Spawning migration and habitat selection by steelhead and longnose suckers in the Pere Marquette and St. Joseph Rivers, Michigan

I investigated the migratory behavior of steelhead (Oncorhynchus mykiss) and longnose suckers (Catostomus catostomus) in the Pere Marquette River using radio telemetry to provide base-line information prior to the construction of a proposed electrical sea lamprey (Petromyzon marinus) barrier. Steelhead arrived at the barrier vicinity on average within 8 days in 1997 and 18 days in 1998, and moved upstream quickly through the barrier vicinity, averaging 6 minutes (1997) and 32 minutes (1998). Longnose suckers arrived at the barrier on average within 17 days in 1998 and passed through the barrier vicinity within an average of 20 minutes. Steelhead and longnose sucker migrations corresponded with increasing water temperature and stream flows.; In addition to the Pere Marquette data, I used steelhead fishway passage data from the St. Joseph River, Michigan to develop a temperature-based movement rule to quantitatively predict the probability of upstream movement. Exponential, logistic and power functions were evaluated as a means to express the probability of movement. Of these, the power function provided the closest fit between observed and predicted movement. Stream flow was also evaluated as a means of expressing the probability of movement, but did not increase the predictive power of the model. Therefore, I used water temperature to predict upstream movements. The temperature-based movement model incorporates an increasing probability of movement for increasing water temperatures above the minimum temperature threshold for movement. By using data from two Lake Michigan tributaries, I was able to demonstrate that the modeling approach is transferable to other Great Lakes tributaries and that the model consistently demonstrates the upstream movement probability of steelhead in systems where upstream migration is governed by water temperature.; Finally, I evaluated features (groundwater presence, substrate particle size, etc…) associated with the selection of steelhead spawning habitat the Pere Marquette River. Steelhead redds were evaluated for the presence of groundwater using a GIS-based groundwater prediction model and another method based on intragravel temperature to provide insight to the importance of groundwater as a means of spawning habitat selection. The GIS model and probe-based evaluation were inconclusive as means to identify groundwater associated with steelhead redds. Steelhead preferred to construct redds in a substrate consisting of small gravel, large gravel, and small cobble particle sizes disproportionately to clay, silt, sand, and large cobble. Steelhead redds were located in areas where the stream velocity was significantly higher (F = 97.77, P < 0.0001) than velocities that were recorded at reference sites, and redds were located in water that was significantly shallower than what was typically found in the study reaches (F = 113.84, P < 0.0001). Stream temperature did not appear to influence the selection of redd locations.