Transcript Genetic Diversity and Marine Populations

Threatened and Endangered
Species
Extinction
• Extinction is both a natural and a human
mediated process
• There are temporal and spatial dimensions to
extinction
• Paleoextinctions, which by some are considered
to have occurred more than 400 years ago and
less the result of human activities
• Neoextinctions are within the last 400 years and
are largely due to humans
Marine Paleoextinctions
From Raup and Sepkowski 1984
Extinction
• Extinction can also occur across different
spatial axes
• Local extinction can occur in a small part
of the range
– Salt marsh snail Cerithidea driven extinct in
open mudflat areas, still in vegetated areas
• Regional extinction can occur in large part
of the range
– Extinction of sea otter from large area of
range in north Pacific
– Extinction of gray whales from north Atlantic
Extinction
• Global extinction typically occurs organism is
driven extinct everywhere
– Many examples discussed today
• Commercial extinction
– A species is reduced to the point where it no longer
pays to exploit it
• Functional extinction
– Reduction of species so that it no longer fills its role in
community structure or energy flow
– Example includes loss of baleen whales and increase
in euphausids (krill) in southern oceans
Krill (Euphausa superba)
Blue Whale (Balaenoptera musculus)
Endangered Species Act
• The ESA defines an endangered species
as any species in danger of extinction
throughout all or a significant portion of its
range, and a threatened species as any
species likely to become an endangered
species within the foreseeable future
throughout all or a significant portion of its
range
Endangered Species Act
• Section 4(a)(3)(A) of the ESA requires
that, to the maximum extent prudent and
determinable, NMFS designate critical
habitat concurrently with a determination
that a species is endangered or
threatened.
Recovering Endangered Species
• Recovery targets must incorporate both
the size of the population for “recovery”
and the number of populations of the
targeted size
• Often these data are not used in the final
recovery plan or not used properly
Population Viability
and Recovery Plans
• Biological information is not used as much
expected in recovery plans
• Tear et al. (1993) found that 28% of
recovery plans set the target population
size for recovery at or below the
population size when listed
• 37% of plans set the number of
populations either at or below the number
of populations when listed
Genetics and ESA
• Defining populations and even species is
complicates both listings and recovery
• Molecular tools helped clarify genetic
diversity within species or among closely
related
• These tools have also helped delineate
relationships among higher taxa
• Phylogenies of species may point to
greater need for conserving diversity
Extinct Marine Species
From Carlton et al. 1999
Extinct Marine Species
From Carlton et al. 1999
Extinct Marine Species
From Carlton et al. 1999
Extinct Marine Species
From Carlton et al. 1999
Mammal
Phylogeny
Extinct Mammals
• The New England Sea Mink (Mustela
macrodon) was historically common in
coastal waters
• Hunted for fur as otters and seals
• Larger than any land minks and had pelts
twice as large
• Hunted by indians (in middens)
• Last record was from an island off of
Maine in 1880
Extinct Species
Mustela macrodon
Extinct Mammals
• The largest sirenian was Stellar’s sea cow
Hydrodamlis gigas
• The were huge, as large as elephants (6000 kg
and 8 m long)
• Were found in Bering Sea and northwest and fed
on sea grasses and sea weeds
• Exploited entirely for food for sailors and fur
hunters
• Driven extinct in in 1767 only 27 years after they
were discovered
Stellar’s Sea Cow
Stellar’s Sea Cow Hydrodamlis gigas
Extinct Mammals
• Monk seals area a subfamily of seals with three
widely separated species
• Caribbean monk seal (Monachus tropicalis) was
hunted extensively for fur and for oil in the 18th
century
• Last remaining Caribbean monk seals remained
on the Triangle Keys off the Yucatan
• In 1911, fisherman came and slaughtered all
remaining 200 animals
• Last recorded sighting was in Jamaica in 1952
Endangered Sirenians
• Three species of Trichechus
– Southeastern US, west indies Trichechus manatus
– Amazon Trichechus inunguis
– Tropical west Africa Thichechus senegalensis
• Large (1000 kg and 4 m long)
• Live in groups of up of to 100 or more individuals
feeding on aquatic plants
• Frequent areas of warmer water like power plant
outflows
• Good swimmers (dive 15 minutes), not fast and
frequently hit by propellers
Manatees
Trichechus manatus
Endangered Sirenians
• Dugongs are a single species Dugong
dugon
• They are found along the east coast of
Africa, Red Sea and most of coastal Asia
through the Philippines and Australia
• Large (400 kg and 3.5 m long) but no nails
and have notched tail fluke
• Grazers on plants and shallow divers
• Hunted for meat and leather
Dugong
Dugong dugong
Endangered Monk Seals
• Mediterranean Monk Seal (Monachus
schauinlandis) is the world’s most endangered
pinniped
• Originally found throughout Mediterranean as
well as Black and Mamara Seas, Atlantic coast
of Africa, and Canary and Azores Islands
• Now only two populations remain, eastern
Mediterranean and off African coast
• Mature at 5-6 years and may live 20-30 years
Endangered Monk Seals
• Between 300-500 animals remain
• Listed as critically endangered by IUCN (Intl.
