Population characteristics of a recovering walleye population, Sander vitreus, in Saginaw Bay, Lake Huron

Saginaw Bay, Lake Huron, supported a large walleye fishery, but the population crashed by the mid1940's. Walleye were scarce until the early 1980s, when a fingerling stocking program began, but natural reproduction was inadequate to sustain the population. Natural reproduction greatly increased beginning in 2003, and stocking was discontinued in 2006. We examined abundance, growth and diet of walleye as they recovered. Abundance increased, but growth began to decline, with large decrease by 2009. Declines in growth were associated with high densities combined with apparent prey limitations; walleyes consumed primarily emerald shiners, round goby, and invertebrates during spring and summer, but switched to age-0 percids during fall to the extent that yellow perch recruitment may be limited via high predatory demand. Clupeids were scarce in diets; paradoxically, low clupeid abundance favors walleye recruitment, but abundant clupeids previously promoted fast walleye growth. Maintaining both walleye and yellow perch will likely require rehabilitation of a traditional forage community that included now-extirpated species such as cisco.