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Pinnipeds: Seals true seals Sea lions, fur seals eared seals Walrus 35+ species globally Galápagos fur seal (40 – 140 lbs) Southern elephant seal (800 – 8,000 lbs) Differing life strategies: Shore-based breeding ice-based breeding resident / migrating Diet: fish, shellfish, squid, birds Steller sea lion - Prince William Sound, AK
Fin-footed facts: Dives to 1,700 m depth Northern elephant seals Dives of 1 ½ hours Weddell seals Bi-annual migrations Northern elephant seals swim 20 – 40,000 km / yr Highly variable suckling period (lactation) 1-3 years - Galápagos fur seal % milk fat 4-8 days - Harp seal up to 60% milk fat Weddell seal sleeping in ice hole Ross Sea, Antarctica
Pinnipeds in Oregon: Harbor seals Northern elephant seals Steller sea lions California sea lions males outside of breeding season Very rare visitors: Northern fur seals Guadalupe fur seals
Seguam Island, Aleutian Islands, AK July 1970 Steller sea lions
? ? ? ? ?? ? Steller sea lion The largest of the ‘eared seals’ – otariids Males: - 2,500 lbs defend territories June - August Females: up to lbs Seguam Island, Aleutian Islands, AK July 2007
For more information about Steller sea lions, students can read the profile about “Stella” the Steller sea lion at : es/Stella.pdf es/Stella.pdf
, Steller sea lions counts in Western Alaska 1970’s: > 170, : 45,000 endangered Source: NMFS Endangered Species Act listing & unexplained decline has led to severe restrictions on largest commercial fishery in US (Alaskan groundfish) The problem : Steller sea lion population 1970’s to 2007
, Eastern Steller sea lions counts including Oregon, CA, WA, BC, SE-AK 1970: 20, : 46,000 threatened Steller sea lion population 1970’s to 2007 Steller sea lions counts in Western Alaska 1970’s: > 170, : 45,000 endangered Source: NMFS
ESA listing & unexplained decline: severe restrictions on largest commercial fishery in US (Alaskan groundfish) How do scientists count sea lions? Sounds easy, right? Yo, watch out!
Telemetry is the science and technology of measuring things remotely that allows information to be obtained by a wire, radio, satellite, data recorder or other device such as a tag. Scientists use telemetry to study animals remotely
How Satellite Telemetry in Steller Sea Lions Works
Temperature tells how the sea lion died A slow gradual decrease in temperature indicates death by natural causes. A dead body is a cold body.
Temperature tells how the sea lion died A rapid decrease in temperature in a short time indicates death by a predator.
The tag stays in dead body that slowly cools. The tag comes out of the body into the cold water when dismembered by a predator. Death by Starvation or DiseaseDeath by Predation
From earlier research: Scientsts know 70% of weaned* animals die before the age of 5, but they did not know how they were dying Research results since 2005: 36 young sea lions released with LHX tags in Prince William Sound 12 animals died How did they die? What have we learned? Mortality
Conclusion since 2005: At least 11 of 12 died by predation Transient killer whales are likely responsible for the majority of deaths in young Steller sea lions What have we learned? Evidence for killer whale predation: Killer whales were video recorded in Resurrection Bay. Researchers found a killer whale with 14 flipper tags (external markers) from Steller sea lions in its stomach. Killer whales typically dismember (break apart) their prey. Mortality
The Life History Transmitter Scientists and engineers are designing a new LHX2 Tag Half the size of the old LHX1 tag Can detect births using the animal’s body temperature Productivity
Temperature can be used to detect births. Temperature and Dive Pattern in A Sea Otter Productivity
Population Ecology A population is a group of individuals of the same species living in the same region. Population ecology is the study of how populations change over time and interact with their environment.
Population Ecology Change in Population = (Births – Deaths) + (Immigration – Emigration) Change in Population = (Births – Deaths) + (Immigration – Emigration) At the basic level, scientists studying animal population growth ask: o How many are born? o How many die? o How many animals move into the same region (immigration) ? o How many animals move out of the same region (emigration) ?
Carrying Capacity A population’s size is limited by its carrying capacity: the maximum, stable population an environment can support over a long period of time. The carrying capacity indicates how well the environment is able to support animals with food, habitat, territory, and other resources.
