Longnose Catshark

• Maximum length58.4 cm (23 in)
• WeightNot recorded; well under 1 kg
• LifespanNot measured
• Depth rangeAbout 180–1,888 m (590–6,200 ft)
• DietDeep-sea squid, crustaceans, small bony fish
• IUCN statusLeast Concern (assessed 2024)

How to recognise a longnose catshark

A longnose catshark on a sorting table looks less like a shark than like something moulded from wet clay. The body is soft and flabby, the skin loose, and the whole animal is a uniform blackish brown, darkest on the belly, with thin pale margins picked out along the edges of the fins. That combination of soft dark body and pale fin edging is the signature of the genus Apristurus, the deepwater catsharks, and it is shared by dozens of species worldwide.

The snout gives this one its name. It is long, flattened from above and bluntly rounded at the tip, taking up a large part of the head, with narrow nostrils on its underside. The eyes are small horizontal slits with a green reflective shine, set high on the head, and behind and below them the mouth opens as a wide arch reaching back past the eye. The teeth are tiny, each with a slender central cusp and a pair of small cusplets, arranged in many rows: a grid for holding soft prey, not for cutting.

Fin placement is the third check. The two dorsal fins are of similar size, the first starting behind the pelvic fins rather than over them, and the anal fin is long and low, about twice as long as it is high, running back to a small notch just before the tail. The tail itself is long, narrow and almost horizontal, with no lower lobe worth the name. Pectoral and pelvic fins are broad and rounded.

How big does a longnose catshark get?

The largest longnose catshark on record measured 58.4 cm (23 in) in total length. Females examined in collections top out lower, at about 52 cm, and a typical adult of either sex is somewhere between 48 and 55 cm, which is to say the length of a forearm.

Hatchling size has never been described for this species. Apristurus eggs are laid in flat, horny cases a few centimetres long, and where hatchlings of related deepwater catsharks have been measured they emerge at roughly 8 to 12 cm; an honest answer for A. kampae is that nobody has caught one small enough to say. Sizes at maturity are equally unmeasured, which is common for a genus represented in museums by a few dozen specimens.

Weight has not been published either, and an estimate would be misleading: deepwater catsharks have poorly calcified skeletons, watery muscle and a large oily liver, so they weigh far less than their length suggests. A 58 cm longnose catshark is a light, floppy animal that fits in two hands. Against the 1.8 m diver on the size bar below it barely registers, which is a fair picture of the genus as a whole.

Where longnose catsharks live

The species belongs to the eastern North Pacific and, so far as confirmed records go, to nothing else. It has been taken along the continental slope off central and southern California, south along the outer coast of Baja California, and inside the Gulf of California in Mexico, which is where the type specimens came from. That places it roughly between 38°N and 23°N. A report from near the Galápagos Islands has never been confirmed and may refer to another member of the genus.

Vertically the range is enormous. Specimens have come from about 180 m down to 1,888 m, which spans the upper slope, the oxygen minimum zone of the eastern Pacific and the true deep sea below it. Most catches are from the middle of that band, several hundred metres down, on soft muddy bottoms where the slope falls away.

Everything about the habitat is constant and hostile to an air-breathing observer. There is no daylight below about 1,000 m and effectively none where this shark is common; the water is 4 to 8 °C, the pressure at 1,500 m is about 150 atmospheres, and food arrives mostly as material sinking from far above. Our page on where sharks live sets the deep slope against the shallow habitats most people picture.

What longnose catsharks eat

The few stomachs that have been examined held deep-sea cephalopods, crustaceans such as shrimps and mysids, and small bony fish. That is the standard diet of a mid-slope Apristurus, and it fits the anatomy exactly: a wide mouth that can be thrown open quickly, hundreds of tiny multi-cusped teeth that grip soft bodies, and a flabby build that suits slow searching rather than pursuit.

Finding food in permanent darkness is the real problem, and the longnose catshark solves it with the long snout rather than with the eyes. The underside of that snout is studded with the pores of the ampullae of Lorenzini, which detect the weak electrical fields of living muscle, so sweeping a broad flat snout across the sediment works like a metal detector passed over sand. The lateral line adds the movement of anything that stirs, and a keen sense of smell narrows the approach to carrion.

Scavenging almost certainly matters more than hunting. Deep-slope catsharks are regularly filmed by baited cameras arriving at fish carcasses within an hour, and a shark that spends most of its energy simply staying in place cannot afford to chase. The most likely picture is an animal cruising a few centimetres above the mud, eating whatever small live prey it startles and whatever dead material it finds first.

Behaviour, and what the old accounts get wrong

Copies of the original page claim that longnose catsharks hunt nocturnally and rest in groups by day. There is no basis for it. At the depths where this species is common no daylight reaches the bottom, so there is no day and no night to organise a routine around, and no one has ever observed a group of them doing anything. It is worth saying plainly, because invented behaviour is the commonest fault in deep-sea shark writing.

