Biotic and Abiotic Factors Influencing Cisco Recruitment Dynamics in Lake Superior during 1978–2007

Historically, the Cisco Coregonus artedi was abundant throughout the Great Lakes basin, but anthropogenic influences caused the collapse of stocks during the mid-1900s, and fishery managers are currently exploring options for restoration. To increase understanding of biotic and abiotic factors influencing Cisco recruitment dynamics throughout the Great Lakes, we used Ricker stock–recruitment models with rearing-habitat-weighted indices of recruitment and adult spawning stock size in Lake Superior to identify and quantify (1) the appropriate spatial scale for modeling age-1 recruitment dynamics and (2) the effects of biotic and abiotic factors on age-1 recruitment dynamics within the regions identified for modeling. Cisco recruitment variation in Lake Superior was best described by a regional model with separate stock–recruitment relationships for western, southern, eastern, and northern regions. The spatial scale for modeling was approximately 260 km. Age-1 recruitment was negatively correlated w...