(DRAFT) - Taxonomy
Species seal, bearded
Species Id M120103
Date 26 AUG 96
TAXONOMY
NAME - seal, bearded
OTHER COMMON NAMES - bearded seal (English), square flipper (Norwegian sealers), morski zaits (Western Russian term meaning sea hare), laktak (Eastern Russian term), mukluk (Siberian Upik Eskimo) and oogruk (Inupiat Eskimo term)
ELEMENT CODE -
CATEGORY - Marine Mammals
PHYLUM AND SUBPHYLUM - Chordata,
CLASS AND SUBCLASS - Mammalia,
ORDER AND SUBORDER - ,
FAMILY AND SUBFAMILY - ,
GENUS AND SUBGENUS - Erignathus,
SPECIES AND SSP - barbatus,
SCIENTIFIC NAME - Erignathus barbatus
AUTHORITY - Erxleben
TAXONOMY REFERENCES - 170
COMMENTS ON TAXONOMY -
The scientific name, Erignathus barbatus, is descriptive of two very
characteristic features of the bearded sea. The generic name Erignathus is
Greek and refers to the deep jaw. The specific name, barbatus, is of Latin
origin and refers to the relatively long and numerous moustachial
vibrissae.*170*
Two subspecies have been described: E. b. barbatus from the Laptev Sea,
Barents Sea and North Atlantic Ocean into Hudson Bay; and E. b. nauticus
from the remaining portions of the Arctic Ocean and the Bering and Okhotsk
seas. The validity of the division into subspecies has been questioned,
however.*125*
Taxonomy - 1 (DRAFT) - Status
Species seal, bearded
Species Id M120103
Date 26 AUG 96
STATUS
Coded Status
Other, no FMP or PMP exists
See Comments
REFERENCES FOR STATUS - 125
COMMENTS ON STATUS -
Currently, there are no research or management programs for bearded seals in
the United States. Basic harvest monitoring is needed as well as research
addressing the ecological interactions of bearded seals with competing and
prey species. At a minimum, harvest monitoring should include records of
the numbers taken by susistence users and Soviet sealing ships. The age and
sex composition of the takes also should be recorded and analyzed for
indications of temporal changes in the population structure. The age and
sex biases of harvests in different regions and seasons will have to be
investigated.*125*
Status - 1 (DRAFT) - Distribution
Species seal, bearded
Species Id M120103
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine OW0
REFERENCES FOR NWI - 125
COMMENTS ON HABITAT ASSOCIATIONS -
The range of bearded seals broadly overlaps that of other ice-inhabiting
pinniped, partly due to an ability to make and maintain breathing holes,
and to their less discriminating selection of ice type. The proportion of
bearded seals wintering in the shorefast ice in unknown but probably small.
Ice is important to bearded seals as a substrate for resting, whelping,
and molting. Bearded seals whelp over a wider area and longer time span
than do ther phocids in the Bering Sea, possibly because bearded seals are
able to use less predictable ice.*125*
Habitat Associations - 1 (DRAFT) - Food Habits
Species seal, bearded
Species Id M120103
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 125
LIFESTAGE FOOD FOOD PART
General Crustaceans Not Specified
General Molluscs Not Specified
General Fish Not Specified
General Bivalve Molluscs Not Specified
Important Crustaceans Not Specified
Important Molluscs Not Specified
REFERENCES FOR GENERAL FOOD - 125
REFERENCES FOR IMPORTANT FOOD - 125
COMMENTS ON FOOD -
Bearded sea;s are primarily benthic feeders, showing variations in diet with
age, location, season, and perhaps with long-term changes in the composition
of benthic communities. A wide variety of invertebrate and fish prey has
been reported, but decapod crustaceans and molluscs make up most of the diet
throughout the bearded seal's range. Major prey in the Bering, Chukchi, and
Beaufort seas include crabs, clams, shrimps, and Arctic cod. No significant
differences have been observed in the feeding habits of male and female
bearded seals, but age-related changes have been observed. Shrimp are a
larger component of the diet of first and second-year seals than of older
seals, who eat more clams.*125*
COMMENTS ON ADULT FOOD -
Bearded seals are primarily benthic feeders utilizing mostly epibenthos
(organisms occurring on, rather than in, the bottom), although organisms of
the infauna and some demersal fishes are also consumed. Although the total
array of food items consumed by bearded seals is large, relatively few types
of organisms comprise the bulk of their diet. These include brachyuran
crabs, shrimp, clams, sculpins, and sometimes arctic or saffron cod.
Geographical variation in diet is largely a reflection of local faunal
differences. Major prey types remain the same among areas, however, the
species eatern may change.*170*
COMMENTS ON JUVENILE FOOD -
The nursing period in bearded seals is comparatively hsort, lasting 12-18
days. During this time the weight of the pup increases approximately 150%,
mostly in the form of an accumulated blubber layer. Weaning occurs when the
female abruptly deserts the pup. Some independent feeding occurs during the
latter part of the nursing period; newly weaned pups are active feeders.
