Open Collections

Abstract

R. balteatus is extremely variable in number of anal rays. Counts of over 4000 specimens from 54 localities in British Columbia varied from 10 to 21, with differences between means of different populations, different year classes and sometimes between the sexes. Variation is shown to be controlled at least partially by environmental factors during development; temperature is an important factor. A mechanism for environmental control of fin ray count is suggested. Variation also occurs in body proportions. Inflections in relative growth of body parts is demonstrated; variation in proportions of these parts is probably due to environmental control of body size at Inflection. Pectoral and pelvic fins show heterogonic growth. Notes on life history are given. The spawning period varies from 7 to 10 weeks, starting between the last week of May end the second week of June. Individuals spawn at different times and probably more than once per season. Smaller fish frequent shallower water. Few fish are older than 4 years and females live longer than males. Relation of shiners to game species is discussed; shiners eat trout fry, trout eat shiners, and shiners probably sometimes compete with trout for other food.