current state of our orcas highline community college
TRANSCRIPT
Current State of Our Orcas
Highline Community College
Killer Whales- Orcas
• Orcinus orca
• Largest member of the dolphin family, Delphinidae
• Identifying traits– Tall dorsal fin– Saddle patch behind dorsal fin– White patches on sides, belly and behind eyes
Orca Biology
• Average Birth Weight: 395 lbs
• Average Adult Weight: 2.6 – 9 tons– Males are larger than females
• Lifespan:– Males ~40 years– Females >60 years
• Sexually mature ~13 years
Orca Natural History
• Found in all the world’s oceans
• Travel in pods from 3 to >150 members
• Feed on fish, squid and marine mammals
Transient vs. Resident Orcas
Transients Residents
Habitat Offshore Nearshore
Food Marine Mammals
Fish
Pod Size 3-5 >20
Vocalization Quiet Very Vocal
Resident Orcas
• Resident orcas live in coastal areas feeding mostly on fish
• Live in extended familial units called pods– Pods are matriarchal
• Northeast Pacific resident orcas are found from Puget Sound to Alaska– Puget Sound orcas are Southern Resident Orcas
Southern Resident Orcas
• Consists of three pods: J, K and L
• Summer in the area around the San Juan Islands feeding on salmon runs
• Winter on outer coast, but do not know where
Dead Orcas
State of Southern Resident Orcas
• Almost 20% orcas died between 1995 and 2000.
• Reproductive females have not produced young in ten years.
• Only four adult males in the entire community of 80 whales.
Puget Sound Orcas and PCBs
• Highest levels of PCBs in blubber of any marine mammal in the world– Average almost 150 ppm
– <10 ppm PCB is known to cause immune problems in seals
• Dead female transient orca on Dungeness Spit in May 2002 – 1000 ppm PCB
– 12ppm- EPA’s standard for marine sediments
Polychlorinated Biphenyls(PCBs)
Cl
Cl
Cl
Cl
PCBs• Highly stable oily fluids and solids
– Transformers, pesticides, etc
• Fat soluble – Reside in fatty tissue
• Block hormone activity– Destroy normal immune function– Cause liver cancer, pituitary tumors, leukemia, and lymphoma
• Banned in U.S. since 1977
Ecosystem Review
• Ecosystem– Organisms interacting with environment and
each other through a food chain
• Food Chain – Biomass moves from one organism to
another as each eats a lower member and, in turn, is eaten by a higher member
Generalized Ecological Pyramid
2° Consumers3° Cons.
1000 g Biomass
100 g
10 g
1 g
Primary ProducersPrimary Consumers
Idealized Puget Sound Ecological Pyramid
1000 g
100 g
10 g
1 g
PhytoplanktonZooplanktonSalmon
Orcas
Pollutants
• Pollutant– Adversely affects the health, survival,
or activities of living organisms
– Persistent Organic Pollutant• POP• Stable, Long Lasting• Includes DDT and PCBs
Factors Influencing Impact of Pollutants
• Solubility– Water soluble pollutants
• Move easily through environment
– Fat soluble pollutants• Need a carrier • Long-lasting in body’s fatty tissue
• Persistence– More stable– Longer to break down– More harm it can do
Pollutants in the Food Chain
• Bioaccumulation– Cells increase the concentrations of molecules
relative to the environment
• Biomagnification– Concentration of pollutants increases as they
move up the ecological pyramid– Only 10% of biomass, but most of the pollutant
is transferred
DDT in a Long Island Estuary(from Woodwell, Wurster and
Isaccson, 1967)
Trophic level Organism DDT in wet weight of whole organism
Primary Producer
Green Alga 0.08 ppm
Primary Consumer
Mud Snail 0.26 ppm
Secondary Consumer
Summer Flounder
1.28 ppm
Tertiary Consumer
Ring-billed Gull
75.5 ppm (1000x initial concentration)
Idealized Puget Sound PyramidWith PCBs
1000 g
100 g
10 g
1g
PhytoplanktonZooplanktonSalmon
Orcas
1 g
Trophic Level %PCBPhytoplankton 0.1%Zooplankton 1%Salmon 10%Orcas 100%
The ‘Double Whammy’
• In blubber, PCBs are not very harmful.
• Low salmon runs force orcas to metabolize more blubber to survive.
• The blubber releases PCBs into the blood, destroying the immune system.
• Therefore, starvation increases the lethality of the pollutant.
Sources of Pollutants in the Environment
• Point Source– Specific location of concentrated
pollutants• Factory waste• Sewage
• Nonpoint Source– Scattered or diffuse sources of pollutants
• Golf courses• Agriculture