Few studies have examined the movement of adult Pacific salmon Oncorhynchus spp. between the sea and rivers after they have entered a river. In this study, archival tags that recorded temperature and salinity were attached to pink salmon (Oncorhynchus gorbuscha) that had ascended one of four rivers in northern Japan, to examine their individual movement patterns among fresh, brackish, and salt water. Of 44 pink salmon tagged and released in the rivers, nine were recaptured in the same river where they had been tagged and released, four were recaptured in marine nearshore trap fisheries, and one was recaptured in a neighboring river from where it was tagged and released. Among the 14 recaptured tagged fish, abrupt changes in salinity records were found in seven tag records, indicating that tagged fish had returned to brackish or seawater. Six of the seven individuals were males, and the sex ratio was biased toward males when compared with all tag-released individuals. The results suggest that a substantial proportion of homing adult pink salmon may make short-term movements between fresh and saltwater during their spawning migration. Analysis of the tag-recorded water temperatures showed significantly cooler riverine temperatures compared with inferred temperatures of the coastal water (up to 20.5 °C). While many factors, including orienting behavior and male-biased dispersal, likely influenced the observed ‘probing’ behavior, I speculate that the temporal use of freshwaters rivers may be a thermoregulatory behavior to avoid high, stressful temperatures. Future research relating the short-term movements between fresh water and salt water to local environmental conditions is needed to investigate this hypothesis.

很少有研究检查成年太平洋鲑鱼Oncorhynchus spp的运动。进入河流后，在大海和河流之间。在这项研究中，记录温度和盐度的档案标签被贴在粉红鲑鱼（Oncorhynchus gorbuscha) 上升了日本北部四条河流之一，以检查它们在淡水、微咸水和咸水之间的个体运动模式。在河流中标记和释放的 44 条粉红鲑鱼中，有 9 条是在它们被标记和释放的同一条河流中重新捕获的，4 条是在海洋近岸诱捕渔业中重新捕获的，还有 1 条是在其被标记和释放的邻近河流中重新捕获的. 在重新捕获的 14 条标记鱼中，有 7 条标记记录发现盐度记录发生突变，表明标记鱼已返回咸水或海水。七个个体中有六个是男性，与所有释放标签的个体相比，性别比例偏向于男性。结果表明，很大一部分归巢的成年粉红鲑鱼在产卵洄游期间可能会在淡水和咸水之间进行短期移动。对标签记录的水温的分析表明，与推断的沿海水温（高达 20.5 °C）相比，河流温度明显更低。虽然许多因素，包括定向行为和偏向男性的扩散，可能影响了观察到的“探测”行为，但我推测淡水河流的临时使用可能是一种体温调节行为，以避免高温、压力大的温度。需要将淡水和咸水之间的短期流动与当地环境条件相关联的未来研究来调查这一假设。对标签记录的水温的分析表明，与推断的沿海水温（高达 20.5 °C）相比，河流温度明显更低。虽然许多因素，包括定向行为和偏向男性的扩散，可能影响了观察到的“探测”行为，但我推测淡水河流的临时使用可能是一种体温调节行为，以避免高温、压力大的温度。需要将淡水和咸水之间的短期流动与当地环境条件相关联的未来研究来调查这一假设。对标签记录的水温的分析表明，与推断的沿海水温（高达 20.5 °C）相比，河流温度明显更低。虽然许多因素，包括定向行为和偏向男性的扩散，可能影响了观察到的“探测”行为，但我推测淡水河流的临时使用可能是一种体温调节行为，以避免高温、压力大的温度。需要将淡水和咸水之间的短期流动与当地环境条件相关联的未来研究来调查这一假设。我推测淡水河流的临时使用可能是一种体温调节行为，以避免高温、压力大的温度。需要将淡水和咸水之间的短期流动与当地环境条件相关联的未来研究来调查这一假设。我推测淡水河流的临时使用可能是一种体温调节行为，以避免高温、压力大的温度。需要将淡水和咸水之间的短期流动与当地环境条件相关联的未来研究来调查这一假设。