(DRAFT) - Taxonomy
Species whale, beluga
Species Id M120107
Date 26 AUG 96
TAXONOMY
NAME - whale, beluga
OTHER COMMON NAMES - beluga whale, belukha and white whale
ELEMENT CODE -
CATEGORY - Marine Mammals
PHYLUM AND SUBPHYLUM - Vertebrata,
CLASS AND SUBCLASS - Mammalia,
ORDER AND SUBORDER - Cetacea, Odontoceti
FAMILY AND SUBFAMILY - Monodontidae,
GENUS AND SUBGENUS - Delphinapterus,
SPECIES AND SSP - leucas,
SCIENTIFIC NAME - Delphinapterus leucas
AUTHORITY - Linnaeus
TAXONOMY REFERENCES - 125, 166 and 178
COMMENTS ON TAXONOMY -
The species is sometimes called "belukha" to differentiate it from the
beluga sturgeon (the fish from which caviar is obtained) *166*. It is also
sometimes called the white whale *125*.
Taxonomy - 1 (DRAFT) - Status
Species whale, beluga
Species Id M120107
Date 26 AUG 96
STATUS
Coded Status
Marine Mammal
See Comments
REFERENCES FOR STATUS - 166 and 125
COMMENTS ON STATUS -
Belugas have been hunted for centuries by native whalers for food, oil, and
"porpoise leather". They are still being hunted in limited numbers in the
Soviet Union, and by the Eskimo (Inuit) natives of Arctic Canada. Due to
the high level of mercury in belugas, they are no longer considered edible,
and hunting belugas for food has been banned. Some belugas have been
captured for display by oceanariums. The current population is estimated to
be 62,000-86,000 *166*.
The average annual kill in Alaska and western Canada waters is about 570
(365 in Alaska and 205 in Canada). These estimates are from harvest figures
and struck-and-lost estimates. Because data are so meager and information
on the survival rate of unretrieved whales is almost completely lacking,
estimates of the total annual kill are very imprecise *125*.
Status - 1 (DRAFT) - Distribution
Species whale, beluga
Species Id M120107
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine OW0 V 1
Estuarine AB. H 6
Estuarine AB. V 6
Riverine UB. H 6
Marine OW0 V 1
Estuarine AB. H 6
Estuarine AB. V 6
Riverine UB. H 6
Marine OW0 V 1
Marine, intertidal BB. V 1
REFERENCES FOR NWI - 125
Habitat Associations - 1 (DRAFT) - Food Habits
Species whale, beluga
Species Id M120107
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 166 and 125
LIFESTAGE FOOD FOOD PART
General Squid, Octopus See Comments
General Perciformes See Comments
General Clupeiformes See Comments
General Salmoniformes See Comments
General Lampridiformes See Comments
General Osteichthyes See Comments
General Pleuronectiformes See Comments
General Gadiformes See Comments
General Beryciformes See Comments
General Crustaceans See Comments
General Molluscs See Comments
General Bivalve Molluscs See Comments
Juvenile Crustaceans See Comments
Juvenile Gadiformes See Comments
Juvenile Salmoniformes See Comments
Juvenile Perciformes See Comments
Important Salmoniformes See Comments
Important Crustaceans See Comments
Important Clupeiformes See Comments
Important Gadiformes See Comments
REFERENCES FOR IMPORTANT FOOD - 125
REFERENCES FOR ADULT FOOD - 125
REFERENCES FOR JUVENILE FOOD - 125
COMMENTS ON FOOD -
More than 100 kinds of organisms have been identified in the diet of
belugas. General prey in stomachs collected along the northwest coast of
Alaska include benthic invertebrates, squid, octopus, semidemersal fish
(Arctic cod, saffron cod, herring, whitefish, smelt, char), and demersal
fish (sculpins, suckers, eelpout). Salmon, eulachon, saffron cod, tomcod,
herring, and smelt have been identified as prey items for belugas summering
south of Bering Strait. Food items are swallowed whole.
