Shiawassee National Wildlife Refuge Manager Steve Kahl holds a young-of-the-year northern pike captured from the refuge during June. Photo by Anjanette Bowen, USFWS.

The Shiawassee National Wildlife Refuge (NWR) and Alpena National Fish and Wildlife Conservation Office (NFWCO), in cooperation with volunteers, conducted a northern pike (pike) survey on the Shiawassee NWR in Saginaw, Mich.  Pike is an interjurisdictional, native species that is dependent on wetland vegetation for spawning and nursery habitat.  Wetland habitat has been declining around the Great Lakes due to dredging, filling, draining and industrial use, to the detriment of pike.      

Due to the abundance of wetland habitat and the convergence of four rivers (Cass, Flint, Tittabawassee, Shiawassee), the Shiawassee NWR makes an ideal area to study pike.  Recently, a spillway was built on the refuge to replace a breach in the dike along the Cass River.  According to a survey we conducted prior to the dike restoration, the breached area provided pike access to the wetland above the dike during high water, and fish were using the area for spawning and as a nursery.   We were curious to know if the new spillway would continue to provide pike access to the wetland.    

Surveys were conducted in April, May, and June to document the presence of spawning and young-of-the-year pike at key locations on the refuge.  High water events were frequent this spring, and due to safety concerns and the ability to effectively sample, sampling was limited to four events from late March to early June. Trap nets were used to assess spawning northern pike (late March to late April), and a seine was used to assess young-of-the-year (April and early June).  Before returning pike to the water, we measured length and weight, took scales for aging, and noted the sex of the fish.