expt_block  date        mussel_density  prey_eaten  carap_width  sex  parasite  
7           2012-07-24  2               1           14.9         M    No        
7           2012-07-24  4               0           14.2         M    No        
7           2012-07-24  6               1           12           M    No        
7           2012-07-24  8               3           11.1         M    No        
7           2012-07-24  10              6           10.6         F    No        
7           2012-07-24  16              2           11.6         M    No        
7           2012-07-24  24              5           13.9         M    No        
7           2012-07-24  32              5           11.2         M    No        
7           2012-07-24  2               1           12.5         M    Yes       
7           2012-07-24  4               0           11           F    Yes       
7           2012-07-24  6               3           12.6         M    Yes       
7           2012-07-24  8               1           9.8          F    Yes       
7           2012-07-24  10              1           12.7         F    Yes       
7           2012-07-24  16              4           11.7         M    Yes       
7           2012-07-24  24              1           11.6         F    Yes       
7           2012-07-24  32              0           11.9         F    Yes