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

From Raup and Sepkowski 1984

Marine Paleoextinctions

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

Mustela macrodon

Extinct Species

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