Steven Kahl/USFWS; 4/10/2008; Shiawassee National Wildlife Refuge; Deputy Refuge Manager Edward De Vries displays adult northern pike captured in refuge marsh.

Edward De Vries/USFWS; 4/09/2008; Shiawassee National Wildlife Refuge; Northern pike access refuge marshes when water flows over spillways.

Steven Kahl/USFWS; 6/03/2008; Shiawassee National Wildlife Refuge; Anjanette Bowen of the Alpena NF&WCO deploys a beach seine to catch young pike.

Steven Kahl/USFWS; 6/03/2008; Shiawassee National Wildlife Refuge; Young of the year northern pike from refuge marsh.

Shiawassee National Wildlife Refuge has partnered with the Alpena National Fish and Wildlife Conservation Office and refuge volunteers to assess the contribution of refuge wetlands to northern pike reproduction in the Saginaw Bay watershed.  Northern pike were once much more plentiful in the Saginaw River system.  Refuge visitors often speak of great pike abundance, especially during spring as pike swam up ditches to spawn in headwater wetlands.  However, pike numbers have declined due to loss of these wetlands in other areas of the watershed.

Refuge marshes provide spawning habitat for adult pike and nursery habitat for young-of-the-year and juvenile pike.  However, water levels in these marshes are primarily managed to provide habitat for migratory birds which the refuge was established to protect.  Additionally, refuge dikes and water control structures are thought to be a barrier to pike attempting to access impounded marshes.

This assessment is a follow up to work completed in 2000 in which pike use was measured in a marsh with no dikes adjacent to a river and a marsh surrounded by dikes.  Pike numbers were also measured in a third marsh with a breached dike.  In 2008, pike were netted in all three marshes, however, the breached dike was fixed in 2003.

Preliminary data reinforce that refuge marshes provide important habitat for spawning and young of the year pike.  Importantly, the marsh with no dikes yielded the most adult pike.  However, this assessment confirmed that pike do access impounded marshes during high water periods in early spring as water flows over spillways or as dikes are completely inundated.  In fact, a trap in a marsh surrounded by dike caught 23 adult pike in less than one day.