#783: Urchin

The Urchins are around 950 species of marine echinoderms. He is characterised by his symmetry and spines, which protect him from predation. They are dioecious, with individuals being either male or female. Males tend to live in more elevated and exposed positions, whereas females favour low-lying locations. Urchins feed on algae, which is consumed through an orifice in his lower half - this acts as both mouth and anus. It is studded with calcium carbonate "jaws" and features a fleshy tongue-like structure. Whilst Urchins have no apparent eyes, his entire body is a sensory organ and sensitive to touch, light and chemicals. Locomotion is slow, but achieved by adhesive tube feet.

#781: Umbrella-mouth Gulper

The Umbrella-mouth Gulper is a deep sea fish, named for his enormous jaws. These are used to consume crustaceans and it is thought that he swims along, mouth agape, collecting everything in his path. Squids and smaller invertebrates also are collected, as well as gret mouthfuls of water. These are flushed out through his gills. As he matures, his jaws and teeth atrophy, to be replaced by enlarged olfactory organs. These may help him locate a mate in his almost lightless habitat. It is suspected that he will die soon after spawning. Very little else is known about this bizarre predator, as it lives at such extreme depths that it is generally only seen when inadverently captured in a fishing net.

#690: Sea Squirt

Sea Squirts are sedentary Tunicates, firmly fixed to rock, coral or some other substrate. They are named for their tunic-like rigid covering, which is composed of living tissue. The upper surface contains two siphons, which violently expels water when the animal is removed from its environment, hence the common name of "squirt". The upper, larger, siphon contains cillia, which suck in the water, removing the nutrients and expelling the rest out of the lower siphon. Sea Squirts are hermaphrodites, and fertilisation is external. Juvenile larvae are free-swimming, but within 36 hours will have settled into a sessile lifestyle.

#689: Sea Snake

The Sea Snakes are a subfamily of venomous snakes adapted almost entirely to a marine existence. Many species are laterally flattened, and all have a paddle-like tail. Only one Genus, the Laticauda (which includes this Banded Sea Krait), is capable of moving on land. The other species have greatly reduced scales, rendering them helpless outside the aquatic environment. Sea Snakes feed on fish and small cephalopods. Although most species are considered fairly mild-natured, they are amongst the most venomous of all snakes. These bites are generally quite painless, with no swelling of the wound, but the symptoms include headache and general muscular pain, followed by partial paralysis and the possibility of renal failure or cardiac arrest.

#684: Scorpionfish

 

The Scorpionfish are a Family of predominantly-marine fish, which contain some of the most venomous fishes in the world. There are hundreds of species, spread across the tropic and temperate seas. They are characterised by their spines, which adorn their body and appendages, and which contain venom glands. Most are ambush predators, relying on camouflage to hide them from their prey and using suction to, literally, inhale it. This fellow is a Spinycheeked Scorpionfish, found around the Florida coast.

Other species I have drawn:
Lionfish

And similar but not closely related (same Order, NOT same Family):
Stonefish (to come)
Demonstinger

Creature Feature #234: Fin Whale

The Fin Whale is one of the longest animals in the world, measuring up to 27m. She is sleek and slender, capable of speeds greater than that of an ocean liner - about 37 km/hr. She mates in low-latitude seas during winter, giving birth to her calf some 11 months later. Newborns are about 6m long and will remain with the mother for 6-7 months, accompanying her to the summer feeding grounds. She can live up to 140 years. Fin whales are occasionally predated by orca, but their main threat comes from humans, both through whaling and collisions with boats.

Creature Feature #227: Fanworm

Fanworms are an Order of annelid worm, characterised by their fan-like appearance. Their first two body segments are fused, with feathery tendrils that allow them to filter feed. To protect their lower end, they construct a parchment-like tube from debris around them, such as sand and shell fragments, cementing them together with mucus. This they retreat into when not feeding. There are numerous species, with some - like this Mediterranean Fanworm - having only one fan, whereas other species have multiple or spiral fans. The Mediterranean Fanworm is found in shallow estuaries, living at depths of up to 30 m and growing up to 40 cm tall.

