 170 cm), and has advanced copulating organs on abdominal fins. It has keen sense of smell and searches for the female ready to pairing by smell. Having found it, male catches it up and slightly compresses by jaws her back fin, stopping the female and showing to it readiness to copulation. As a rule, deep-water animals differ in small intensity of metabolism processes. For this reason pregnancy at this shark lasts for very long time: about 15 months. Fertility of long-wattled ghost shark is very small: the female gives rise only to two young fishes. But the newborn shark of this species is about 60 cm long at once is able to eat independently and due to the size avoids the fate to be eaten. After birth of posterity the female picks up and eats egg shells. In some days after birth of posterity the female is ready to reproduction again. The young fish reaches length of 1.5 m at the age of 10 – 13 years. In same time it becomes able to breeding. Survival rate at young long-wattled ghost sharks is very high. It partly compensates the low reproduction rate: for all life the female gives birth to no more than two tens of young ones.

Original by Timothy Morris.
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Pristichampsus's avatar
This one is really good :)