Further Results from Spring and Fall Plantings of Legal-Sized, Hatchery-Reared Trout in Streams and Lakes of Michigan

Abstract

Further tagging experiments in Michigan with spring and fall plantings of brook trout (Salvelinus f. fontinalis, brown trout (Salmo trutta), and rainbow trout (Salmo gairdnerii irideus) from which recoveries were made during the 1942 trout season confirmed the conclusion that spring release of adult or near adult hatchery-reared brook trout and rainbow trout is more desirable than the fall planting of fish of a similar size. In some instances fall stocking of brown trout may furnish as good fishing in the following seasons as does spring planting. Recoveries of planted fish past the first season of availability ranged from 0.0 to 2.5 per cent in the second season and from 0.0 to 0.5 per cent in the third season. In either spring or fall planting of legal-sized fish, no advantage was gained by scattering the fish widely over the stream areas stocked. Eighty five per cent or more of the planted trout recovered were caught within 10 miles of the point of release, regardless of the season or method of planting. Brown trout moved the least and rainbow trout the most. About one-fourth of the brook trout tended to move 3 to 10 miles downstream, and the majority of the remainder were caught within 3 miles of the locality of release. More rainbow trout than any other species were recaptured 10 or more miles from the point of release. Fall plantings of adult brook trout in lakes were recovered at the rate of 56.7 per cent (range, 13.0 to 88.1 per cent). Unfortunately, a small percentage of the anglers removed an average of 89.4 per cent of the total catch during the opening weeks of the trout season. The average recovery from two spring plantings of brook trout in East Fish Lake in Michigan was 68.5 per cent. A brief review of the literature substantiates the conclusions reached as a result of the Michigan experiments. Differences in experimental procedure are pointed out, and some reasons are offered for the failure of fish planted in streams in the fall to survive the winter season.