Compass orientation of sockeye salmon fry from a complex river system

Abstract
Sockeye salmon (Oncorhynchus nerka) fry from the Weaver Creek – Harrison Lake population were tested to determine whether they exhibited directional orientation in the absence of water flow. The fry oriented in a generally north-northeast direction. The presence of the moon greatly enhanced the strength of the northward orientation response, and the moon may have provided the fry with guidance information. Tests with newly emerged fry indicated little or no response to a directionally altered magnetic field. Both the passage of time and exposure to Harrison River – Harrison Lake water enhanced the compass orientation response, implying that an inherited response is triggered by environmental and temporal cues.