HC BIOL 103 - Current State of Our Orcas

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Current State of Our OrcasKiller Whales- OrcasOrca BiologyOrca Natural HistoryTransient vs. Resident OrcasResident OrcasSouthern Resident OrcasDead OrcasState of Southern Resident OrcasPuget Sound Orcas and PCBsPolychlorinated Biphenyls (PCBs)PCBsEcosystem ReviewGeneralized Ecological PyramidIdealized Puget Sound Ecological PyramidPollutantsFactors Influencing Impact of PollutantsPollutants in the Food ChainDDT in a Long Island Estuary (from Woodwell, Wurster and Isaccson, 1967)Idealized Puget Sound Pyramid With PCBsThe ‘Double Whammy’Current State of Our OrcasHighline Community CollegeKiller 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 eyesOrca 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 yearsOrca Natural History•Found in all the world’s oceans•Travel in pods from 3 to >150 members•Feed on fish, squid and marine mammalsTransient vs. Resident OrcasTransients ResidentsHabitat Offshore NearshoreFood Marine MammalsFishPod Size 3-5 >20Vocalization Quiet Very VocalResident 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 OrcasSouthern 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 whereDead 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 sedimentsPolychlorinated Biphenyls(PCBs)ClClClClPCBs•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 1977Ecosystem 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 memberGeneralized Ecological Pyramid2° Consumers3° Cons.1000 g Biomass100 g 10 g 1 g Primary ProducersPrimary ConsumersIdealized Puget Sound Ecological Pyramid1000 g 100 g 10 g 1 g PhytoplanktonZooplanktonSalmonOrcasPollutants•Pollutant–Adversely affects the health, survival, or activities of living organisms–Persistent Organic Pollutant•POP•Stable, Long Lasting•Includes DDT and PCBsFactors 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 doPollutants 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 transferredDDT in a Long Island Estuary(from Woodwell, Wurster and Isaccson, 1967)Trophic level Organism DDT in wet weight of whole organismPrimary ProducerGreen Alga 0.08 ppmPrimary ConsumerMud Snail 0.26 ppmSecondary ConsumerSummer Flounder1.28 ppmTertiary ConsumerRing-billed Gull75.5 ppm (1000x initial concentration)Idealized Puget Sound PyramidWith PCBs1000 g 100 g 10 g 1g PhytoplanktonZooplanktonSalmon1 g Trophic Level %PCBPhytoplankton 0.1%Zooplankton 1%Salmon 10%Orcas 100%OrcasThe ‘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


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HC BIOL 103 - Current State of Our Orcas

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