Somethings Fishy LAAB
Purpose: The purpose of this lab is to see how the mark-recapture method is used in real life to measure populations in real ecosystems. Aside from that, the mark-recapture technique will be compared to other methods of population estimating Background: Sampling is a technique sometimes used to estimate the size of a population. In sampling, organisms in a small area are counted and representative of the entire area. Another method commonly used is known as "tagging." The tags can be stickers, ear clips, or notches. These tags can track migration patterns, health, and range and help to estimate population sizes. Scientists would let tag some of that population then release those animals to naturally spread. By taking random samples and determining the percentage tagged from that random sample, scientists can hypothesize the population in that area Procedure:
1. Obtain a bowl with your “species” in it. (“fish” crackers).
2. Do NOT count the number of fish in your pond yet!
3. Have one member of your group remove a large handful of fish. Write that number here: 32
4. Count the number of fish you just removed and replace these fish with “tagged” fish (in this case,
colored “fish”)
5. Mix your pond well to redistribute the tagged fish among the other fish.
6. One member at a time (and without looking), remove a handful of fish and record the number of total
fish in the sample, the number of “tagged fish”, and figure out the percentage of tagged fish. (see chart)
7. Return your handful to the bowl!! Continue with this until you have taken 20 samples. Data
1. Obtain a bowl with your “species” in it. (“fish” crackers).
2. Do NOT count the number of fish in your pond yet!
3. Have one member of your group remove a large handful of fish. Write that number here: 32
4. Count the number of fish you just removed and replace these fish with “tagged” fish (in this case,
colored “fish”)
5. Mix your pond well to redistribute the tagged fish among the other fish.
6. One member at a time (and without looking), remove a handful of fish and record the number of total
fish in the sample, the number of “tagged fish”, and figure out the percentage of tagged fish. (see chart)
7. Return your handful to the bowl!! Continue with this until you have taken 20 samples. Data
Questions: 1. What is the mean (average) of your percent tagged fish from your 20 samples?
43% 2. Using the following formula, determine an estimated population for you pond: 71 Fish
Population size = total number captured x number marked
total number captured with mark
3. Now, actually count the number of fish in your bowl: 73 4. Find you percentage error by using the following formula: 2.74%
100 x (your estimate of population - actual size of population) / (actual size of population)
5. What concerns should a biologist have about a species' habits before (s)he uses this method to approximate the size of a population?
We fulfilled of purposing by estimating the population by using the mark-recapture technique. We tagged a handful of fish and release them into the pond. We took random sampling 20 times and calculated the total amount of fish from that. From this lab, I learned how to estimate a population in an area by using the mark-recapture technique to do so.
43% 2. Using the following formula, determine an estimated population for you pond: 71 Fish
Population size = total number captured x number marked
total number captured with mark
3. Now, actually count the number of fish in your bowl: 73 4. Find you percentage error by using the following formula: 2.74%
100 x (your estimate of population - actual size of population) / (actual size of population)
5. What concerns should a biologist have about a species' habits before (s)he uses this method to approximate the size of a population?
- Migration
- Hibernation (Being dormant for a long period of time)
- Good camouflage
We fulfilled of purposing by estimating the population by using the mark-recapture technique. We tagged a handful of fish and release them into the pond. We took random sampling 20 times and calculated the total amount of fish from that. From this lab, I learned how to estimate a population in an area by using the mark-recapture technique to do so.