Monsters of the Deep

Giant Deep Sea Aristeid Shrimp

When these shrimp reproduce, they produce a ‘monster larva’. These thick-bodied colourful and unusual looking larvae eventually develop into full grown red pigmented deep-sea shrimp.

The larvae are rarely seen and have most often been encountered during studies of gut contents of larger open ocean predators such as tuna and dolphin. The link between the two animals, which until 2012 had been classified as two different species, was only confirmed by comparing DNA sequences of larvae and adult specimens. Prior to this discovery, the question of what the ‘monster larvae’ grow into had been puzzling scientists for nearly 200 years.

These giant shrimp are common in the deep North Atlantic waters, particularly the Porcupine Abyssal Plain. They are scavengers, looking for any food small enough to fit into their mouths, such as marine snow and small invertebrates.

Our specimen was collected in 1998 from the Porcupine Abyssal Plain in the North Atlantic at around 4,830m.

Vampire Squid

The literal translation of the Latin species name is ‘vampire squid from Hell’, a name inspired by its velvety jet-black to pale reddish cloak-like webbing and red eyes.

However, the vampire squid does not really live up to its name since actually feeds on detritus, and does not suck blood! They are neither an octopus nor a squid and actually has its own order, the Vampyromorphida.

Like many deep-sea cephalopods, the vampire squid lacks ink sacs. If disturbed, it will curl its arms up outwards and wrap them around its body, almost turning itself inside-out and, exposing spiny projections called cirri. They also have amazing bioluminescent displays with light organs on the tip of each arm and at the base of each fin. When disturbed, these can glow and pulse and the arms may writhe so that it becomes very difficult to tell one end of the vampire squid from the other. An excellent means to escape predation.

Our two specimens were collected from the tropical eastern Atlantic Ocean at depths between 1,060 and 1,200m, in 1993.

Blobfish

Blobfish are deep-sea fish from the family Psychrolutidae. The name Psychrolutidae comes from the Greek word meaning ‘to have a cold bath.’ This is fitting for the blobfish, because it lives deep in the ocean, where it is certainly cold!

The flesh of the blobfish is primarily a gelatinous mass with a density slightly less than water; this allows the fish to float just above the sea floor without expending much energy to swim. Its relative lack of muscle is not a disadvantage as it generally sits and waits for the prey such as deep-sea crustaceans, to come swimming close enough to eat.

In September 2013, the blobfish Psychrolutes marcidus (McCulloch, 1926) which is found in the deep waters around Australia, (pictured below) was voted the “World’s Ugliest Animal”, based on photographs of decompressed specimens, and was adopted as the mascot of the Ugly Animal Preservation Society. What do you think?

Our specimen is the closely related Psychrolutes macrocephalus (Gilchrist, 1904) collected from depths of 1,600–1,700m in the Arabian Sea, in 2003.

Sloane’s Viperfish

Viperfish are deep sea fish in the genus Chauliodus, and are characterized in having extremely long, needle-like teeth and hinged lower jaws. When the jaw is closed, the teeth fit together to form a ‘cage’ in which prey can be trapped. The teeth are so large that they do not fit inside the mouth and instead pass outside the head, close to the eyes. The jaw can be opened very wide (up to 90°) to catch prey.

This species of Chauliodus lack scales and the pattern of the pigment forms hexagonal areas in which there is a thin deposit of an opalescent substance. The body is covered by a thick transparent coating.

These specimens are from the North Atlantic, although we have no information about the exact location as these were simply labelled as demonstration specimens.

Bonnelli’s Cock-Eyed Squid

Keep one eye out for Bonnelli’s cock-eyed, which clearly have one eye much bigger than the other. Recent research using Remotely Operated Vehicles (ROVs) has shown that in its natural habitat, these animals are almost always observed in an oblique position with the larger eye facing slightly upward and the smaller eye facing slightly downward.

It is thought that the large eye has evolved to break the counter-illumination (a camouflaging technique) of prey items in the water column above the squid, while the small eye is specialized for picking up bioluminescent flashes from predators and prey items in the depths below.

Juveniles do not develop the asymmetric eyes and usually inhabit the upper water column between 100 and 200m, while larger individuals are found between 200 and 800 m with most mature specimens being collected from between 1,000 and 2,200m, where light levels are very low.

Our specimen was collected at depths between 600–1,000m from the Eastern North Atlantic, in an area known as King’s Trough Flank. It was collected in 1984.

Giant Deep-Sea Isopod

Giant isopods are important scavengers in the deep-sea benthic environment. They are mostly carnivorous and feed on carcasses of whales, fish, and squid; they may also prey on slow-moving animals and are known to attack trawl catches.

There are 18 species of giant isopods known to science. These are classified as giants or super-giants. The depth record for any giant isopod is around 2,500m but a few species have been reported from shallower depths.

The specimen we have is a supergiant known as Bathynomus giganteus and comes from the Gulf of Mexico. Giant isopods are not known from the East Atlantic or East Pacific... yet!

These scavengers have been captured, swimming, rolling into balls and hiding in burrows, and are giant relatives of the common garden inhabitants we are all familiar with – the woodlouse!

This specimen is from the Gulf of Mexico collected using an ROV at about 1,000m.

Ghostshark

Like the fire-breathing animal with a goat’s head, a serpent’s tail, and a lion’s body from Greek mythology, deep-sea chimaeras are rather strange. With a tail like a rat, the teeth of a rabbit, true-nostrils like a mammal, and a swimming ability more akin to the flight of a bird, it is clear why these fish are so-named.

