With their backward-turned rear flippers and blubbery bodies, Arctic pinnipeds like the bearded, ringed and spotted seals can look clumsy — though charming — as they wriggle across the ice.
But in the ocean, where they spend much of their time, they're as graceful and athletic as can be. Still, no seal can always be in the water; Arctic seals need the ice's solid surface to carry out basic survival activities, from resting to molting to raising young.
So as sea ice dwindles due to global warming, so does the hope for these seals' long-term survival. The last administration failed to protect many species on the brink of extinction. Help save them now. Climate change is scary news for seals in many more ways than one. Besides degrading and eliminating necessary sea-ice habitat, warming depletes their prey, makes them more vulnerable to predators and disease, and leads to increased shipping activity which brings with it even more dangers.
Add to all this the ever-increasing threats of oil and gas development, hunting, pollution and commercial fishery bycatch, and the implications are overwhelming. The spotted seal is closely related to and shares some habitat with the harbour seal Phoca vitulina.
Although the biology and habits of these two species differ, there is some evidence of inter-breeding. The diet of the spotted seal varies geographically, seasonally and by age, but it is known to include crustaceans, cephalopods and fishes such as herring, capelin, pollock, eelpout, sand lance and cod. Known predators are sharks, killer whales, walruses, Steller sea lions, polar bears, brown bears, wolves, foxes and some large birds. Statistics There is some variation in spotted seal size between different populations.
Adult males measure 1. Pups are born measuring cm in length and weighing kg. Adult spotted seals can dive to depths of over m. Females reach sexual maturity at years of age, males at years. Spotted seals can live to at least 35 years of age. Please Donate! Click here to donate. Distribution and Numbers Also known as the Larga seal, the spotted seal inhabits the ice and waters of the north Pacific Ocean and adjacent seas, being found along the continental shelf of the Beaufort, Chukchi, Bering and Okhotsk Seas and south to the northern Huanghai Sea and western Sea of Japan.
Status The lack of accurate population data means that the effects of natural events and human-caused activities on the species are difficult to determine. There is no longer a Japanese commercial spotted seal hunt but some seals are still hunted on an ad-hoc basis when ice conditions allow.
Gestation lasts 7 to 9 months, but a delay in implantation of the blastocyst after breeding can extend the length of the entire pregnancy to almost a year. Pups are weaned after 2 to 4 weeks, when their lanugo is shed and they can leave the ice to begin learning to forage for themselves in the water. Pups nurse for 2 to 4 weeks after birth.
Both the mother and her current mate remain with the pup during this time. Once the pup has been weaned at about a month old , it is abandoned by the mother and left to fend for itself.
Female spotted seals have been observed adopting strange pups if they are separated from their own. If they survive to adulthood, they can live to a maximum of 30 to 35 years of age. They quickly take to the water when they sense a possible threat. Spotted seals are solitary during parts of the year and gregarious at other times of year. They are often seen at haul-outs, which are sites on the shore or on ice where anywhere from a few individuals to large groups leave the water and gather.
These sites are usually located near abundant food sources. There are four types of OAs seen throughout the year, divided up by the point in the life cycle at which they occur: preliminary, reproductive, molting, and recovery a rehabilitative phase after the energy-intensive reproduction and molting phases.
OAs can differ in the sex and age of participating individuals over the course of the year as the type of OA changes. Bradford and Weller, ; Nesterenko and Katin, Home range sizes for spotted seals are not reported in the literature.
Olfaction is believed to be extremely important in maintaining relationships between individuals, especially between mates and between mothers and their offspring.
One of the most important reasons for the gathering of many spotted seals at haul-out sites is so this olfactory as well as tactile contact can occur between individuals. If a mother and offspring are separated, they will call to each other and touch noses once reunited.
Calling and nosing have also been observed between mating pairs. When navigating under ice, spotted seals rely mostly on vision, then on auditory and tactile cues. Beier and Wartzok, ; Burns, et al. Fish are the primary component of the spotted seal's diet, most commonly herring Clupea pallasii , pollock Theragra chalcogramma , cod Gadus macrocephalus , and capelin Mallotus villosus.
They also feed on mollusks and crustaceans. The pelagic zone of the ocean is where they spend most of their foraging time. The spotted seal's seasonal movements between sea ice and shore is believed to be partially driven by migration of these prey species. Dehn, et al. Predators known to occasionally prey on spotted seals include sharks, killer whales, walruses, sea lions, polar bears, brown bears, wolves, several species of birds, and, of course, humans.
Spotted seals, however, do not constitute a significant portion of any of these predator's diets. They avoid predation by gathering at haul-out areas, being cryptically colored, and being agile in the water. Spotted seals mainly feed in the pelagic zone of the ocean, where their primary prey is schooling fish. Depredation by seals has been shown to have an effect on populations of fish, but there has been no study done that definitively shows the role spotted seals play in the population changes of their prey species.
Spotted seals are not thought to be important prey for any other species besides some humans that hunt them for subsistence. Alaska Natives and some Russian hunters rely on spotted seals as part of their subsistence lifestyle. In addition to using them as food, skins are used for clothing. Seal oil has gained some popularity as a health supplement for lowering blood pressure.
Meyer, et al. Spotted seals sometimes take fish from nets. Northridge, With climate change resulting in a reduction in the area of sea ice, there is concern for populations of spotted seals as well as other polar marine species as they face possible changes in habitat and prey distribution. Spotted seals are also victims of fishing bycatch and poaching. At this time the species is considered to be data deficient by the IUCN.
This was due to reports of decreasing populations on Asian coasts. Spotted seals were once considered a subspecies of harbor seal Phoca vitulina largha. However, Shaughnessy and Fay in recognized spotted seals as a distinct species. Spotted seals and harbor seals are sympatric in some areas, and are believed to be sister groups within seals.
Spotted seals are known by many different names to Alaskan Natives: qasigiaq Inupiaq , gazigyaq St. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico. In otherwords, Europe and Asia and northern Africa.
Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria. More specifically refers to a group of organisms in which members act as specialized subunits a continuous, modular society - as in clonal organisms.
Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a now extinct synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds. Iteroparous animals must, by definition, survive over multiple seasons or periodic condition changes. An aquatic biome consisting of the open ocean, far from land, does not include sea bottom benthic zone.
National Oceanic and Atmospheric Administration. Status Review of the Spotted Seal Phoca largha. Springfield, VA: Department of Commerce.
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