Union for the Conservation of Nature and
Natural Resources) and CITIES (Convention on
Intl. Trade in Endangered Species)
• Threats include deliberately killing, drowing in
fishing gear, pollution, habitat loss
• Also disease and introduced toxic algae
(Caulerpa) also constitute threats
• More than 200 animals died in the summer of
1997 due to disease in the last substantial
colony
Mediterranean Monk Seal
Monachus monachus
Endangered Monk Seals
• Hawaiian monk seal is also highly
endangered
• Primarily found on southwestern sides
(lee) of northwestern Hawaiian Islands
• Occasionally in main Hawaiian islands
• Similar life history as Med monk seal with
one pup per year after maturing 5-6 years
and live 20-30 years
Endangered Monk Seals
• Listed in 1976 under US ESA
(Endangered Species Act) and Marine
Mammal Protection Act
• Primary threats include entanglement in
fishing gear, ciguatera poisoning, sharks
and human disturbance
• Populations are not as critically
endangered as Med Monk Seal as the
result of protections
Hawaiian Monk Seal
Monachus schauinslandi
Extinct Whales
• Of the ten great whale species, none have
been “officially” driven globally extinct
• The Atlantic Gray Whale likely would have
been listed as a distinct species from the
Pacific Gray Whale
• Like Pacific Gray Whales, it fed close to
shore and was easily hunted
• It was driven extinct due to intense
whaling in 1730
Endangered Whales and Dolphins
•
•
•
•
•
•
•
Sei Whale Balaenoptera borealis
Blue Whale Balaenoptera musculus
Fin Whale Balaenoptera physalus
North Atlantic Right Whale Eubalaena glacialis
Beluga Huso huso
Hector's Dolphin Cephalorhynchus hectori
Gulf Of California Harbor Porpoise or Vaquita
(Phocoena sinus)
North Atlantic Right Whale
Eubalaena glacialis
Endangered Sea Otters
• The northern sea otter Enhydra lutris is
endangered and declining
• Historic range was Pacific rim from Japan
to Baja
• Fewer than 2,000 in California and more
than 5,000 in Alaska
• Mature in 3-4 years, live 10-15 years and
typically produce one pup a year
Endangered Sea Otters
• Threatened by killing by fishers and fishing
mortality
• Also diseases
– Acanthocephalan parasites
– Coccidiomyosis
– Toxoplasmosis transmitted from housecats by
kitty litter
• Now threatened in Alaska by Orcas
• Focus of detailed recovery plan
Extinct Sea Birds
• Large flightless bird, the Great Auk (Alca
impennis) was like a northern hemisphere
penguin
• They were hunted heavily by northern fisherman
who identified large rookeries off Newfoundland
• Birds and eggs were hunted (100,000 eggs were
taken on one day)
• After eiders were decimated, auks were hunted
for feathers as well
• Last auks taken off Iceland in 1844
Great Auk
Alca impennis
Extinct Sea Birds
• Many other ocean birds were also driven extinct
• Stellar’s Spectacled Comorant (Phalacrocorax
perspicillatus)
– Large (14 lbs) and almost flightless, they were easy
prey for hunters and fisherman in the Bering Sea
• Bonin Night Heron (Nyctocorax caledonicus
crassirostris)
– Likely driven extinct by hunting and introduced cats
and rats
Extinct Sea Birds
• Tahitian Sandpiper (Prosobonia leucoptera)
– Not collected by hunters
– Likely driven extinct by introduced rats
• Guadalupe Storm Petrel (Oceanodroma
macrodactyla)
– Not hunted because of local tradition
– Adults laid one egg which lay untended during day
while adults were at sea feeding
– Driven extinct in 1911 by introduced cats (so were
40% of other bird species)