Creature Feature #225: Fangtooth

Although the pelagic Fangtooth may look a most fearsome foe, he grows no more than 18cm in length. He lurks in the deep, dark recesses of the ocean, as far as 5,000 m deep. Unlike most deep sea denizens, he does not use light to locate prey, relying on touch chemoreception and sheer chance. His disproportionately large mouth and teeth assist in the consumption of any prey he might find. His lower fangs are so long that they do not neatly fit into his jaw, and it is difficult, if not impossible, for him to close his mouth. Juvenile fish are planktonic and live near the surface, descending to the depths when they attain their adult form.

Creature Feature #212: Emperor Shrimp

Emperor Shrimp are a tiny - less than 2cm long - crustacean widely distributed across the Indo-Pacific. He forms a commensal relationship with a host, such as a nudibranch or sea cucumber. Scurrying along this larger creature, he feeds on its waste products whilst also keeping it clean of parasites. He is an omnivore and a detrivore. If danger threatens, he will scurry beneath his larger host, or bury himself in the substrate. Emperor Shrimps have found their way into marine aquariums, but very little seems to be known about them and they are very reliant on the presence of a potential host species.

Creature Feature #206: Elysia

Elysia are a Genus of sea slugs that graze on algae. Some species hijack the chloroplast from the plant matter, using it to coat the inside of their digestive tract and allowing them to survive on photosynthesis. This chlorophyll affects their colour, making them the vibrant green. Elysia are hermaphrodites, and are able to self-fertilise, but do so very rarely, preferring to mate with another individual. Eggs are laid in a long string, and these hatch into a shelled larva.

Creature Feature #186: Eagle Ray

The Eagle Ray are a group of cartilaginous fishes comprised of a number of species spread across seven Genera. Their horizontally flattened body, with their wing-like fins, is idea for swooping and soaring through the water, and they are even capable of breaching the water and soaring above for several metres before diving back in again. To hide from predators,  he comes to rest on the ocean floor, creating a shallow scrape in the sand and his cryptic, spotted colouration provides camouflage. Eagle Rays are ovoviviparous, with the female retaining the eggs until they hatch and then giving birth to up to four pups at a time.

Creature Feature #180: Dumbo Octopus

The Dumbo Octopus earns her name from her two ear-like fins, which reminded her discoveries of Disney's flying elephant, Dumbo. She is a deep-sea dweller, living at depths of over 3,000 metres and is thus the deepest diving of any octopus species. She hovers above the ocean floor, searching for invertebrates to scoop up with her barb-covered arms and swallow whole. To move she uses a combination of her fins, her limbs and also by shooting water through her siphon: a funnel that she can use to hold water within her mantle, and then expel it at high speed, thus propelling herself forward.

Creature Feature #179: Dugong

The Dugong is a gentle ocean dweller, quite closer related to the elephant. It is thought that she inspired early tales of  mermaids, for her tendency to stand upright in the water. She is often referred to as the Sea Cow, named for her tendency to graze on sea grasses. Her hind limbs have been modified into a divided tail fluke, like that of a dolphin, and which she uses to manouvere herself languidly through the water. She had been greatly exploited in the past, hunted significantly throughout her range and now suffers under the fishing industry. She is long-lived - can live for over 70 years - and a slow breeder, and like too many animals, is suffering from population decline.

Creature Feature #175: Dragonfish

What a horrifying creature of the deep! What a nightmare it must be to meet one of these whilst exploringthe ocean!