Octopus may be a significant spring food. Shrimp are also eaten. Of fish
species consumed in spring, Arctic cod is taken in greatest numbers. Even
though cod is the most commonly consumed fish, the whales feed more
extensively in spring on invertebrates.
Fish are the dominant food item in coastal areas of Alaska in summer. In
general, belugas seem to feed on whatever fish species are most abundant and
easy to catch. Thus, they prey on herring, rainbow smelt, capelin, salmon,
char, eulachon, whitefish, saffron cod, and Arctic cod as these become
seasonally abundant. Sculpin, flounder, sole, blenny, burbot, lamprey,
Food Habits - 1 (DRAFT) - Food Habits
Species whale, beluga
Species Id M120107
Date 26 AUG 96
shrimp, mussels, octopus, and squid also contribute to the summer diet. In
the northern Bering and southern Chukchi seas saffron cod is the most
commonly consumed species.
Differential feeding occurs by age and sex class. In the western Bering Sea
in summer, yearlings take primarily cranonid shrimp and navaga cod; 2-, 3-,
and 4-year-olds take primarily navaga cod and chum salmon; and older
animals take primarily chum salmon. Other authors have noted that young
animals take small prey. Yearlings supplement a diet of milk with capelin,
sand lance, shrimp, and small bottom-dwelling crustaceans.
Although younger and older whales of both sexes prey on the same species,
older belugas eat significantly larger saffron cod than do young whales, and
males eat significantly more sculpin (larger fish than saffron cod) than do
females. In another study, adult males fed primarily on large fish, and
females preferred food items such as sand lance, octopus, and nereid worms
*125*.
COMMENTS ON ADULT FOOD -
Although younger and older whales prey on the same species, older belugas
eat significantly larger saffron cod than do young whales *125*.
COMMENTS ON JUVENILE FOOD -
In the western Bering Sea in summer, yearlings take primarily crangonid
shrimp and navaga cod; 2-, 3-, and 4-year-olds take primarily navaga cod
and chum salmon; and older animals take primarily chum salmon. Other
authors have also noted that young animals take small prey. Yearlings
supplement a diet of milk with capelin, sand lance, shrimp, and small
bottom-dwelling crustaceans *125*.
Food Habits - 2 (DRAFT) - Environment Associations
Species whale, beluga
Species Id M120107
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Water Temperature: Below 15 degrees C
J Water Temperature: Specified in Comments
G
G Water Depth Preference: Specified in Comments
G Aquatic Habitat Zonation: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 125
REFERENCES FOR LIMITING ENVIRONMENTAL ASSOC_ - 125
REFERENCES FOR FEEDING ADULT ENVIRONMENTAL ASSOC_ - 125
REFERENCES FOR RESTING ADULT ENVIRONMENTAL ASSOC_ - 125
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 125
REFERENCES FOR RESTING JUVENILE ENVIRONMENTAL ASSOC_ - 125
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
TEMPERATURE: Beluga whale distribution is generally limited to water
temperatures below 15 deg C.
ICE: In winter most belugas inhabit ice-permeated offshore waters. They
must have access to air and therefore inhabit areas where geographic,
oceanographic, or meteorologic factors cause ice motion and the formation
of openings. Ice coverage affects seasonal distribution.
DEPTH: During open-water months, nearly all major concentrations of
belugas occur in shallow bays or in estuaries of large rivers north of 40
deg N.
SALINITY: Soviet scientists have noted that belugas are most abundant in
coastal shallows in years with heavy continental runoff. This association
of beluga abundance with freshwater runoff is likely related to fish
abundance *125*.
COMMENTS ON RESTING ADULT ENVIRONMENTAL ASSOC_ -
TEMPERATURE: Beluga distribution is generally limited to water
temperatures below 15 deg C. However, all ages and both sexes inhabit warm
estuarine waters during summer.
ICE: In winter most belugas inhabit ice-permeated offshore waters.
Complete ice coverage excludes use by belugas, while partial coverage
Environment Associations - 1 (DRAFT) - Environment Associations
Species whale, beluga
Species Id M120107
Date 26 AUG 96
encourages use. Ice coverage affects seasonal distribution.
