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" " . ,." e 10 e similar numbers of spawning chiselmouth chubs. Some hybridization may occur as fish were taken with appearances and meristic characteristics intermediate between the two spec~es. Male and fe~ile northern squawfish, were easily distinguished when in spawning condition. Males were darkly colored with dark lateral bands running the length of their sides. These bands were most obvious when seen underwater and on fish at spawning sites. On males not on spawning sites this dark lateral banding was not apparent. Many small tubercles on the bodies of males, especially on the tops of their heads often gave them a frosty appearance. Pectoral, pelvic and anal fins were dark yellow .to orange. Female fish were also darker than normal and many had bands on their sides but these features were generally duller than in males. Also loss pronounced than in males but pres,ent on females were tubercles and yellow fins. In contrast to males, the vents of females were enlarged, inflamed and protrusive. Most mature females were much larger than mature males (Table 1). In the St. Maries River for instance, ~ales averaged 282 rom while females averaged 375 mm Fl.. The probability is 95 percent that the actual difference between mature male and female lengths is included in the interval (70.5, US.s). Ages havE~ not as yet been determined from scales removed from spawning fish, however, some indication may be gained by comparison with age and length data collected by Reid (1971) from St. Joe River squawfish in 1969. Using this data, males in the St. Maries and St. Joe rivers apparently first mature at IV or V and females at VI or VII. The largest fish collected of each sex were at least age X and the average spawner age was VII for males and IX for females. Length-weight relationships and gonadal development patterns remain to be summarized and compared. ~