Deposition and Survival of Endemic Coregonid Eggs in Relation to Different Substrate Types in Bear Lake, Utah/Idaho

Bear Lake whitefish (Prosopium abyssicola) and Bonneville whitefish (P. spilonotus) are endemic to Bear Lake, Utah/Idaho and account for two of the six recognized species of the genus Prosopium. Although many important aspects of these fish have been investigated, little is known about key life history components such as spawning habitat preferences and the egg survival associated with spawning habitat selection. Four major substrate types were evaluated as to their suitability for spawning habitat (vegetation, rock, marl, and ancient gastropod shells) through a combination of in situ and laboratory experiments. Gill net catch results indicated where within the lake these fishes select as priority spawning locations. We used substrate baskets to assess resultant egg survival. Underwater video observations of these species provided further information on whitefish spawning preferences. In addition to gill net sampling, a controlled laboratory experiment was incorporated to investigate whitefish egg incubational time requirements. Results from this study provide vital information regarding spawning location, timing, and substrate preferences that can be used by managers to predict the survival of these endemic whitefish as various water storage and draw-down regimes are implemented.