Data was gathered experimentally at the Baruch Institute for Marine & Coastal Sciences. Ranking (day that mussel was consumed) was used to analyze size to size order of mussels consumed.
A broad size range of mussels was provided to the same 24 male crabs before and after claw removal to determine the impact of claw loss on prey size selection. Each crab was provided with 18 ribbed mussels (collected from North Inlet estuary)-3 from each of 6 different shell length size classes: 30-35 mm, 40-45 mm, 50-55 mm, 60-65 mm, 70-75 mm, and 80-85mm. The number ofmussels fromeach size class consumed on a daily basis was recorded over the 96-h experiment to determine which mussels were consumed first. The 1-clawed trials were conducted for an additional 24 h (120 h total) to compensate for lower overall feeding rates after claw removal.
The mean shell length of the ribbed mussels provided to the 1-clawed and 2-clawed crabs was 57.16 mm and 57.45 mm, respectively. The mussel shell length-to-crab CW size ratio (mussel-to-CW ratio) was calculated for each mussel to account for the range in crab sizes used in the experiment. The maximum mussel-to-CW ratio provided before and after claw removal was 1.21 and 1.20, respectively. The minimum mussel-to-CW ratio provided was 0.28 for both treatments. A multivariate linear mixed-effects model (Poisson distribution) was used to examine the order of mussel sizes cracked, with a higher ranking indicating they were consumed later. The number of claws, mussel-to-CW ratio, and crab size were included as predictor variables in this analysis, and crab identification number was used as the randomfactor to account for repeatedmeasurements.
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