Does Thiamine Deficiency Limit Lake Trout Natural Recruitment in Lake Champlain?
Lake trout restoration in Lake Champlain has been a priority management goal for decades following the species’ extirpation in the lake by the 1900s. Progress towards this goal has increased substantially since the late 2010s with consistent observations of lake trout natural recruitment. However, future natural recruitment may be at risk due to elevated offspring mortality associated with high alewife consumption leading to thiamine (vitamin B1) deficiencies, termed Thiamine Deficiency Complex (TDC), a frequent recruitment bottleneck for lake trout that have diets rich in alewife. This study will assess thiamine concentrations and diet patterns in both wild and stocked adult female lake trout collected from Lake Champlain across two years to inform fisheries managers about the severity of the deficiency in the lake trout population and the extent to which it may limit continued natural recruitment. Currently, thiamine concentrations for wild lake trout in Lake Champlain are unknown, yet recent research indicates that high alewife consumption may cause TDC to be a major impediment to restoration efforts. Thus, the study aims to provide a new perspective on the extent of TDC in Lake Champlain, which can be used to inform future lake trout monitoring and management.