DEPTH: During open-water months, nearly all major concentrations of
belugas inhabit shallow bays or estuaries of large rivers north of 40 deg
N.
SALINITY: Soviet scientists have noted that belugas are most abundant in
coastal shallows in years with heavy continental runoff. This association
of beluga abundance with freshwater runoff is likely related to fish
abundance *125*.
COMMENTS ON FEEDING ADULT ENVIRONTAL ASSOC_ -
ICE: Prey and ice distribution often act together to influence beluga
distribution. Movement of prey into coastal areas is synchronized with ice
departure in spring, and association of prey with the ice edge during other
seasons attracts belugas. In most coastal areas south of Bering Strait,
the arrival of belugas coincides with the breakup and movement of ice
offshore and the arrival of large runs of fish.
DEPTH: Belugas seem to be more successful in obtaining prey in the rivers
where prey are concentrated than in the bays where prey are more dispersed.
Belugas in Bristol Bay feed at the mouth of the Snake River, where salmon
runs are smaller than in other rivers in Bristol Bay. However, the mouth
of the Snake River is shallower, and hence may concentrate the prey.
TEMPERATURE: There is evidence that concentrations of belugas in
warm-water estuaries in Kotzebue Sound, Kasegaluk Lagoon, areas north of
Bering Strait, and eastern Canada are more closely associated with
temperature than prey abundance.
SALINITY: Association on beluga abundance with freshwater runoff is likely
related to fish abundance *125*.
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
TEMPERATURE: Researchers have assumed that most calving takes place in
coastal estuary areas. However, some calving, at least, takes place in
colder offshore areas *125*.
COMMENTS ON RESTING JUVENILE ENVIRONMENTAL ASSOC_ -
TEMPERATURE: Noenates have thinner blubber and a higher surface-to-volume
ratio than other age classes; warmer waters may favor their survival and
growth *125*.
Environment Associations - 2 (DRAFT) - Life History
Species whale, beluga
Species Id M120107
Date 26 AUG 96
LIFE HISTORY
PHYSICAL DESCRIPTION: The beluga's body is thick, muscular, and tapered at
both ends, with a small head and narrow caudal peduncle (tail stock). Its
head is rounded with a short beak and a prominent, protruding forehead
called the "melon." The neck of the beluga is narrower than the necks of
other whales, and it also differs from most whales--whose neck vertebrae are
fused--in that its 7 neck vertebrae are free, which allows it to nod and
turn its head.
Adult belugas are almost completely white. Calves are gray to pinkish
brown. At 2 years of age they become a dark gray; at 3-4 years they turn a
lighter gray, and at full maturity they become white, though they retain
some dark color on the edge of the flippers and flukes.
Because it has no dorsal fin, the beluga can swim freely under floating ice.
instead of a fin it has a narrow ridge which runs down the rear half of its
back. the ridge is sometimes notched and may be a dark color. The flippers
are short, broad, and may be curled up at the tip in adults. The fluke is
broad, deeply notched in the center, and ornately curved.
Adult males measure 5 meters (14-16 ft), with a maximum length of 5.3 m (20
ft), and weigh about 3,300 lbs. Adult females measure 3.9-4.2 m (13-14 ft),
with a maximum length of 5.2 m (17 ft), and weigh about 3,000 lbs *166*.
REPRODUCTION: Calving areas: Calving generally occurs throughout the
beluga's circumpolar distribution between March and September, with a peak
in June and July. In northwest Alaska the first post-parturient female was
taken on 29 April and the last full-term fetus was recovered on 18 July.
Calving peaks from mid-June to late July. Influx of animals to nearshore
areas in mid-June could bias samples so that the peak in calving occurs
earlier than it seems.
Calving occurs in all coastal Alaska waters where belugas aggregate in
summer. Neonates and afterbirths are reported from Bristol Bay, Norton
Sound, Kotzebue Sound, Kasebaluk Lagoon and adjacent marine waters, and the
eastern Beaufort Sea. Calving areas in Cook Inlet are not known. Calves
were noted in Cook Inlet in mid-July but not in June, and it was
hypothesized that calving begins between mid-June and mid-July, perhaps at
the large river estuaries in the upper inlet.
