New York, August 24, 1917. No. 47 



Published to advance the Science of cold-blooded vertebrates 



DESTRUCTION OF LOG PERCH EGGS 

 BY SUCKERS. 



While collecting eggs of the log perch, Percina 

 caprodes, (Rafinesque), at Douglas Lake, Michigan, 

 during the second week of July, schools of suckers, 

 Catostomus commersoiui (Lacepede), were observed 

 raiding the spawning grounds of the log perch. These 

 suckers quietly entered the schools of log perch which 

 were spawning in the shallow water near shore, and 

 crowded the spawning fish aside to eat their recently 

 laid eggs. The suckers were shy and retired to deep 

 water when disturbed, returning again to the spawn- 

 ing grounds as soon as opportunity offered. They 

 were seen in and near the schools of log perch 

 throughout the day, for nearly two Weeks. 



Twenty of these suckers were captured about 

 9:30 A. M., while feeding among the log perch. Five 

 were killed at once. The remaining 15 were placed 

 in a live-car some distance from the spawning grounds 

 and killed at intervals during the next 24 hours. The 

 entire alimentary canal of each suckers was examined 

 immediately after each fish was killed, and the num- 

 ber of log perch eggs noted. The data are tabulated 

 below: 



