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Bream Lab: Relative Weight

Bream Lab: Relative Weight. BIOL 3500L Dr. Christopher Kodani. Learning Objectives (for Lab Quiz). Calculate relative weight Explain: Relative weights, below 0.8, from 0.8 to 1.0, above 1.0 Why using fish board is important Discuss example from Florida Fish & Wildlife

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Bream Lab: Relative Weight

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  1. Bream Lab: Relative Weight BIOL 3500L Dr. Christopher Kodani

  2. Learning Objectives (for Lab Quiz) • Calculate relative weight • Explain: • Relative weights, below 0.8, from 0.8 to 1.0, above 1.0 • Why using fish board is important • Discuss example from Florida Fish & Wildlife • Identify largemouth bass, bluegill, warmouth, redbreast sunfish, channel catfish • Discuss linear and non-linear regression

  3. Shelford’s Tolerance Curve • Note Y-axis “Performance” • Could be some measure of condition: • Speed of animal • Height of plants • # of offspring

  4. Relative Weight • For fish, condition measured as “Relative Weight” • Ratio of actual weight to standard weight • Similar to “Body Mass Index” for humans • CDC website http://www.cdc.gov/nccdphp/dnpa/bmi/adult_BMI/about_adult_BMI.htm

  5. Standard Weight • What a fish “should” weigh • Depends upon • Size of fish • Species • Other factors (region, sex, reproductive condition) • Available in literature • Georgia Adopt-a-Lake Manual • Alabama Cooperative Extension http://www.aces.edu/pubs/docs/A/ANR-1193/

  6. Fish Measurements • Florida Fish and Wildlife http://floridafisheries.com/Fishes/measure.html • Ignore girth, we only want length • Use fish board!

  7. Calculating Relative Weight • Actual weight / standard weight • If you like, you can x100 for percentage

  8. Identifying Fish • These could be present in Swan Lake: • Channel Catfish • Look like a cat! • Largemouth Bass • Two distinct dorsal fins • Sunfishes a.k.a. “bream” (two dorsal fins merged) • Bluegill • All black ear tab • Redbreast sunfish • Has very long ear tab • Warmouth • Stripes on face

  9. Fish ID Study Resources • Texas Parks http://www.tpwd.state.tx.us/landwater/water/aquaticspecies/inland.phtml • Virginia Fish & Wildlife http://www.cnr.vt.edu/efish/families/centrarchidae.html • NC State University http://www.ces.ncsu.edu/nreos/wild/fisheries/topics/fishidentification.html • Tennessee Wildlife Resources Agency http://www.ces.ncsu.edu/nreos/wild/fisheries/topics/fishidentification.html • Florida Fish and Wildlife http://www.ces.ncsu.edu/nreos/wild/fisheries/topics/fishidentification.html

  10. Actual Research Example • Florida study shows flooding may improve some fish’s condition • Florida Fish and Wildlife http://www.floridamarine.org/features/view_article.asp?id=24545 • Note box and whiskers plot

  11. For Your Notebooks • Frequency Distribution Tables (separate species) • Body mass • Total length • Relative weight • Make histograms (separate species) • One for length • One for body mass • Scatter Plot (all fish on one) • Mass vs. length • Plus standard lab write up in your notebook, by next lab (10 points)

  12. Frequency Distribution • An organized, summarized list of measurements • Tells number within each interval • Ex: Ages of people in a group

  13. Frequency Distribution Example • Bluegills (cm): 8.83, 9.25, 8.77, 10.38, 9.31, 8.92, 10.22, 7.95, 9.74, 9.51, 9.66, 10.42, 10.35, 8.82, 9.45, 7.84. 11.24, 11.06, 9.84, 10.75

  14. Histogram

  15. Scatter Plot

  16. Mean • Mean = average • Not the only measure of centrality! • Also median and mode! • Example • Bluegills (cm): 8.83, 9.25, 8.77, 10.38, 9.31, 8.92, 10.22, 7.95, 9.74, 9.51, 9.66, 10.42, 10.35, 8.82, 9.45, 7.84. 11.24, 11.06, 9.84, 10.75

  17. Mode • Mode = most common category • Bluegills (cm) • 8.83, 9.25, 8.77, 10.38, 9.31, 8.92, 10.22, 7.95, 9.74, 9.51, 9.66, 10.42, 10.35, 8.82, 9.45, 7.84. 11.24, 11.06, 9.84, 10.75

  18. Median • Median = the “middle one” (for odd sample size) • Or average of the two in the middle for even sample size

  19. Regression • Makes a “best fit” line for data • We can use MS Excel’s Graph Wizard function • Enter length into column A • Enter body mass into column B • Use Graph Wizard to graph of bluegill weight vs. length

  20. Linear vs. Non-Linear Regression • Linear regression • Assumes straight-line relationship • y = mx + b • Non-linear regression • Uses other equations for line • Y = a + bx + cx2 • In Excel, click on line • Add trendline • Choose linear or power • Options: • Show equation • Show r2

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