Endangered Sea Birds
• Newell's Townsend's Shearwater(Puffinus auricularis
newelli)
• Piping plover ( Charadrius melodus)
• Pelican, brown ( Pelecanus occidentalis)
• Petrel, Hawaiian dark-rumped (Pterodroma
phaeopygia sandwichensis
• Albatross, short-tailed ( Phoebastria (=Diomedea)
albatrus)
• Curlew, Eskimo ( Numenius borealis)
• Rail, California clapper ( Rallus longirostris
obsoletus)
• Rail, light-footed clapper ( Rallus longirostris
levipes)
Endangered and Threatened
Sea Turtles
• All five sea turtles are endangered or threatened
• Endangered turtles
– Hawksbill
– Kemp Ridley
– Leatherback
• Threatened turtles
– Green
– Loggerhead
– Olive Ridley
Kemp Ridley Turtle
Lepidochelys kempii
Endangered Marine Fish
• Atlantic salmon ( Salmo salar)
• Chinook salmon( Oncorhynchus (=Salmo)
tshawytscha
• Sockeye salmon ( Oncorhynchus
(=Salmo) nerka)
• Coho salmon ( Oncorhynchus (=Salmo)
kisutch)
Endangered Marine Fishes
• Southern Bluefin Tuna (Thunnus maccoyii)
• Pondicherry Shark (Charcharhinus
hemiodon)
• Goliath Grouper (Epinephelus itajara)
• Ganges Shark (Glyphis gangeticus)
• Bocaccio Rockfish (Sebastes paucispinus)
Near Extinction
• The barn door skate Raja laevis was once a very
abundant fish
• Large (1.5 m across) and a common item in
bycatch,
• Distributed from (likely) north of Cape Hatteras
to the Grand Banks
• Populations decimated by bycatch in bottom
trawls
• Like several other sharks and skates, this
species on the verge of extinction (Casey and
Myers 1998)
Extinct Invertebrates
• Extinction of Atlantic eelgrass limpet Lottia
alveus alveus in 1929 occurred following
massive dieoff of eelgrass along entire north
Atlantic coast
• Collisella edmitchelli (in NE Pacific) likely due to
habitat loss
• Cerithidea fuscata (in NE Pacific) likely due to
habitat loss
• Littoraria flammea (in NW Pacific) likely due to
habitat loss
Endangered White Abalone
• The white abalone Haliotis sorenseni was
historically abundant from Point Conception to
Punta Abreojos (Baha)
• A deep water species common on rocky reefs
from 25-65 m depth
• Mature in 4-6 years, live 20-30 years and spawn
millions of eggs
• When surveyed in 1970’s after heavy fishing,
densities were 1 per m2 (10,000 per hectare)
• In 1980’s densities were 0.0021 per m2 and by
1992 were 0.0002 per m2 and by mid 1990s were
1 per hectare
Endangered White Abalone
• Current estimates based on recently ROV
(remotely operated vehicle surveys)
suggest that current population size is in
the 1,000 to 2,000 range in about 1000 ha
• On average they are about 50 m apart
from one another (low fertilization Allee
effects)
• Listing under ESA in May 2005 as an
endangered species
White Abalone
Haliotis sorenseni
Extinction Patterns
• Only eight bird and mammal species have
unquestionably gone extinct
• Except for Caribbean Monk Seal (and
Stellar’s Sea Cow), all other extinctions
happened between 1844 and 1913
(Carlton et al. 1999)
What Has Not Gone Extinct
•
•
•
•
Seagrasses
Algae
Fish
Great Whales (possible exception)
Threats on a Global Scale
• Coral reefs contain much of the world’s marine
diversity
• Recent studies (Bryant 1998) suggest that 5% of
the world’s reefs are now degraded and no
longer functioning
• 30% of the world’s reefs are heavily degraded
and could be lost in the next 10-20 years
• You can calculate expected losses based on
species-area curves which links loss of species
to habitat
• This would mean that almost 10% of the world’s
coral reef species could be lost