EEBTEST 2 REVIEW.doc

34 views10 pages
13 Apr 2012
School
Course
Professor

For unlimited access to Study Guides, a Grade+ subscription is required.

TEST 2:
BIODIVERSITY: the variability among living organisms from all sources including among others, terrestrial, marine and other
aquatic ecosystems and the ecological complexes of which they are part.
Conservation of any species is highly complicated and includes factors such as its ABUNDANCE, RATE OF REPRODUC-
TION, EXTINCTION RATE, NATURAL DISASTERS, MANKIND’S INFLUENCE, etc.
ex. global warming -> melting arctic ice recedes away from land -> polar bears swim further to hunt -> unable to
properly feed cubs. ---- estimated that polar bears will become extinct within next 100 years or sooner.
Reasons why numerous species of marine mammals have become threatened or near extinction:
a) SLOW REPRODUCTION RATE: at most only one offspring per year --> difficult to increase pop. size
b) SLOW POPULATION GROWTH: maturing rate of killer whale is 12 years old
c) RETURNING TO SAME GEOGRAPHIC REGION to feed or breed --> easy to capture and exploit
d) LOW POPULATIONS or DISTRIBUTIONS:susceptible to any outside stress such as commercial exploitation
COSEWIC: Committee on the Status of Endangered Wildlife in Canada
EXTINCT: species no longer exists
EXTIRPATED: species no longer exists in the wild in Canada but occurs elsewhere in the world
ENDANGERED: species faces imminent extirpation
THREATENED: species likely to become endangered if limiting factors are not reversed
SPECIAL CONCERN: species is of special concern because of characteristics that make them particularly sensitive
to human activities or natural events
As of 2007, marine mammals make up of 45% of all ENDANGERED species, 50% of all THREATENED species, and 56% of
all SPECIAL CONCERN species.
Total number of mammalian species (land&marine) in brackets
Number of species involved are indicated by X followed by the number.
ex. 2 species of beluga whales are endangered out of a total of 20 mammalian species that are endangered
Extinct(2) Extirpated(3) Endangered(20) Threatened(17) Special Concern(27)
Mink, Sea Whale, Grey x 1 Whale, Beluga x 2 Seal, Northern Fur x 1 Narwhal x 1
Whale, Blue x 2 Whale, Beluga x 2 Otter, Sea x 1
Whale, Killer x 1 Whale, Bowhead x 2 Bear, Polar x 1
Whale, North Atlantic Right Whale x 1 Whale, Fin x 1 Porpoise, Harbor x 2
Whale, North Atlantic Pacific Right x 1 Whale, Humpback x 1 Sea lion, Stellar x 1
Whale, Northern Bottlenose x 1 Whale, Killer x 2 Seal, Lacs des Loup
(Harbor) x 1
Whale, Sei x 1 Walrus, Atlantic x 1
Whale, Beluga x 2
Whale, Bowhead x 1
Whale, Fin x 1
Whale, Grey x 1
Whale, Killer x 1
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in
Extinct(2) Extirpated(3) Endangered(20) Threatened(17) Special Concern(27)
Whale, Sowerby’s
Beaked x 1
Marine mammals make up: 45% all endangered species, 50% all threatened, 56% all special concern
Examples:
EXTINCT: Sea Mink (Neovision Macrodon)
became extinct in 1894 before it could be scientifically described
cousin of American mink, longer bulkier version with longer and coarser reddish pelt
thought to be nocturnal, solitary animal
hunted to extinction by European fur market
DIST.--> along coast of NA ranging from Nova Scotia to New England states.
EXTIRPATED: Atlantic Grey Whale (Eschrischtius robustus)
Department of fisheries and oceans: “Recovery Strategy for the grey whale, Atlantic Population in Canada 2007): re-
covery of the Atlantic grey whale is not feasible at this time ---> species is considered to be extirpated
all other sources of reference consider the grey atlantic species to be extinct
extirpated from western North Atlantic waters since before end of 1800s
medium large baleen whale
would have required northern regions filled with rich food sources, warm and protected lagoons for birth and migratory
pathway (based on pacific grey whales)
unclear why it went extinct, generally accepted that whaling was sole reason responsible
DIST. --> North American seaboard from Florida up into NFL and possibly into Hudson Bay
ENDANGERED: Beluga Whale (delphinapterus leucas)
smaller populations are in danger of being wiped out (the ones on COSEWIC list)
endangered due to commercial hunting carried on in past and have not yet recovered despite ban on whaling
DIST. --> arctic sea. sunpopulations ranging from 40,000 in the Beaufort Sea and 18,000 in eastern Bering sea
--> a highly endangered pop (150-300) in St Lawrence river from comm. hunting and diseases due to toxins
THREATENED: Northern Fur Seal (Callorhinus ursinus)
one of only 2 fur seals in Northern Hemisphere
distinctive feature: small head, short snout, long hind flippers with long digits, hair abruptly stops at wrist
male: dark brown or black. females: dark brown to light grey with light gray/cream stripe on throat/lower chest
male: 2.1 m and females up to 1.5 m
