The Humboldt Penguin Egg Quality Study

Problem:

.........Of the Mysis relicta population at the Columbus Zoo and Aquarium will the Mysis relicta sample consuming Brine shrimp nauplii have higher reproduction rates than the Mysis relicta sample consuming Rotifers?

Subjects

(Mysis relicta Population at the Johnson's Aquatic Complex)

Hypotheses:

.........Null Hypothesis (mean):
..................H0: Mysis relicta consuming Brine shrimp nauplii will have a lower mean adult to juvenile ratio then Mysis relicta consuming rotifers.

.........Alternative Hypothesis (mean):
..................H1: Mysis relicta consuming Brine shrimp nauplii will have a higher mean adult to juvenile ratio then Mysis relicta consuming rotifers.

.........Null Hypothesis (variance):
..................H0: Mysis relicta consuming Brine shrimp nauplii will have a lower variance in their adult to juvenile ratio then Mysis relicta consuming rotifers.

.........Alternate Hypothesis (variance):
..................H1: Mysis relicta consuming Brine shrimp nauplii will have a higher variance in their adult to juvenile ratio then Mysis relicta consuming rotifers.

Statistical Test:

.........The statistical tests conducted were a z-test of independent sample means and an f-test of independent sample means. The z-test was conducted on the mean Propagation rates of Mysis relicta consuming Brine Shrimp nauplii, and Mysis relicta consuming Rotifers. The same test was run for variance (f test). This study was conducted at a confidence interval of 95%

Abstract:

........ The Zoology students at the Columbus Zoo School program, in conjunction with the Columbus Zoo School staff were asked to conduct a study on the Mysis relicta population at the Columbus Zoo and Aquarium, which are the main food source for the Phycodurus eques on exhibit at the Johnson’s Aquatic Complex. This study, along with previous ones conducted on the Mysis relicta have been in an effort to identify the ideal variables for Mysis relicta propagation rates. The current food source for the Mysis relicta are Brine Shrimp nauplii. This year a new food source, rotifers, were introduced to the Mysis relicta population and the keepers at the Columbus Zoo and Aquarium were eager to contrast the two food sources. A study was completed on which food source encouraged the highest propagation rates and gave the highest population levels. The Mysis relicta population used for the study are located in the Johnson’s Aquatic Complex at the Columbus Zoo and Aquarium and are not on exhibit unless being distributed into the Phycodurus eques exhibit as a food source. The adult Mysis are separated from the nauplii and left to reproduce in open water as they would in a non-captive/controlled environment.

Movies:

Mysis relicta Propagation Study

Conclusion:

.........There were two separate hypothesis used in this study to assist in determining which food source produced the highest propagation rates within the Mysis relicta populations at the Columbus Zoo and Aquarium. One for mean and one for variance. The results of this study support the rejection of the null hypothesis in favor of the alternate hypothesis for sample variances. The Mysis relicta consuming Rotifers reproduced at a steadier, more reliable rate than Mysis relicta consuming Brine Shrimp nauplii, and can therefore be considered a more efficient food source. This study fails to reject the null hypothesis for the sample mean.

Implications:

.........This study may influence zoo personnel in their choice of food sources for native Mysis relicta populations. Because no significant difference in the mean propagation rates of the two Mysis relicta populations could be established it can be safely assumed that neither food source produces a greater number of Mysis relicta. However, the difference in variance in propagation rates was significantly greater in the Mysis relicta population consuming Brine Shrimp nauplii. This suggests that Rotifers are a more reliable, consistent food source. This factor, in conjunction with the stability of the food sources, their ease to maintain, and their cost to purchase and upkeep can be used to determine which food source is the most efficient for use at the Columbus Zoo and Aquarium. Throughout the year the Brine Shrimp nauplii population has been the most accessable and reliable food source for the Mysis relicta (the Rotifer population having crashed several times). The cost of Brine Shrimp is approximately $.26 an ounce and the cost of Rotifers is approximately $3.25 an ounce. Taking this into consideration neither offers a greater mean offspring to adult ratio and Rotifers produce a more reliable rate of propagation at a far higher price.