The apparently eat more isopods, hippolytid shrimps and saffron cod than
adults do, and fewer brachyuran crabs, pandalid and crangonid shrimps,
sculpins, and flatfishes.*170*
In the Bering Sea, hippolytid shrimp are eaten more frequently by pups,
Food Habits - 1 (DRAFT) - Food Habits
Species seal, bearded
Species Id M120103
Date 26 AUG 96
while pandalid shrimp are more common in stomachs of older seals. Isopods
and saffron cod are more important to younger seal; brachyuran crabs,
sculpins, and flatfishes are more important to older seals.*125*
Food Habits - 2 (DRAFT) - Environment Associations
Species seal, bearded
Species Id M120103
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
Environment Associations - 1 (DRAFT) - Life History
Species seal, bearded
Species Id M120103
Date 26 AUG 96
LIFE HISTORY
Morphology:
Bearded seals are covered with relatively short, straight hair. They have
none of the distinct and diagnostic color patterns such as spots, rings or
bands found on other species of seals. Most adults are basically light to
dark gray, being slightly darker down the middle of the back. Coloration is
sometimes tawny-brown to dark brown. Term fetuses and newborn pups have
dark (usually brown), dense, slightly wavy hair with light coloration on the
facial region and one to four broad, transverse light bands on the crown and
back. At weaning, the pelage resembles that of older seals.*170*
Maximum life expectancy of bearded seals is about 30 years. The oldest
animal recorded from the Bering and Chukchi seas was 26 years of age. Based
on data obtained from animals killed by coastal Eskimo hunters, about 75% of
the population was ten years of age or younger, and over 95% was 20 years or
younger. At some locations, samples appeared to be significantly biased
toward younger aged seals, lending credence to the hypothesis that younger
animals occur in larger numbers close to shore.
Most male bearded seals become sexually mature, as indicated by testes and
baculum size and by the onset of spermatogenic activity, at ages six to
seven. Some females first ovulate at the age of three years but most do not
become pregnant until the age of six years. Observed ovulation rates are:
17% at age four; 50% at age five; 80% at age six; and 100% at age eight.
Life expectancy:
The sex ratio of bearded seals appears to change with age. Studies
conducted within the Bering-Chukchi area indicate that at birth males
predominate, although the ratio is very close to one-to-one. In collections
of animals older than pups, females composed 53-55%. This suggests a higher
mortality rate in males although other factors such as sex-related
differences in behavior, distribution, or sinking rate may influence the sex
ratio of harvested animals. Maximum life expectancy of bearded seals is
about 30 years. The oldest animal recorded from the Bering and Chukchi seas
was 26 years of age. Based on data obtained from animals killed by coastal
Eskimo hunters, about 75% of the population was ten years of age. Based on
data obtained from animals killed by coastal Eskimo hunters, about 75% of
the population was ten years of age or younger. At some locations, samples
appeared to be significantly biased toward younger aged seals, lending
credence to the hypothesis that younger animals occur in larger numbers
close to shore.
Predators:
The major predators of bearded seals in the Bering-Chukchi region are polar
bears and humans. The magnitude of polar bear predation is unknown;
however, in one study undertaken in Alaskan waters, five of 71 pinnipeds
(7%) killed by bears were bearded seals.*170*
REFERENCES FOR LIFE HISTORY- 170
Life History - 1 (DRAFT) - Management Practices
Species seal, bearded
Species Id M120103
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Existing Other management practices [specified in comments]
REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 170
COMMENTS ON MANAGEMENT PRACTICES -
Bearded seals may be competing increasingly with walruses for clams and with
commercial fisheries for crabs. At the same time they may be subjected to
increasing rates of harvest. Currently, however, there are no research or
management programs for bearded seals in the United States. Basic harvest
monitoring is needed as well as research addressing the ecological
interactions of bearded seals with competing and prey species.
Currently, there are no research or management programs for bearded seals in
the United States. Basic harvest monitoring is needed as well as research
addressing the ecological interactions of bearded seals with competing and
prey species. At a minimum, harvest monitoring should include records of
the numbers taken by susistence users and Soviet sealing ships. The age and
sex composition of the takes also should be recorded and analyzed for
indications of temporal changes in the population structure. The age and
sex biases of harvests in different regions and seasons will have to be
investigated.*125*
The efficacy of strip transect surveys for censusing bearded seals needs to
be tested in surveys stratified primarily for bearded seal habitat. Survey
methods more suitable to the low densitieds of bearded seals should be
sought. Behavioral data are needed to develop correction factors for aerial
surveys. The diurnal haulout cycle of bearded seals during the spring
survey period should be investigated using radiotelemetry. Seasonal changes
in haulout timing by different age and sex classes should be determined.
Data on haulout rhythms should be used to correct for the proportion of
seals submerged and uncounted during surveys. The ratios of seals on the
ice to seals in the water at peak haulout hours and other times should be
determined and applied as corrections to surveys flown over the course of
several hours. The variance in the proportion of seals on the ice at
different times of day should also be determined by a study of haulout
behavior. It may be that the best time of the day to survey will be when
the varience is lowest, whether or not that corresponds with the time of
peak haulout.*125*
Management Practices - 1 (DRAFT) - References
Species seal, bearded
Species Id M120103
Date 26 AUG 96
References
170 * J. Burns, K. Frost and L. Lowry (eds.)1985. (7). Alaska
Department of Fish and Game: 96.
125* Lentfer, J.W. (ed.). 1988. Selected Marine Mammals of Alaska,
Species Accounts with Research and Management Recommendations.
Marine Mammal Commission Washington, D.C pp 275.
References - 1