hunted commercially for fur
major threats today: sudden drop in pup survival, competition for food from overfishing, trapped in fish nets
DIST. --> northern Pacific ocean bordered by Sea of Okhotsk (JP), Bering Sea (Russia, Alaska), eastern Pacific (Cali)
--> few breeding sites of coast of russia, alaska, and cali
--> approx. 1.2 million individuals scattered across this range
SPECIAL CONCERN: Atlantic Walrus (Odobenus rosmarus rosmarus)
single species of pinniped family Odobenidae which has upper canine teeth in both sexes
adult males: 3.2m 1200-1500kg. females: 2.7m 600-850 kg
skin 2-4 cm thick and tough. Skin of males thicker and covered in fibrous tubercles around neck as protection from at-
tacks or are visual sexual characteristic
DIST. --> central arctic CA down to NS but pop along atlantic coast of CA extirpated due to comm hunting
--> 5-8 distinct geo subpops 10-15,000 individuals
--> pop that once inhabited Martimes believed to have numbered in tens of thousands but not re-established
despite banning of comm. hunting in CA since 1932
HUNTING/WHALING AND MARINE MAMMALS
estimated 36% of marine mammals are at risk of extinction
History of Hunting
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in
exploitation of marine mammals for OIL, MEAT, BALEEN AND BONES
coastal natives hunted for pinnipeds and near shore cetaceans over 8500 years ago
starting 11th century, commercial hunting seriously reduced population of #s of many species and caused extinction of sever-
al species while others became threatened or endangered
1860s, modern whaling began in NORWAY using motorized boats and harpoon cannons firing grenades
1972, last whaling stations closed in CA and USA
JAPAN and ICELAND (grr..) continue to hunt over 1000 whales or dolphins of various species per year
Examples of extinct species or on their way to extinction:
Stellar’s sea cow extinct by 1768
Atlantic grey whale extinct around early 1700s
Caribbean monk seal rare by 1850s and extinct 1960s
Atlantic Walrus exterminated from eastern Atlantic seaboard by 1800s
Reduced populations:
Sea Otter reduced from 300,000 to several thousand between 1741 to 1900
Fur seals hunted in massive scales resulting in US listing 5 pinniped species as endangered
Cetaceans uncontrolled hunting resulting in US listing 11 as endangered
Whales: over 2 MILLION killed in southern hemisphere during 20th century
PINNIPEDS:
-started with Stone Age people attacking with clubs. other tools: harpoons, gaffs, firearms, nets and traps
-use of firearms increased proportion of “sinking loss”
-hunted for their meat, fat and pelts
-ivory tusk of walrus make them highly prized animals and at least 10,000 walrus are taken per year by natives in arctic
-over 10,000 seals killed every year by natives
-apprx. 100,000 to 200,000 harp seals killed per year by comm. hunters during spring seal hunt along east cost of CA
SIRENIANS:
-Stellar’s sea cow hunted to extinction after 25 years of being discovered. hunted for blubber and strong hides
-slow moving sirenians easy to capture by crews of ships hunting for oil and fur of other m. animals
-native tribes of Africa used manatee hides for shields, hips, flue and dressing for wounds
-Brazil: meat comm. hunted from 1780s to late 1950s. Leather goods made from manatee hides 1935 to 1954.
-underwater explosives have been used to kill them in the past. Now, harpooning them or using nets to trap
-manatee and dugong still hunted today with thousands being taken per year
SEA OTTERS:
-hunted close to extinction for their fur from 1780s to 1911 when they were protected from hunting
-once otters were wiped out in one area, hunters focused on local pops of seals
-most hunting done in boats using harpoons and guns and anchored nets
-Cali: shot from shore. Washington: shooting towers along beaches, natives swim to retrieve
-estimate total pop of sea otters 150,000. annual hunting by abs range 600-1200 per year
POLAR BEAR:
-hunted by Inuit for meat and hides. Non-inuit hunt as trophies
-natives sell hunting permits to sports hunters
-several hundred killed per year using high powered rifles
-estimated global pop. range 25,000 to 40,000
INTERNATIONAL WHALING COMMISSION
from 1911 to 1992, 31 international agreements or treaties ratified: direct protection or management of marine mammals or in-
directly protecting their environment
1948, International Convention for the Regulation of Whaling ratified: one of the most important yet controversial pieces of
legislation that would affect cetaceans --> it established IWC
IWC AIM: “to provide for the proper conservation of whale stocks and thus make it possible the orderly development of the
whaling industry:
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 10 pages and 3 million more documents.

Already have an account? Log in

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
1 Booster Class