Five types of seals spend at least some time in arctic waters: bearded seal, ringed seal, harp seal, hooded seal, and harbor seal. Bearded and ringed seals spend their entire lives in the Arctic. Hooded and Harp seals spend summers in the Arctic, and Harbor seals only occasionally venture north into the Arctic. The bearded seal (Erignathis barbatus) is the largest Arctic seal, and bears the closest similarity to walrus. The ringed seal (Phoc hispida) is the smallest artic seal, and most common. They feed on shrimp, krill, and other small crustaceans. The harp seal (Phoca groenlandica) is a deeper diving seal which feeds on small fish.
Seals (family Phocidae)
The bowhead whale is a baleen whale, feeding on krill and small fish by ingesting large quantities of water and trapping their prey in huge baleen plates in their mouths as the water is expelled. Bowhead whales are quite large, commonly reach 60 feet in length. They have a unique V-shaped spout, which can be seen at a great distance. The Inuit (Eskimos) are allowed by the USA to hunt a limited number of bowhead whales a year. The Inuit traditionally relied upon the spring whale hunt to supply most of their food needs, "Muktuk" or whale-skin is a delicacy, high in Vitamin C, and of great nutritional value in a climate where fruit and vegetables cannot easily be grown.
Bowhead Whale (Baleen mysticetus)
Diatoms, a certain type of algae, are considered the most important primary producers inside the ice with more than 200 species occurring in Arctic sea ice. In addition, flagellates contribute substantially to biodiversity, but their species number is unknown.
There are not many kinds of Arctic fish. Some are found right within and under the ice, and have antifreeze compounds in their blood. Some of the fish are Arctic cod. Fish in the Arctic fill many roles. They eat krill, smaller fish, crustaceans, including bottom-dwelling invertebrates, sometimes salps and jellyfish, and ice algae. What eats fish? Most other Arctic predators, including squid, other fish, polar bears, seals, and whales—and as larvae, they are eaten by jellyfish, ctenophores, large crustaceans, other fish, and most things larger than they are.
The mighty polar bear is the undisputed king of Arctic predators. Weighing up to 1500 pounds, the polar bear is perfectly adapted to a life on the pack ice. Its white coat aids in both camouflage and heat retention. Polar bears primarily feed on ringed seals, but when seal meat is scarce they survive on fish, seabirds, and scraps. In summer, polar bears will eat berries and vegetation much like their cousin the grizzly. The world population of polar bears has recently been healthy, estimated at 25,000 in 1991, with about 15,000 living in the Canadian Arctic.
Sea Stars & Sea Urchins
Sea urchins along with sea stars, brittle stars, sea cucumbers and feather stars belong to the phylum of Echinoderms, a name that refers to their spiny skin. All have in common the pentamerous (five)-radial symmetry of their bodies as well as the presence of calcareous parts in their body. Starfish (more correctly known as sea stars as they are only very distantly related to fish), are marine invertebrates belonging to the phylum Echinodermata, class Asteroidea.
Detritus, including older ice algae, dead organisms, and fecal pellets, falls to the seafloor, and is eaten by bottom-living urchins, sea stars, and mussels. Together with plankton, detritus is an important constituent of seston (materials in suspension), and may also accumulate at the base of a water column. Much detritus is used as a source of nutrition for animals. In water-based ecosystems, most detritus is suspended in water, and gradually settles.
If "plankton" are the drifters, then “zooplankton” are the animals that drift in the water. They range from nearly-microscopic to centimeters or even meters long. The most common zooplankton in all the oceans are called copepods—little shrimp-like animals that can be nearly microscopic to almost a centimeter long. Most copepods eat small particles, which can by phytoplankton, small zooplankton, or bits of dead material called detritus. Some copepods are predators, mostly on other copepods. They can detect the vibration of swimming prey or the prey's chemical scent, and track them down for lunch. Like other junior members of the food chains, copepods get eatern by bigger animals.
Jellyfish live in all oceans, from the surface to very deep water where there is no light. They have simple umbrella-shaped bodies that are soft and jelly-like, or gelatinous, without much internal structure. Most are at least partly transparent. All jellyfish are predators: they have tentacles that carry stinging cells that they use to catch and eat smaller ocean animals, including copepods, krill, and larval fish. Many jellyfish species that live in deep water in warmer parts of the ocean live close to the surface in polar regions where the water is very cold all year.
Phytoplankton are often referred to as the "plants" of the ocean. They obtain energy and produce organic matter through photosynthesis, and so they live in the surface layers of the ocean. Some common groups of phytoplankton are diatoms, coccolithophorids and dinoflagellates. They, together with the ice algae, form the base of the food chain for the Arctic ecosystem, and are eaten by copepods.
Walrus (Odobenus rosmarus)
Walruses are divided into two subspecies- Atlantic and Pacific. Pacific walruses are much larger, weighing up to 1.3 tons compared to the .75 tons of the Atlantic variety. They live in shallow, icy seas, using the floes for mating and birthing. Walruses are bottom feeders, using their whiskers to find clams and other bivalves in shallow waters. Both males and females grows tusks from their upper jaws. Walruses are extremely social, hauling out on the ice in large herds, and walrus mothers are extremely protective of their young.