J.D. McIntyre — Page 2

USGS1977

Reassociation and hybridization properties of DNAs from several species of fish

Reassociation and hybridization properties from spectrophotometric studies of DNAs from 10 species of fish indicate: 1. Great diversity in the amounts of repeated sequences in the genomes of different species - more specialized fish had less redundancy. 2. Large differences in the complexities of the DNAs - more specialized fish had less information. 3. Little homology between sequences of remotely related species but substantial homology between sequences of closely related species.

Comparative Biochemistry and Physiology, Part B: C↗

USGS1977

Genetic differences in growth and survival of juvenile hatchery and wild steelhead trout, Salmo gairdneri

Relative growth and survival of offspring from matings of hatchery and wild Deschutes River (Oregon) summer steelhead trout, Salmo gairdneri , were measured to determine if hatchery fish differ genetically from wild fish in traits that can affect the stock–recruitment relationship of wild populations. Sections of four natural streams and a hatchery pond were each stocked with genetically marked (lactate dehydrogenase genotypes) eyed eggs or unfed swim-up fry from each of three matings: hatchery × hatchery (HH), hatchery × wild (HW), and wild × wild (WW). In streams, WW fish had the highest survival and HW fish the highest growth rates when significant differences were found; in the hatchery pond, HH fish had the highest survival and growth rates. The hatchery fish were genetically different from wild fish and when they interbreed with wild fish may reduce the number of smolts produced. Hatchery procedures can be modified to reduce the genetic differences between hatchery and wild fish.

Oregon↗