Researchers have assumed that most calving takes place in coastal estuary
areas. However, some calving, at least, takes place in colder offshore
waters. Calving sometimes occurs prior to or during the spring migration.
Neonate calves are seen in the spring leads during April, May, and sometimes
in March, and harvests in the leads along the northwest Alaska coast include
female belugas in late pregnancy or recently in post-parturient. Here
parturition must occur in very cold water.
The average increase in standard length during the first year of life was
46.3 cm in a sample of 6 neonates and 4 1-year-olds from the northwest
coast. Data are inadequate to show the increase in length during the first
few months of life.
The proportion of calves in various aggregations of belugas has been
determined from aerial surveys and photogrammetry. Such methods may be
reasonably accurate during June and July when neonates are small, but are
much less accurate by late August when some calves are as long as yearlings.
Sex ratio: Although size differences between male and female adult belugas
are significant, other outward sexual dimorphisms do not commonly
Life History - 1 (DRAFT) - Life History
Species whale, beluga
Species Id M120107
Date 26 AUG 96
distinguish males and females in the wild. Consequently, sex ratios are
determined from specimens. From 533 carcasses a sex ratio of 1:1 was
reported. There were, however, large deviations from unity in subsamples.
Subsamples throughout the beluga's range show large differences in sex
ratio, age composition, and reproductive status. Some sex and age
segregation is apparent. Large deviations in pod composition pose problems
in obtaining unbiased samples; sex ratios in harvest samples are also
biased by hunter selectivity. Sex ratios of 1:1 have also been reported for
other populations.
Age at sexual maturity: The mean age at sexual maturity is slightly younger
for females than for males. (Calculations of age are based on the
assumption of two growth layers per year in teeth. Age at sexual maturity
in females here means the age of initiation of first pregnancy.) The age of
sexual maturity for females is 4-7 years, with first births at 5-8 years of
age. Of 22 primiparous females from the Alaska coast, 54% conceived at age
4, 41% at age 5, and 5% at age 6. In a sample of 52 females, all animals up
to age 4 were sexually immature (N=28); 33% of the 5-year-olds (N=9) and
94% of the 6-year-olds (N=16) were sexually mature. However, most of the
samples were obtained at the approximate season of their birth dates; thus,
4-year-old females were not pregnant when taken during June, though some
would have become so prior to their fifth birthday.
Increases in testis volume and spermatogenic activity indicate sexual
maturity in males. Males reach sexual maturity at 7-9 years.
Pregnancy rates: A 3-year reproductive cycle is most typical in belugas.
Of sexually mature females sampled from harvests along the northwest coast
of Alaska, 35% were not pregnant, 35% were newly pregnant, and 30% carried
full-term fetuses or had given birth. However, high pregnancy rates in 6-
to 22-year-old females suggest that some conceive more frequently than once
in 3 years. It's been estimated that in eastern Canada 25% of mature
females have a reproductive cycle of 2 years and 75% have a cycle of 3
years.
Life span and reproductive life: Belugas may live more than 30 years.
Because older animals lose tooth dentine layers, maximum longevity is
unknown. However, minimum ages of the oldest animals in one sample are two
males 38+ years and a female 35+ years. Lifespans of 25 and 30 years have
been estimated. The lifespan of males has been estimated at 40 years and
lifespan of females at 32 years.
Reproductive rate: The reproductive rate is the fraction of calves produced
annually in the total population, without correction for mortality.
Estimates are calculated from the percentage of calves seen during surveys
and also from the crude birth rate and the proportion of mature females in
the population. The crude birth rate is the average annual rate at which a
mature female will produce a calf.
Estimates of reproductive rate from calf counts range from 0.06 to 0.14 and
estimates from the annual rate of calf production range from 0.09 to 0.13.
Estimates of the reproductive rate derived from carcasses use the equation
r=bp, where r is the reproductive rate, b crude birth rate, and p is the
proportion of mature females in the population. There are no valid
estimates of net reproductive rates in beluga whale populations because
current data do not provide a basis for estimating natural mortality.
