Catch & Release Lab
Problem
What is the best estimated population size produced by the catch and release method?
Hypothesis
A sample catch of 10 for a total of 15 catches will produce the most accurate estimate of the population size.
Parts of the Experiment
Independent Variable: number of fish tagged, number of catches
Dependent Variable: percent of each fish tagged after each catch, estimated population size
Experimental Group: Every group in the class
Dependent Variable: percent of each fish tagged after each catch, estimated population size
Experimental Group: Every group in the class
Materials
1 Brown Paper Bag
Beads of two colors
Beads of two colors
Procedure
1) Take a sample catch of either 10, 20, or 30 beads from ocean bag.
2) Replace them with a different color of beads.
3) Shake the bag and take a sample catch from bag.
4) Record the number of fish tagged in the sample, total sample size, and percent tagged.
5) Repeat step 3 and 4 for 10, 15, or 20 catches.
6) Calculate the average percent tagged and estimated population size. Then count the actual population size and record it.
7) Calculate the percent of error between actual population size and estimate population size.
8) Compare with others data.
2) Replace them with a different color of beads.
3) Shake the bag and take a sample catch from bag.
4) Record the number of fish tagged in the sample, total sample size, and percent tagged.
5) Repeat step 3 and 4 for 10, 15, or 20 catches.
6) Calculate the average percent tagged and estimated population size. Then count the actual population size and record it.
7) Calculate the percent of error between actual population size and estimate population size.
8) Compare with others data.
Observations
The catch size of 10 with 20 catches had a 22.8% of error. When compared to the rest of the class, the sample catch did not show accurate results. Out of the entire class, a catch size of 20 with 20 catches produced the most accurate results with a 0.5% of error and a catch size of 30 with 15 catches produced the least accurate results with a 124% of error.
Data Table and Graphs
data.docx | |
File Size: | 31 kb |
File Type: | docx |
Analysis and Conclusions Specific to the Lab
1) The estimated population size is mostly likely different from the actual population size due to the fact that the factors that affect population size are not calculated in with estimate. These factors include birth rate, death rate, immigration, emigration, total fertility rate, life expectancy, diseases, and the number of females and males.
2) If the size of the catches was very low or too high, then estimated population would be very below or above the actual population.
3) The more samples taken causes an increase in the percentage of error.
4) This method is not an effective way to assess population because the percentage of error will always vary and in order to have accurate results there would have to be various people testing different sample sizes and number of catches.
5) If your predicting a large population, the percentage of error would be large because the sample sizes and number of catches would be larger.
6) The biologist is going to have to be concerned about how big the species' habitat is, whether or not the habitat is being destroyed or affected by other species, and also if there is enough resources to sustain the population.
2) If the size of the catches was very low or too high, then estimated population would be very below or above the actual population.
3) The more samples taken causes an increase in the percentage of error.
4) This method is not an effective way to assess population because the percentage of error will always vary and in order to have accurate results there would have to be various people testing different sample sizes and number of catches.
5) If your predicting a large population, the percentage of error would be large because the sample sizes and number of catches would be larger.
6) The biologist is going to have to be concerned about how big the species' habitat is, whether or not the habitat is being destroyed or affected by other species, and also if there is enough resources to sustain the population.
General Analysis and Conclusions
The lab went as planned but my hypothesis was not correct. When we compared our data with the rest of the class, we found that a sample size of 20 with 20 catches produced the most accurate results. Although that sample produced the most accurate results, we should have included all the factors that affect population in the calculations to make the results even more accurate. Also, the lab would have been more accurate if we did it over a longer period of time. This lab taught me that many factors like birth rate, death rate, health and etc. affect population, but in a recent study in the UK, scientists found that the mode of birth and a country's access to the methods also affects the population demographic. Scientists are still studying the UK's population to see if there any other factors affecting the demographic.
Walsh, Caitlin. "Study suggests demographic factors can predict risk of operative births in UK women ." EurekAlert. AAAS, The Science Society, 20 Mar. 2013. Web. 20 Mar. 2013. <http://www.eurekalert.org/pub_releases/2013-03/w-ssd032013.php>.
Walsh, Caitlin. "Study suggests demographic factors can predict risk of operative births in UK women ." EurekAlert. AAAS, The Science Society, 20 Mar. 2013. Web. 20 Mar. 2013. <http://www.eurekalert.org/pub_releases/2013-03/w-ssd032013.php>.