Well, unless you are a tiny fish, you have nothing to fear - for this deep sea denizen measures a mere 15 centimetres in length. Found at depths of 1,500 meters, her entire life is spent in near-permanent darkness and thus - like many of her ray-finned compatriots - she has developed some rather creative ways in which to capture her prey (although given her size, she's got many larger fish to fear). These take the form of bioluminescence - both in her barbel and along her length, as well as a patch beneath her eye. She uses her barbel as a lure, flashing it and waving it to tempt smaller fish into reach of her gaping mouth and fierce teeth. As a lot of her prey is also bioluminscent, her stomach is black-lined, so that the light cannot leak out and alert potential predators to her presence as she digests her meal.

Creature Feature #174: Dragonet

Dragonets are small Perciform fish, displaying an array of cryptic colours. You may think that there is nothing cryptic about this fellow - the Mandarin Dragonet - but in his coral reef home, his psychedelic blend of colours make him extremely difficult to pinpoint as he creeps across the ocean bed,  gobbling up small crustaceans and other invertebrates. Fiercely territorial, he will live happily with a female but will quickly see off any potential rivals. He is a popular addition to saltwater aquariums, but his feeding requirements are very specific and some will no adapt to captivity and die of starvation.

Creature Feature #168: Dorado

The Dorado, or Dolphinfish, is a surface-dwelling rayfinned fish also known as mahi-mahi. He is short-lived, with most living no more than 4-5 years, but grows very fast and matures at around 4-5 months of age, and can breed year round with females producing between 80,000 and 1,000,000 eggs each spawning event. Of these massive numbers, only a small proportion will survive, but it is enough to keep the population stable. His Spanish name - Dorado - translates as "golden", and when out of the water his scales do change colour, eventually fading to a muted yellow-grey upon death. A popular recreational fish, the Dorado is considered of "least concern" and appears on many menus.

Creature Feature #165: Dolphin

The Dolphin is a fully aquatic mammal, noted for her intelligence and playful behaviour. There are almost forty species of dolphin, with the most widely recognised being the Bottlenose Dolphin - named for the shape of her snout. Despite being reliant on the water for survival, the Dolphin still needs to breath air through a single blowhole on the top of her head. Her body is streamlined and sleek with fore limbs modified into powerful flippers and her spine tapering into a propelling tail. Her hearing and eyesight are sharp, with her hearing being linked to her lower jaw. She emits high-pitched sound, sonar, to navigate underwater via echolocation.

Creature Feature #164: Dogfish

Dogfish are a Family of cartilaginous fish and are, essentially, small sharks. This Spiny Dogfish was once the most abundant fish in the world, but thanks to over-fishing he is now vulnerable to extinction in many parts of the world, populations around Europe having decreased by 95%. Male fish sport a pair of pelvic fins, known as "claspers" which he uses to grasp the female when mating. Fertilisation is internal, and the eggs are retained within the female until they hatch. This process is known as "ovoviviparity".

Creature Feature #157: Demonstinger

It is hard to believe that something this beautiful can be venomous.

The Demonstinger belongs to the same Family as the Stonefish - something you really do not wish to step on. He does not have scales, instead his skin is covered in a knobby array of wartlike glands and spines which help to camouflage him against the oceanfloor. An ambush predator, he uses his ray fins to "walk" along the sea bed, partially burrowing himself into the substrate to await his unsuspecting prey. If disturbed, he fans out his fins as a warning. If that fails, his venom is a powerful combination of neurotoxin, hemotoxin, and cardiotoxin, resulting in severe pain, shock paralysis, tissue necrosis, and even death.

Perhaps not suprisingly, he has no natural predators.

Creature Feature #131: Cowfish

The Cowfish is a species of Boxfish, named for her two long "horns", found in both genders. She can grow up to 50cm and makes her home in coral reefs of the Indo-Pacific region. A solitary bottom-feeder, she blows jets of water into the sandy floor to expose invertebrates and other tasty treats. She is a slow swimmer, and easily caught by hand wherein she emits a grunting noise. If she becomes threatened or extremely stressed, she can exude a deadly toxin - ostracitoxin - which is fatal to other Boxfish. Despite these traits and her territorial nature, she is finding popularity amongst the tropical fish trade.