An evaluation of harvest, survival, growth, and movement of five strains of rainbow trout (Salmo gairdneri) in Virginia Streams

Strains evaluated were Ennis (EN, domestic), Fish Lake (FL, wild), Mcconaughy (MC, wild), FGL Standard Winter (SW, domestic), and Sand Creek (SC, semiwild). In 1981, four Virginia put-and-take streams were stocked with 150 and 50 of each strain in March and May, respectively. Creel and electrofishing surveys were conducted to determine harvest, movement and survival after fishing. A reference (unfished) stream was also selected and stocked with 50 of each strain, and electrofishing surveys were conducted to determine survival, growth and movement. SW and EN strains were caught by anglers primarily during opening weekend (April 4-5, 1981), while the FL and SC strains were caught throughout the creel survey period. The MC strain was consistently lowest for total estimated harvest, while the SC and SW strains were equally high in total estimated harvest. Significant differences occurred in the proportional relationships of strain harvests among streams. May harvest results generally corroborated April results, except that significant differences among streams were not found. Greater survival for strains with low harvests during April was not evident in fished streams. Natural mortality rates in the reference stream did not differ significantly among strains between May 20 and October 22, 1981. Change in average length of the strains over four months in Spring Branch ranged from -4.3 mm for EN to +18.9 mm for SW. Percentage of stocked biomass of the SW strain remaining after five months (20.8%) in the reference stream was more than twice that remaining for the EN (9.6%) and SC (9.4%) strains. No significant differences in downstream movement, and no significant upstream movements, were observed for strains in the fished and reference streams.

Master of Science