By Jordan Weeks

For musky anglers, it helps to know where in the lake, river, or reservoir muskies will be in order to maximize time and effort. After all, you can’t catch a musky where none exist, or at least exist at that period in time. Studies focusing on home rage, movement and habitat preference are quite common and can provide insight as to where muskies will be on any particular day. This fact holds true for musky fishing rookies and seasoned pros alike. Now, many longtime musky fishers have learned fish tendencies from logging time on the water, but anyone can speed up the learning curve by searching the scientific literature, DNR reports, and Fish and Game bulletins for studies done regarding muskellunge.

Take each study for what it’s worth … be sure to keep in mind the sample size (number of specimens studied ” more is always better), the length of time the study was performed (longer studies usually provide more accurate results), the location of the study (research done in Canada may not help someone fishing in Kentucky), and whether the study was published in a peer-reviewed scientific journal (these studies are considered “scientific fact” and are therefore better sources of information). To elaborate a bit on these points, a study with a sample size of seven fish studied (n=7) may show valuable tendencies but is not as significant as one with a sample size of 70 (n=70). This equates to “statistical power” and trends shown from 70 fish are much more valuable to scientists and anglers alike.  While working towards my master degree I came across two studies done on Iowa’s West Okoboji Lake that shed some light as to musky location from spring to fall. This information not only helped me design my research, but it helped me catch more muskies. Hopefully the review of these two articles will do the same for you.

Articles Summary
Both studies were done simultaneously by Marlyn L. Miller and Bruce W. Menzel, working for Iowa State University, and published in 1986. The study objectives were to use ultrasonic telemetry to determine movement, behavior, habitat use and activity patterns of nine tagged muskellunge from June 1978 to September 1979. Researchers contacted the nine study fish 1,292 times from spring 1978 to fall 1979. This data provides information as to the behavior of adult muskellunge in a large natural lake, and to relate the observed behaviors to environmental features.
West Okoboji Lake (3,805 acres) is a chain of recreationally-important natural lakes located in northwestern Iowa. This deep, productive, eutrophic lake has a large central channel bordered by several large, relatively shallow bays. Sand and gravel dominate the substrate in shallow areas while the main lake basin is dominated by muck bottom. Most of the shallow portion of the lake supports dense vegetation. West Okoboji stratifies in the summer, with a layer of well-oxygenated water in the upper 32 feet. Below 32 feet there is no useable oxygen for fish. Summer average water temperatures can exceed 77 degrees. Main forage fish include yellow perch, bluegills, pumpkinseeds, walleyes, northern pike, smallmouth bass, crappies, black bullhead, carp freshwater drum (sheephead), bigmouth buffalo, and golden shiners.

Muskellunge were captured via gill net in the spring spawning period. Six males and three females were tagged with temperature-sensing ultrasonic transmitters and released. From June 1 through August 31, 1978, fish movements were monitored daily. Some periodic 24-hour tracking efforts were also conducted, where individual fish were located every one to three hours. In 1979, daily observations began in late April through May. Weekly observations were made in June, July, and August.

Results
Researchers had an average of 10 contacts per fish per week during the study period. Of the nine fish with transmitters three fish were captured by anglers (33 percent), and one was released and two were kept (keep in mind this was 1978-79, when the catch and release ethic was just getting started). The study fish also showed spawning area fidelity, returning to the location of original capture in the spring of 1979.

After the tagged fish were released they dispersed throughout the lake. During early parts of the year fish abandoned shoreline littoral areas into open (pelagic) water and average weekly water depth increased accordingly. Depths ranged from 13 feet to 28 feet and study fish were often associated with schools of baitfish. By mid June when water temperatures had surpassed 63 degrees most fish had moved to bays where they established their summer home range. These home ranges were used by the same fish both years. Home range size varied among fish (96 to 1,094 acres) and averaged 360 acres. There was no significant difference in home range size between males and females or of any size fish. During the summer period, depth of water study fish were found in ranged from 15 to 19 feet. This depth range was associated with the outside weed edge in West Okoboji.

During the early summer pelagic period fish were active and movement rate typically exceeded 60 meters/hour. However, as fish moved from open water toward the weed edge, activity decreased. There was also a significant inverse relationship between fish activity and water temperature; as the water warmed above 63 degrees fish activity decreased. Fish activity was also linked to water transparency, and as water clarity decreased fish activity decreased.

All but one fish exhibited strong fidelity for vegetation during the summer months. At this time muskellunge were either suspended above the vegetation or between discrete vegetation patches. Three of the study fish were associated with vegetated reefs. When not associated with shoreline vegetation muskellunge tended to be suspended in the middle and upper portions o the water column, regardless of water depth. Throughout summer, fish occurring in deep water tended to be more active than when they were shallow. Significant diel differences in behavior occurred only during early summer when fish were occupying deep open water areas. During this time fish tended to be most active in late evening and early to mid-morning.

The Lowdown
So, what does all this mean? First, if you live where there is no closed season on muskellunge, search out shallow spawning bays. Once muskies are located continue to fish that location and let the fish come to you ” they will, year after year. For those of you fishing in places where the season is closed during the spawn, don’t despair. Some fish will always be shallow, hanging around emerging vegetation, when the season opens. However, if nothing is happening shallow, don’t be afraid to move out over open water, find some baitfish on the sonar and start slingin’. During this time fish activity is high, fish early to mid-morning and late in the evening.

Once the water warms and the thermocline forms (be sure to read Tom Gelb’s article, “Exploit The Summer Period,” Musky Hunter, June/July 2009), continue to hit the open water fish, as they should be the most active fish in the lake at this time. However, if you can’t bring yourself to fish over the “deep” remember as fish move into the weeds and visibility decreases musky activity also decreases. This means precision casting and slower presentations may produce. Fish every weed clump as if it holds a musky and hit every edge. Surgically dissect every piece of structure. Quality casting may outproduce quantity when fish are in the junk/slop.

These fish are in ambush mode, so use that information to get your lure in front of their face and make them eat it. This may be hard for many of us to do including myself ” I have been fishing fast for years trying to find the active fish. This research taught me that run and gun may not always be the best. In certain situations you need to slow down and pick apart the structure. Force feed the muskies.

References:
Miller, M. L. and B. W. Menzel. 1986. Movements, homing, and home range of Muskellunge, Esox masquinongy, in West Okoboji Lake, Iowa. Environmental Biology of Fishes 16(4):243–255.
Miller, M. L. and B. W. Menzel. 1986. Movement, activity, and habitat use patterns of muskellunge in West Okoboji Lake, Iowa. American Fisheries Society Special Publication 15:51–61.