Adult striped bass Morone saxatilis (N = 30, 656–906 mm total length) were captured by electrofishing during January–March 1998 in the Combahee River, South Carolina, and fitted with radio transmitters. Their exact locations were recorded biweekly through December. From January to early April, striped bass were located in the tidally influenced lower region of the river in water temperatures ranging from 9°C to 18°C. The fish then moved an average of 38.5 km upstream from late April to the end of May when water temperatures ranged from 18°C to 26°C. Striped bass remained in the upper region of the river from late May to September when water temperatures were as much as 5°C lower than in the river's lower regions. Striped bass began to move downstream and were spread throughout the river during September and October in water temperatures ranging from 19°C to 27°C. Combahee River striped bass appear to follow a migratory pattern typical of other southern striped bass stocks. Habitat preference appears to be strongly influenced by temperature. Combahee River temperatures are stable and remain close to the preferred temperatures of striped bass during summer extremes. Therefore, unlike northern populations, southern populations are more likely to remain within riverine habitat during the summer months. Discrete thermal refugia, such as springs, apparently are not used or are absent in the Combahee River. It is possible that striped bass in the Combahee River depend on the entire upper region of the river as a thermal refuge.

The coastal rivers of South Carolina possess reproducing populations of striped bass Morone saxatilis. Historically, all of these populations have been augmented with hatchery stocks from the Santee–Cooper drainage. Concern has been expressed that locally adapted, reproductively isolated populations may exist in these coastal rivers. Thus, the objective of this effort was to assess the distinctiveness of reproducing striped bass populations in these coastal rivers. Tagging studies indicated that the interriver movement of striped bass was minimal. A population estimate of 406 striped bass longer than 30 cm was obtained for the Combahee River, suggesting a relatively small breeding population. Genetic assays at three nuclear restriction fragment length polymorphism sites showed highly significant allele frequency differences among seven coastal rivers, suggesting reproductive isolation. Partially or fully isolated populations can develop beneficial adaptations to local environmental conditions. Thus, we recommend the use of endemic stock to augment striped bass populations in the coastal rivers of South Carolina.