Analysis of Carcinus maenas ingestion rates

Materials and methods
Part 1 - Control experiment
Two mussels (mytilus edulis) were opened and the mussels inside cut into 4 pieces, producing 8 pieces of roughly equal size in total. A balance was then tared with a weighing boat placed on it. Each piece of mussel flesh was placed individually and in turn into the weighing boat to be weighed. The pieces were then placed into a plastic bucket half filled with filtered seawater. The weight, time of weighing and time of immersion into the bucket were all noted down for each piece of mussel. The position of each piece of flesh inside the bucket was also taken down so as not to mix them up. One of the eight pieces was left in the bucket for the duration …show more content…
It shows that there is a positive correlation.

Figures 2 and 3 show that there is no significant relationship between meal size and crab wet weight OR time taken to eat the meal and the crab wet weight. p = 0.640, p = 0.550 respectively. The pearson correlation of SM_Size and SM_Time = 0.683, while the pearson correlation of SM_Time and WetWt = -0.131.
A chi-squared goodness of fit test was also performed during the analysis of the data, and showed statistically that rather than the 50:50 ratio of males to females that would be expected, there were far more males (Observed =32 males to 8 females, Expected = 20 males, 20 females).

Finally, analysis of the Eating rate (SM_size/SM_time) showed that the eating rates varied between the gender of the crabs.
The mean Eating Rate ( grams per minute) in females was 0.1965, while in males it was 0.4626. This shows that on average, the male crabs ate at a quicker rate.
Figure 4 shows this in a boxplot.The Q1 for Males is higher than the mean for females, which is a good indication that there is a noteworthy difference in means.

Control experiment results Figure 5 Percentage change in wet weight over