expt_block  date        mussel_density  prey_eaten  carap_width  sex  parasite  
11          2012-07-26  2               0           11.8         M    No        
11          2012-07-26  4               2           10.7         F    No        
11          2012-07-26  6               5           13.8         M    No        
11          2012-07-26  8               0           10.8         F    No        
11          2012-07-26  10              0           9.7          M    No        
11          2012-07-26  16              13          11.5         F    No        
11          2012-07-26  24              10          11.7         F    No        
11          2012-07-26  32              10          13.6         M    No        
11          2012-07-26  2               0           10.6         F    Yes       
11          2012-07-26  4               0           12.3         F    Yes       
11          2012-07-26  6               2           10.2         M    Yes       
11          2012-07-26  8               0           11           F    Yes       
11          2012-07-26  10              2           10.8         F    Yes       
11          2012-07-26  16              3           10.2         F    Yes       
11          2012-07-26  24              1           11.3         M    Yes       
11          2012-07-26  32              0           11.8         F    Yes