THE PREFERENCE OF ZEBRAFISH (Danio rerio) ON SPECIES WHILE SCHOOLING
...but they can produce fertile offspring when mating with a zebrafish (giveusahome.co.uk). In our experiment we will be observing whether zebrafish prefer to school with their own species or leopard danios. OBJECTIVE AND HYPOTHESIS The objective of this experiment is to determine whether zebrafish have a preference on the species which they school with. This will be determined by the time in minutes they spend either near their own species or of that of the leopard danio. Null Hypothesis: There will be no difference in the amount of time in minutes the zebrafish spends near the same species or the leopard danio. Alternative Hypothesis: There will be a difference in the amount of time the zebrafish spend close to their own species and the time they spend close to the leopard danio. MATERIALS AND METHODS In our experiment each of the side tanks was set up with five fish, one side with conspecific fish and the other side with the leapord danio. The focal fish used is the zebrafish for each replicate. We set up our experimental replicates using the procedure as described in our lab handout. The focal fish was different for each of the six replicates and was given five minutes of acclimation time and then observed for ten minutes. There were four people timing, two were timing the quarters and the other two were timing the halves. The timing began as soon as the fish’s eyes crossed the line dividing the sections. The side tanks were switched after three trials to avoid any errors. RESULTS In this experiment each focal fish acted different while in the middle tank, in table A the observations that were made during each replicate are listed. Our results showed that the mean time was greater on the half and the quarter with the conspecific species. These results are shown in Graph 1 and in Graph 2. We compared our results using a t-test, which the equation is listed below. The t calculated value for the quadrants is .8378 and the t calculated for the halves 5.242 the degrees of freedom used was 10 so the t-critical is 2.228. DISCUSSION From this study it can be concluded that zebrafish do not have a preference on the species they school with. The null hypothesis can be accepted when looking at the quadrants, which means there is no significant difference between the time the zebrafish spent closest to either species. This was accepted because the t-calculated is less than the t-critical. The alternative hypothesis can be accepted when comparing the halves that the zebrafish preferred with respect to the species. The alternative can be accepted because the t-calculated is greater than the t-critical. This experiment may have had error since there were barriers between the fish which may have prevented them form interacting with either of the other species. There also could have been error in the timing since at time it could be hard to determine what half or quarter the zebrafish was on. The study could also be modified to include other species that...