BREEDING BEHAVIOR OF SUCKERS AND MINNOWS. IQ 



anals and caudal. With good lighting these could be seen with 

 the naked eye at a distance of ten or twelve feet. Subsequent 

 observation showed that all these fish were males. 



4. Breeding Activities. The fish were quiet most of the time, 

 but now and then one dropped downstream a few feet and then 

 slowly returned to his original position. Two of them were seen 

 to pick stones from the bottom as though feeding. After an hour 

 and a half a female joined the group of males. She was longer 

 and relatively thicker bodied than the males, not spotted with 

 white on the back and without visible pearl organs. She was at 

 once approached by five males, two of which took position one on 

 either side of her while the other three crowded down from above. 

 One of the upper males was seen to vibrate his tail for a moment 

 but no actual spawning took place at .the time. The fish re- 

 mained grouped for but an instant and then separated. The 

 female went upstream a little way and then dropped back 

 among the males. The group reformed, but immediately broke 

 up again. In these aborted attempts at spawning it was noted 

 that after a single male had placed himself by the side of a female 

 a second male, upon approaching on the same side, turned at 

 once to the unencumbered side. He behaved as though he 

 discriminated between the sexes of the two fish, but by what 

 means this was accomplished I could not tell. 



The female again went upstream but this time to a greater 

 distance and followed by two males only. When she had come 

 to rest on the bottom one of the males approached and placed 

 himself by her side. After half a second the other male took his 

 place on her opposite side and spawning occurred very much 

 as in the white sucker (Figs. 5, 6). The backs of the two males 

 were strongly arched so that their dorsal fins were carried well 

 above that of the female and fully spread. Their caudal and 

 anal fins were close pressed against those of the female and against 

 each other as in the w T hite sucker. Their snouts were turned 

 inward and pressed close against the sides of the head of the 

 female below her eyes (Figs. 5, 6). 



While the males were in this position with backs bowed and 

 heads straining inward and upward the female was held firmly 

 by the functional pearl organs of their snouts, caudals, anals 