From a sample of 265 females, crude birth rate was estimated at 0.33
Life History - 2 (DRAFT) - Life History
Species whale, beluga
Species Id M120107
Date 26 AUG 96
(range=0.31-0.35) and the reproductive rate at about 0.11. This matches the
reproductive rate estimate of 0.10-0.12 adopted by the International Whaling
Commission Subcommittee on Small Cetaceans.
Possible sources of error in determining reproductive rates from calf counts
include difficulty in seeing smaller, darker-colored calves; difficulty in
distinguishing calves from yearlings; and possible segregation of population
components. Sources of error in calculating reproductive rates extrapolated
from the proportion of females in the population and reproductive rates of
adult females include biases in the sex and age composition of the sample
collected, and the difficulty of assessing the reproductive status of adult
females.
Lactation: The duration of dependent nursing may be considerably shorter
than the total nursing period. The duration of dependent nursing has been
reported to be 12-18 months. From observations of larger calved attending
lactating females, it was concluded that lactation ends when the calf is
between 1 and 2 years old. Other researchers estimated that lactation lasts
about 23 months and ranges from 18 to 32 months. Weaning occurs well after
the first solid food is taken.
Lactation does not always inhibit ovulation and pregnancy. Milk has been
found in several pregnant females. About 25% of sexually mature females
become pregnant during lactation, presumably 10 months after having given
birth.
Gestation: Gestation is estimated to last 14-15 months. This estimate is
from measurements of fetuses and neonates from Cumberland Sound and Hudson
Bay. Assuming a 14.5 month gestation, and knowing that the peak of births
is from mid-June to mid-July, mating should peak in April. However,
specimen analyses and observations of behavior during spring suggest that
most mating takes place before April.
Of 13 newly pregnant females collected from late April and early May
harvests, 9 had fully developed corpora lutea, 2 showed signs of recent or
imminent ovulation, and 2 had embryos. No females obtained in June or July
showed signs of recent ovulation. Of the 34 sexually mature males, only 2
(both taken in mid-June) were in breeding condition. the other 32 males
(including 14 obtained in April and May) were in early to mid-spermatogenic
retrogression. Thus, although a small proportion of belugas may be in
breeding conditon in and after late April, the majority appear to breed
earlier.
The peak mating time may be between late February and early April. If so,
either peak calving occurs prior to mid-June, or the gestation period is
longer than supposed, or belugas have delayed implantation. The possibility
of delayed implantation cannot be ruled out.
Outside Alaska, the breeding period has been estimated from data on peak
calving dates and gestation period. Peak mating is estimated to occur in
Cumberland Sound in mid-May, in Hudson Bay between mid-April and mid-May,
and in the St. Lawrence River estuary from April to June. Along the Siberia
coast conception occurs in early May. These dates parallel mating dates
which would be estimated from calving and gestation information from Alaska,
and are derived in a similar manner, but they do not closely correspond with
peak mating periods determined from analysis of beluga reproductive status.
NATURAL MORTALITY: Data on natural mortality rates of belugas are extremely
Life History - 3 (DRAFT) - Life History
Species whale, beluga
Species Id M120107
Date 26 AUG 96
limited. From comparison with mortality data for the pilot whale
(Globicephala melaena), a natural annual mortality rate of 0.045 was
suggested for belugas. The validity of this comparison, however, is
questioned by the Intermational Whaling Commission Subcommittee on Small
Cetaceans. Relationships between mortality, maximum length, and lifespan
for various species of cetaceans were calculated. Generally, there is a
high correlation among these factors in cetaceans. On the basis of body
length and lifespan the natural annual mortality rate for belugas should be
slightly in excess of 0.10. However, this seems too high, given that (1)
recruitment appears to be in the range of 0.09 to 0.12; (2) these animals
have been harvested for food for centuries, in some areas without notable
declines; and (3) there are substantial losses due to ice entrapment which,
although it is a cause of natural mortality, bears no likely relationship to
body length and lifespan ratios. It seems unlikely that populations could
have sustained harvesting and ice-entrapment with such a narrow margin of
gain between natural mortality and recruitment rates.