Population Density the number of animals per area As numbers increase, the share of the food (or other resources) gets smaller. ½ each¼ each population density affects population growth due to the availability of resources
Aerial photos for estimating populations Counting all 45,000 animals would take forever, so scientists estimate the population size by counting a sub-sample of the population (yellow square).
Mark Recapture Another method for estimating population size Scientists capture animals, mark them, and resample to see what percent of animals have marks. cap.swfhttp://www.biologycorner.com/flash/mark_re cap.swf
Engineers and Scientists Worked as a Team to Design the LHX Tag The scientist (customer) sets the criteria for the tag The engineer designs the tag (product)
Scientists ask questions and find answers to them by doing research to discover the answer. How are science and engineering different? Engineers develop things (technology) to address human needs or “problems”.
How do engineering and science compare? EngineeringScience Identify NeedState your question Do background research Establish design criteriaFormulate hypothesis, identify variables Prepare preliminary designDesign experiment, establish procedure Build and test a prototypeTest your hypothesis by doing an experiment Test & redesign as necessaryAnalyze your results & draw conclusions Present results after
Engineering Process Cycle from NASA: Plan, do, reflect, review
The Engineering Process Identify the need: –How can I design a ______ that will ______? For example, how can I design a transmitter that will float and be able to send a signal? Identify criteria (requirements) and constraints (limitations): requirements: It must float 3 cm above the water. constraints: It must be stable in water, cannot tip.
The Engineering Process Brainstorm solution: Quickly sketch ideas as the group discusses ways to solve the problem Plan: Draw a scale diagram of each idea (top, front, side and 3-versions).
The Engineering Process Create: Choose the best idea. Describe why, including criteria and constraints.* Improve: Examine and evaluate the product based on the criteria and constraints.
Criteria Design Specifications
Design Constraint Table Where Stellers liveConstraintsWhyWhat happens in oceanwaterproofElectronics cannot get wettag shorts out on landwithstand temperature changeselectronicstag will not work at cold temperaturesfunction in the coldelectronicstag will not work salty environmentrustproof (non-corrosive)so it will not rustleakage What they do eat, feed on fishnot interfere with feedingavoid harm to animal have youngnot interfere with reproduction or birthavoid harm to animal dive (pressure)be ble to withstand high pressuresea lions dive to 500mtag explodes come out on landbe able to withstand pressure changescan cause tag fatiguetag breaks swimwaterproofElectronics cannot get wettag shorts out LHX goes inside the body Shapeno sharp edges or point tipscan harm animal Sizenot too largeavoid harm to animal Materialscompatible with bodyavoid harm to animaltoxicity or immune response LHX Comes out of body Appearancehas to be visible by peopleSo scientists can recover tag Buoyancymust floatto transmit signal to satellite Power sourceneeds batteriesto transmit signal to satellite
How many batteries? 5 th -8 th Apply the principles of buoyancy to design their own “transmitter”. is a force exerted by a fluid, that opposes an object's weight Buoyancy :
Picture of Buoyancy Setup
Learning Procedure Students use the formula for the volume of a cylinder to calculate the water displacement due to buoyancy. Students use the water displacement weight to calculate the number of batteries (pennies) to put in the “tag” for a given amount of floatation. Students as engineers, test their calculations with the model Teachers and students engage in a discussion of tradeoffs.
Formulas/Information Volume of cylinder (V) = Pi r 2 x height Mass, m = pV p = density of water 1g/cm 3 Weight of tube = 22.1g Weight of battery2.5g
Electromagnetic Shielding 9 th -12 th Test the principles of electromagnetic shielding using a cell phone. external electrical field causes the charges to rearrange, which cancels the field inside Faraday’s Cage
Picture of Faraday’s Cage Setup
Learning Procedure 1. Introduce electromagnetic radiation, how cell phones work, and Faraday’s cage. 2. Ask if radio waves can travel through tissue. Ask students how they would test this. 3. Ask students to predict what will happen to the signal strength (number of bars) of a transmitter in air, in a Faraday’s cage, and under saltwater. 4. Challenge students to think about how they would design a room that would prevent cell phone signals.
Jo-Ann Mellish (Alaska Sea Life Center), Roger Hill (Wildlife Computers) Photo credits: Alaska Dept. Fish & Game, Jason Waite Funding through: North Pacific Marine Research Program The National Science Foundation NMFS Permits # , Acknowledgements, Permits