Crayfish Population Relations

The group
James, Jacob, Katana, Kyle, Travis, John, Mara and Charlie

Movie
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The Question: How does crayfish population and size change as we move down stream.


The Hypothesis: As we move downstream the population and size would decrease.

Background Information: We  already knew what areas of the stream were moving faster or slower, where the sunlight hit it, and the depth of the water.

How did we test our hypothesis:

                Materials: Nets, buckets, ruler, sticks, field books.
                                                                                  crayfish_bucket

                The process:  
                                        1. The first we caught the crayfish.
                                              This was done in a number of methods. One method we would put the net behind the crayfish then either poked at or splashed water at the crayfish to scare it into the net.   Another method that was used was quickly do a coop from above and quickly put it back up. This was the most difficult method to use. The last method we used was graping it with our hands. This was the most effective method used if the person was not afraid to get pinched by it.


                                                                                     holding_sticking


                                        2.  Then we would measure them by putting them on the ruler. We measured (inches) from the top of the head to the tip of the tail.

                                       3. We recorded the size of the crayfish and where it was found in a hand drawn map in one of our field books.
                                       4. We put the crayfish safely into a bucket of water.
                                       5. We caught as many crayfish as we could in the amount of time we had (about 40 min..)
                                       6. After our time was up we put all the crayfish back into that part of the stream.

              The data:

                                  Area 1.

                                                                      area1


                                                   Map
                                        map_1
Crayfish 1
 2
 3
 4
 5
 6
 7
 8
 9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
Size (in.)
 3
 1.75
 2
 2.5
 2.5
 2
 2.25
 2.5
 2
 2
 2.25
 2.25
 2.25
 2
 2
 2.5
 1.75
 2.5
 2.25
 2.5

 
Crayfish
 21
 22
 23
 24
 25
 26
Size (in.)
 2.25
 1.785
 2.5
 2
 1.5
 2


                    Area 2  
                                                                      area2
                                      Map
                                                            Map_2

Crayfish
 1
 2
 3
 4
 5
 6
 7
 8
 9
 10
 11
 12
 13
 14
Size (in.)
 2.75
 2.25
 2.25
 2.5
 2.25
 2.25
 2.25
 2.625
 2.5
 2.25
 2
 2.5
 2.5
 1.75



                     Area 3

                                                                   area3

                                      Map
                                                 Map_3

   
Crayfish
 1
 2
 3
 4
 5
 6
 7
 8
 9
 10
 11
 12
 13
 14
Size (in.)
 2.5
 2
 2
 2
 1.75
 2
 2
 1.75
 1.75
 2.25
 2.75
 2.5
 2.5
 2.25


          * In the third area we did not have as much time to thoroughly collect enough of the crayfish. when we left we know that there were plenty more there because there were quite a few that we attempted to catch but missed.

           Conclusion : As we moved down stream the amount of crayfish did not decrease and the size did not decrease either.

          Additional conclusions: Although there was not a decrease of crayfish as we moved downstream there were larger groups of them in warmer water of the sun. Also it seemed to be that in the deeper pools of calm water were larger crayfish, on average.

         What we learned about east woods: We learned that crayfish populations do not rely on the position but whats in each area of the Brook.

    



                                                                                          jacob_crayfish