Seafriends - Chimaerids, elephant fish and ghost sharks
Chimaerids (ghost sharks and elephant fish) are related to sharks and rays, but they have a skin covering their gills, with a single opening instead of gill slits. Their skins are smooth and their dorsal fins are preceded by a single large spine.

In Greek mythology, a Chimera is a fire-breathing female monster with a lion's head, a goat's body and a serpent's tail. (Gk khimaira= female goat)

Chimaerids are closely related to sharks, having a similar cartilaginous skeleton but lacking the flattened body form of skates and rays. Representatives of this order are found in all the oceans of the world, but they are generally restricted to cool temperate regions in waters between 200 and 1200m depth. They can be distinguished from sharks by  their gill slits being covered with a skin (operculum), leaving a single opening on each side. Chimaerids also have smooth skins without the dermal denticles of sharks. They also have a single spine in front of their first dorsal fins, which can be laid flat as in bony fishes. Their heads are grooved with lateral lines and their upper jaws are fully fused to their heads, unlike in sharks where the upper jaw is only loosely attached to the skull. Their teeth are modified to form flattened crushing plates with sharp cutting margins; two pair in the upper jaw, and a single pair in the lower jaw.
Male chimaerids have the normal claspers or intromittent sexual organs that are present in the sharks and rays alongside their pelvic fins, but they also have a second pair of flat, retractable claspers in front of the pelvic fins. These are usually armed with hooks and are probably used only to grip the female during mating. There is also a club-like frontal clasper on top of the head. All chimaerids are oviparous, laying large eggs in a horny case which is deposited on the bottom. Like most sharks and rays, development is slow and the young do not hatch until six months to a year after the eggs are laid.
Cimaerids live mainly on soft muddy bottoms on the deeper parts of the continental shelf or on the continental slope. They feed mainly on shellfish and bottom-living invertebrates, as well as a few small fish.

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Callorhinchidae: elephant fishes
Callorhinchus milii: elephant fish

Four closely related species are now recognised, requiring further revision of this class.
Hardnosed fishes: (L: callosus= hardened skin; Gk: rhinos=nose; milii=?)
Maori: reperepe

Elephant fishes are found in the Antarctic Basin and the South Pacific. The New Zealand species grows to 120 cm long, and is common along the east coast of the South Island, where it comes in-shore for breeding. Its curious trunk-like proboscis is used for locating shellfish.

Fishing: The elephant fish is exploited commercially, particularly off the Canterbury coast. They are also occasionally netted off the North Island, south of East Cape and south of Kaipara on the west coast. Outside the breeding season, elephantfish live on the boundary of the continental shelf in waters up to 200m deep. The fish are caught commercially during their inshore migration, either in trawls or in setnets, and the total annual landings are about 1000 tonnes. The firm white fillets are of good edible quality, resembling that of hapuku (groper, sea bass), but requiring prior soaking in fresh water to eliminate a slight ammonia taste. The flesh is either used locally in the fish and chips trade or is exported to Australia.

Elephant fish and egg capsuleDescription: A silvery coloured fish with brown markings, half a metre to over one metre long. On its snout it has a fleshy skin flap, which it uses for finding its food in the muddy bottoms of deep water. Its two dorsal fins are high and triangular, and the upper lobe of its tail is shark-like, with a lower lobe immediately preceded by a pointed anal fin, appearing to be part of the tail. Immediately before its first dorsal fin it has a large spine, which is thought to be poisonous.

Fins/size/weight: size 0.5 to 1.2m.

egg capsule of elephant fishLife history: Adults migrate inshore during spring to shallow spawning grounds in water less than 40m deep. An important spawning ground of this fish is found off Canterbury, near Sumner Beach. On the sandy or muddy bottom the females lay large eggs contained in a yellow-brown horny capsule measuring about 25x10 cm, and which look like pieces of seaweed. In the centre of the egg case is a cavity in which the embryo develops. From one end of this cavity a passage, closed by a special valve, leads to the exterior, and it is through this passage that the young fish in due course, escapes. The young hatch 6-8 months later (April), and as with most sharks, are slow in growing, taking about 5 years to reach maturity. Large numbers of the discarded egg cases are frequently washed ashore on Sumner Beach.



Chimaeridae: ghost sharks
Several species of ghost shark are found in the deep water around New Zealand. Two of these are shown here. The giant ghost shark (Chimaera phantasma) is rarely seen, is much larger than the other two and the males have distinctive three-lobed claspers.

Hydrolagus novaezelaniae: dark ghost shark
(Gk hydros=water ; lagus= ?) Maori: repe hikuroa

Dark ghost sharkThe dark ghost shark is a relative of the elephant fish but lacks its trunk-like snout. It has a long, tapering tail. It is also smaller, averaging 50-60cm. This dark, mottled fish, occurs over the outer continental shelf in 350-1000m deep water, where it is caught in trawl nets.
This fish has a conical snout and an elongate, tapering body. On its back it has a triangular first dorsal fin (and spine) and a long, low second dorsal fin. The dark ghost shark is dark grey above with a mottled pattern of distinct silver-white markings, and pale silver-grey underneath. The mouth is small, and located well back and beneath the snout.

Pale ghost sharkHydrolagus sp: pale ghost shark
The pale ghost shark is found in deeper water than the dark ghost shark, and it is also larger, averaging 60-70cm. Its snout is more rounded than that of the dark ghost shark, and its colour is paler. Its skin is pale brown above, with a few distinct darker bands, and it is white below. Pale ghost sharks occur further south than the dark ghost sharks, being common on the Campbell Plateau and on the Snares Shelf south of Stewart Island.

Rhinochimaeridae: long-nosed chimaeras
Long-nosed chimaeras are rare, deepwater fishes of temperate and tropical seas, living to depths of 2000m. They are larger than the other chimaeras. Their snouts are elongated into cylindrical or flattened points, and they have long tails.

Hariotta raleighana: long-nosed chimaera

(hariotta=?; raleighana= named after Raleigh)

Long-nosed chimaeraIncluding its long, tapering snout and fins, this species is usually between 1 and 1.5m long. Its body is more elongate than the other chimaerids. Its snout is hard and resilient, and rich in sensory organs, being used to dig in soft  muddy bottoms in search of shellfish and crustaceans that make up the bulk of its diet. Its skin is orange-brown in colour, paler beneath, and it has some irregular darker markings. It is commonly found in waters between 350 and 700m depth.

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