Causes of natural mortality among beluga populations include entrapment in
ice and predation by killer whales (Orcinus orca) and polar bears (Ursus
maritimus). Entrapment in ice has been attributed primarily to failure of
belugas to migrate to open water prior to freezup in autumn, and to deep
penetration of whales into pack ice during the spring migration. Recent
evidence from the Soviet coast suggests that mortality due to entrapment
could, at times, significantly affect the population size. However,
entrapment does not always result in mortality.
Predation by humans and polar bears is frequently associated with ice
entrapment and is often the immediate cause of death. In some cases the
entrapped whales might have otherwise survived; in others they might not
have. In recent years trapped whales used by hunters have been included in
catch statistics and thus death statistics from harvests and entrapment are
not separable. In fact, Native settlements may have developed in areas
close to locations of frequent ice entrapment. From the few sightings of
entrapment in areas far from human settlements, despite increased
observation oppotunities in recent years, it was concluded that the
proportion of entrapped whales that die undetected is small.
Polar bears occasionally prey on belugas, commonly in ice traps. Although
belugas are vulnerable to polar bear predation during certain periods, even
when in shallow estuaries, they are not a primary food of polar bears.
Killer whales also prey on belugas. Beluga whale range in the north may
have evolved partly to avoid killer whale predation. Although killer whales
occur in areas inhabited by belugas, they probably cannot give birth because
of the cold water, or enter heavy ice because their dorsal fin renders them
poorly adapted for breaking through ice.
Although parasites and their associated lesions have been described, their
role in beluga mortality is not known. Of 9 belugas collected from the
Churchhill area of Hudson Bay, Canada, 8 were heavily infested with Pharusus
pallasii, a parasite of the hearing organs. The presence of P. pallasii in
the cerebrospinal fluid suggested that infestation could produce erratic
behavior, due to changes in spinal fluid pressure. These data are only
preliminary, and no similar studies have been done in Alaska. Parasites are
not known to cause death.
EFFECTS OF HUMAN ACTIVITIES: Harvests and incidental catches have the most
clear and direct effects on beluga whales. Threats posed by development and
Life History - 4 (DRAFT) - Life History
Species whale, beluga
Species Id M120107
Date 26 AUG 96
other human activities are more difficult to evaluate, yet these activities
are expanding rapidly and have the potential of significantly affecting
belugas. Residents of some coastal areas assert that changes in beluga
distribution in the past decades are due to habitat alteration from human
activity.
In particular, continued oil and gas development, development of mines and
hydroelectric plants, increased commercial fishing, and changes in hunting
and recreational activities will likely degrade water quality, reduce prey,
and increase noise pollution. Information on the sensitivity of beluga
whales to these factors is limited. Because they form dense aggregations,
their population as a whole can be significantly affected by local
degradation of the environment. The effects of habitat changes on belugas
could take various forms, including direct mortality, displacement,
increased stress or illness, changes in reproductive success, changes in fat
reserves or energy expenditures, and changes in the ability to communicate,
navigate, or locate prey.
Marine mammals may abandon areas as their habitat deterioates, or they may
exhibit high site tenacity. Belugas return to estuaries in northern Quebec
every year despite severe overhunting that has reduced population levels.
Although belugas in Kotzbue Sound are intensely hunted, and in the Mackenzie
Delta are hunted and exposed to dramatic increases in vessel traffic and
industrial noise, they return each year. In other areas where vessel
traffic has increased, belugas have disappeared. Thus, tenacity may better
reflect the critical value of the habitat than the level of human-imposed
stress *125*.