What can be said rests on the body itself. The species is negatively buoyant only slightly, thanks to a large liver filled with low-density oil, so it can hover above the sediment with very little effort, which is the only affordable way to live where food is scarce. Muscle is watery and pale, built for slow continuous cruising rather than bursts. The skin is soft and the denticles fine, reducing weight further.

Breathing is passive. Unlike fast oceanic sharks, which must swim to force water over the gills, a bottom-living catshark pumps water through its mouth and spiracles while lying still, which is what lets it wait on the mud for hours; our page on how sharks breathe explains the two systems. Beyond that, honest answers are short: no one knows whether the species migrates, whether it defends space, or how long an individual stays in one patch of slope.

Reproduction and lifespan

The longnose catshark is oviparous. Females lay their eggs in pairs, one released from each of the two oviducts at a time, each sealed inside a tough amber-coloured horny case with tendrils at the corners that catch on the bottom or on whatever structure is available. The embryo inside lives entirely on its yolk and gets nothing further from the mother; among the reproductive strategies set out on our page on how sharks reproduce, this is the simplest and the oldest.

In cold deep water that is also the slowest. Egg cases of deep-sea catsharks can take many months to hatch, far longer than the six to ten months typical of shallow species, because development tracks temperature and the bottom here sits near 5 °C. Where the eggs are deposited, how many a female lays in a season and what the hatchlings look like are all unrecorded for A. kampae.

Lifespan is equally blank. No vertebral ageing study has been done on the species, and deepwater catshark vertebrae are so weakly calcified that growth bands are difficult to read even when someone tries. Small catsharks from shallower water generally live ten to twenty-five years, and cold, slow-growing deep-sea relatives can be expected to live longer still, but that is a general expectation and not a measurement; our guide to how long sharks live explains why these figures are so hard to pin down.

Is the longnose catshark dangerous?

No, and the reasons are absolute rather than statistical. The species lives between roughly 180 and 1,888 m, and recreational scuba diving stops at about 40 m. It reaches 58 cm, and its teeth are a couple of millimetres long, built to grip a shrimp. The SharkSider database holds no incident attributed to it, and there is no mechanism by which one could ever occur.

The only people who see the animal are crews on deep-water trawlers and the researchers who sort their catch, and even for them the risk is limited to a scrape from the sandpaper skin. The species sits with the other deep-sea catsharks and dogfishes on our list of the least dangerous sharks, and anyone wanting to know which species actually matter off the Californian coast should read the state page rather than this one.

The SharkSider database has no incident attributed to this species. The database draws on the International Shark Attack File, the Global Shark Attack File and verified local reports, and is updated weekly.

Conservation status

The IUCN Red List assessed the longnose catshark as Least Concern in 2024. That is a change worth noting, because older summaries, including the previous version of this page, still call it Data Deficient, a classification it carried while too little was known to judge. The reassessment rests on depth: the great majority of the species' vertical range lies below the depths that trawlers and trap fisheries work off California and Baja California, so most of the population is effectively out of reach.

Where fisheries and sharks do overlap, on the upper slope, the species turns up as bycatch in bottom trawls and in traps set for sablefish. It has no commercial value; animals brought up from several hundred metres rarely survive the pressure change, so discarding them is not a solution either. Numbers taken are small, and no directed fishery has ever existed for it.

The realistic long-term concerns are the ones affecting the whole eastern Pacific slope: the expansion of the oxygen minimum zone as the ocean warms, which squeezes the depths available to slope animals, and the prospect of deep-sea mining and deeper trawling pushing human activity into water that has so far been left alone. None of this is unique to one catshark, and the wider pattern is set out on our page on why sharks are endangered.

Relatives and look-alikes

The genus Apristurus contains around forty described species and is notoriously difficult; several are separated only by snout proportions, the position of the dorsal fins and the shape of the dermal denticles under a microscope. In the same ocean the nearest relative is the Panama ghost catshark of the eastern tropical Pacific, and the white ghost catshark and longfin catshark fill equivalent roles in the north-eastern Atlantic.

The species most often confused with it off California is not an Apristurus at all. The brown catshark shares the slope, the depth band and the plain dark colour, but it is smaller, warmer brown and has a much shorter snout. The filetail catshark, common in the same trawls, is identified instantly by the row of enlarged denticles along the upper edge of its tail. Shallower again, the swell shark of Californian kelp beds is boldly blotched and inflates itself with water when threatened, and no one who has seen the two would mix them up.

• Panama Ghost Catsharkspecies profile
• White Ghost Catsharkspecies profile
• Longfin Catsharkspecies profile
• Brown Catsharkspecies profile
• Filetail Catsharkspecies profile
• Swell Sharkspecies profile

Written and reviewed by

SharkSider Editorial Team

A small team focused on researching sharks and making marine biology easy to understand. Every page is reviewed against current species records and the SharkSider attack database, and updated when new incidents or research appear.

Published October 26, 2022 · Last updated September 22, 2026 · No incident attributed to this species in the SharkSider attack database, which is updated weekly.