Ghostshark is one of the common names for chimaeras, but they aren’t actually sharks at all. Their closest living relatives are sharks, but they branched off from the evolutionary line about 400 million years ago and are among the most primitive fish. Like sharks, the chimaera skeleton is made from cartilage, and they lay eggs in leathery cases and use electroreception to find prey. However, they differ from sharks in having a hidden gills covered by an operculum or gill cover, and non-replaceable rodent-like tooth plates. Chimaeras even have a venomous dorsal spine for protection from predation.

This specimen is from around 1,000m deep in the Rockall Trough, North Atlantic.

Gulper Eel

The gulper eel is renowned for its greatly expanded jaw and large mouth, which is much larger than its body. The jaw is loosely hinged, and can be opened incredibly wide. This large pouch-like extensible lower jaw resembles that of a pelican, hence its scientific name.

The mouth cavity can stretch and expand to a much larger size than is expected for such a small fish and would perhaps be expected to allow this species to capture and swallow large prey items. However, study of the stomach contents or large numbers of specimens have shown that they mostly eat small crustaceans.

Although they have immense jaws, taking up about a quarter of their total length, gulper eels have very tiny teeth and actually quite a small stomach. It is more likely that the expansive mouth functions like a large fishing net. The eel is thought to swim into groups of shrimp or other crustaceans with its mouth wide open, scooping them up and entrapping them before filtering out the excess water and then swallowing the prey.

The gulper eel has been found in temperate and tropical areas of all oceans. In the North Atlantic, it is found at depths from 500 to 3,000m.

This specimen is from the North Atlantic, although we have no information about the exact location as these were simply labelled as demonstration specimens.

Giant Sea Spider

If you are an arachnophobe then the thought of a spider the size of your face is probably a bit creepy. However, the giant sea spider is neither a spider, nor does it bite. So, there is no need to be afraid of this deep-sea monster!

Most sea spiders have eight legs spanning up to 75cm (some have 10 or 12!) but that is where their similarity ends.

Sea spiders don’t have venomous fangs like many of their terrestrial counterparts, they use the a tubular feeding organ on the head called a proboscis to feed on soft-bodied invertebrates, such as jellies and anemones by sucking their contents.

Our specimen was collected at about 3,500m in the Porcupine Seabight in the North Atlantic Ocean in 2001.

Cookie-Cutter Shark

This unusual shark occurs in warm, oceanic waters worldwide, and has been recorded as deep as 3.7km. It normally grows to about 50cm in length, it has a long, cylindrical body with a short, blunt snout.

It is dark brown in colour, with light-emitting photophores along its belly except for a dark “collar” around its throat and gill slits. This dark collar seems to mimic the silhouette of a small fish, while the rest of its body blends into the down-welling light via its ventral photophores.

The name “cookie-cutter shark” refers to its feeding habit of gouging round plugs, as if cut out with a cookie cutter, out of larger animals. Marks made by cookie-cutter sharks have been found on a wide variety of marine mammals and fishes, as well as on submarines and undersea cables.

Our specimen was collected in 1982 during a research cruise to investigate the waters of the Gulf of Guinea, off West Africa. It was taken in a net, at night, fished between 100 and 200m.

Angler Fish

Deep sea angler fish lure prey within reach by dangling their long lures as bait, and some have been known to swallow prey larger than themselves.

In some species, the males are very small in comparison with the females, and live as permanent parasites on their mates. The male attaches himself by biting onto the body of the female. His mouth fuses with her skin and the bloodstreams of the two become connected. The male remains totally dependent on the female for nourishment. This is perhaps because locating each other is so difficult in the darkness.

Angler fish are extremely varied, in both size, habit and morphology – a few can grow to around a metre in length but most are much smaller, less than 20cm long.

We have a number of different species of angler fish which have all been collected in the North Atlantic at depth between 500 and 4,000m.

Dumbo Octopus

These rarely seen octopuses are known as “Dumbo octopuses” because their fins look like the big ears of Disney’s flying elephant Dumbo. They are in the family Opisthoteuthidae, or the umbrella octopuses, which are grouped by the possession of webbing between the arms, forming a characteristic ‘umbrella’ shape.

They have a distinct habit of swimming. They flap their ear-like fins to propel themselves upwards and movement of the arms can be used to help the animal move in any direction.

Dumbo octopuses live on or near the seabed and are most commonly seen resting or crawling on the seabed, although they can also swim. Three species were described using specimens found at the Porcupine Abyssal Plain and from within the Discovery Collections.

This specimen is one of only ten specimens of Grimpoteuthis boylei known to science. It was collected at the Porcupine Abyssal Plain at 4,840m in 1998.

Fangtooth Fish

The most noticeable thing about the fangtooth fish is its mouth full of needle sharp teeth, including its huge front fangs. The fangs on the lower jaw are so large that the fangtooth can’t close its mouth in the normal way. The fangs actually slide into specially formed pockets in the roof of the mouth when the jaw is closed. These pockets extend into sockets on either side of the brain.

Fangtooth fish are voracious predators and are thought to use contact chemoreception to find prey in the deep, dark ocean, relying on luck to bump into something edible. However, there is no need to be afraid of a fangtooth fish since you are never going to bump into one and they are quite small really – never growing more than about 15cm in length.

They are found in temperate and tropical oceans worldwide at depths between 500 to 5,000m. It is naturally well-camouflaged with a dark black/brown colouration and has a distinctive armoured head.

This specimen is from the North East Atlantic, and was collected between 700–800m deep.