LIFE HISTORY CODES -
Foraging Sites: Standing water - Limnetic zone
Foraging Sites: Standing water: Profundal zone
Breeding/Spawning Season: March
Breeding Spawning Season: April
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Breeding/Spawning Season: July
Breeding/Spawning Season: August
Breeding/Spawning Season: September
Display Site: Water
Spawning Site: Standing Water
Gestation/Incubation Period: Greater than 8 months
Average Number of Offspring/Reproductive Effort: 1
Parental Care of Young: Female
Dispersion: Clumped
REFERENCES FOR LIFE HISTORY- 125
Life History - 5 (DRAFT) - Management Practices
Species whale, beluga
Species Id M120107
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Other management practices [specified in comments]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 125
COMMENTS ON MANAGEMENT PRACTICES -
EFFECTS OF HUMAN ACTIVITIES: Harvests and incidental catches have the most
clear and direct effects on beluga whales. Threats posed by development and
other human activities are more difficult to evaluate, yet these activities
are expanding rapidly and have the potential of significantly affecting
belugas. Residents of some coastal areas assert that changes in beluga
distribution in the past decades are due to habitat alteration from human
activity.
In particular, continued oil and gas development, development of mines and
hydroelectric plants, increased commercial fishing, and changes in hunting
and recreational activities will likely degrade water quality, reduce prey,
and increase noise pollution. Information on the sensitivity of beluga
whales to these factors is limited. Because they form dense aggregations,
their population as a whole can be significantly affected by local
degradation of the environment. The effects of habitat changes on belugas
could take various forms, including direct mortality, displacement,
increased stress or illness, changes in reproductive success, changes in fat
reserves or energy expenditures, and changes in the ability to communicate,
navigate, or locate prey.*125*
Primary beluga management concerns are maintenance of populations within the
optimum sustainable range, protection of habitat, and prevention of
interference with subsistence activities through diversion of belugas away
from traditional hunting areas. Possible adverse human impacts include
harvesting, noise pollution, contamination of habitat, net entanglement, and
competition for-or depletion of-prey species as a result of commercial
fishing.
The most important management issue is to identify and protect critical
habitat. It is also important to identify management units (stocks),
determine abundance and productivity (sustainable yield) of each, and
determine the number of animals being taken from each stock and whether
there are any problems with current harvest levels. In many cases, basic
information about distribution and abundance is needed before the more
complex questions of causal relationships between human activities and
belugas can be answered.
Current subsistence harvests in Alaska and western Canada are below historic
levels. In the absence of information on natural mortality, population
levels, and trends, it is not possible to accurately quantify whether
current harvest levels are sustainable. However, with the possible
exception of the Yukon Delta, Norton Sound, and Cook Inlet (about which data
are too poor to allow a reasonable appraisal), there is no indication that
current harvest levels cannot be sustained.
Management Practices - 1 (DRAFT) - Management Practices
Species whale, beluga
Species Id M120107
Date 26 AUG 96
Several habitats may have already been partially abandoned by belugas.
Disturbance from human activity, primarily vessel traffic and hunting,
appear to be the major reasons. This is of much concern to Kotzebue Sound
residents and has been mentioned as a problem along much of the northern and
western Alaska coasts. It is likely that noise pollution will continue to
increase, and may become an important subject for study in protecting
habitat.
In one instance, overfishing of prey species by humans may have caused a
temporary distributional change. This does not currently appear to be a
major area of concern; however, so little is known about winter feeding
that assessing impacts of foreign-fleet harvests on availability of prey is
difficult.
Net entanglement does not appear to be a problem anywhere. Entanglement
could cause mortality in Cook Inlet or Bristol Bay in the future; however,
little is known about the ability of belugas to avoid gear. Entanglement in
Cook Inlet should receive special attention because the beluga population
there is small and isolated.
The effects of contaminants on belugas can probably be best studied in the
St. Lawrence Estuary where waters are more polluted, and studies are already
underway. No baseline data are available on contaminant concentrations in
belugas off Alaska *125*.
Management Practices - 2 (DRAFT) - References
Species whale, beluga
Species Id M120107
Date 26 AUG 96
References
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.
166* American Cetacean Society. 1988. ACS Whale Fact Pack. American
Cetacean Society San Pedro, CA.
178 * U.S. Department of Commerce. 1988. Marine Mammal
Protection Act of 1972 Annual Report. National Oceanic and
Atmospheric Administration (ed.):38.
(Note Ref. 178 [or 179] is Ref. 195 in Marine References.)
References - 1