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K.G. Whalen

Publications and source records attributed to K.G. Whalen.

3 recordsLinked to original sources
USGS2004

Winter growth and survival of juvenile Atlantic salmon (Salmo salar) in experimental raceways

We used experimental raceways to determine overwinter mortality of wild-reared immature and mature post-young-of-the-year Atlantic salmon (Salmo salar). Secondarily, we investigated the effects of differing treatments (velocity and shelter) on winter growth and survival. Overall survival from November to April was 94%, and survival of immature (98%) and mature (90%) parr, although statistically different, was very similar. Immature parr grew more in length than mature parr, and both immature and mature parr in higher velocity (12 cm??s-1) raceways grew more than those in lower velocity (0.6 cm??s-1) raceways. Stomach contents were twofold greater in parr occupying higher velocity raceways than those in lower velocity raceways. Caloric content of immature and mature parr did not differ in any of five monthly samples. Lowest caloric content occurred in early February and increased between February and March when water temperatures were well below those considered optimal for growth. Although ice cover was present, isolating parr from conditions that occur in natural settings may have helped parr achieve nearly 2.5 times greater survival than parr in the wild. Further, whereas previous studies showed parr select habitats to minimize energetic loss, our results show a distinct advantage for parr to expend energy to feed during winter. ?? 2004 NRC Canada.

Conference Paper↗
USGS1999

Migration timing of Atlantic salmon smolts relative to environmental and physiological factors

We determined the migration timing of fry‐stocked smolts of Atlantic salmon Salmo salar relative to environmental and physiological factors, by using net weirs and counting fences in three tributaries of the West River, Vermont. Smolt migration began in late April and early May when water temperature was 5°C, peak movements occurred in early and mid‐May at temperatures exceeding 8°C, and migration was complete by early June. Within this seasonal window, significant differences in migration timing and gill Na + ,K + ‐ATPase activity occurred among tributaries. In both years of the study, smolts tended to migrate earlier and exhibit greater gill Na + ,K + ‐ATPase activity in the warmest tributary than in the coolest tributary. Smolt migration timing differed most among tributaries in mid‐May when (1) water temperatures were more than 8°C, (2) smolts peaked in gill Na + ,K + ‐ATPase activity, and (3) discharge peaked, stimulating smolt migration. Smolts captured after the migratory period had lower gill Na + ,K + ‐ATPase activity than migrating smolts. Relating smolt physiology to migration was crucial for explaining complex interactions among water temperature, discharge, and smolt behavior during both the onset and cessation of migratory activity. Because the period between onset of migration and loss of smolt physiological characteristics may be brief, delays in downstream passage that may occur at dams must be minimized to maximize the successful recruitment of smolts to the marine environment.

Transactions of the American Fisheries Society↗