Hooking Mortality of Saugers in the Tennessee River
Sauger Stizostedion canadense fishing is an important seasonal activity in reservoirs on the Tennessee River. Anglers target saugers during the winter and early spring, when saugers migrate upstream in search of suitable spawning shoals. Although saugers can pass through the locks at some dams (Pegg et al. 1997; Maceina et al. 1996), passage rates are low and the dams serve to concentrate saugers for several months, where they are susceptible to high rates of exploitation (Pegg et al. 1996). Saugers remain concentrated in dam tailraces until the urge to find suitable spawning shoals results in rapid downstream dispersal, usually in late March or early April (Pegg et al. 1997 ). By late spring, saugers have dispersed into downstream reservoirs, where they are only incidentally caught for the remainder of the year.
In response to concerns that sauger populations were on the verge of collapse in several mainstem Tennessee River reservoirs in the early 1990s, the Tennessee Wildlife Resources Agency reduced the daily creel to 10 fish (walleyes S . vitreum and saugers combined) and imposed minimum size limits in 1992. The minimum size limit in Kentucky Reservoir, on the lower Tennessee River, was 356 mm total length; the size limit was set at 381 mm in all other waterbodies. It is commonly noted that a minimum size limit will be counter-productive if released fish suffer high mortality. Such was the concern of many Tennessee sauger anglers, who used techniques and terminal gear that routinely captured under-sized saugers which they had to release. Thus, we initiated this study of hooking mortality of saugers. Biologists were also concerned that the use of "stinger hooks" (a treble hook attached to the jig hook by a piece of monofilament) was increasing mortality because of foul-hooking.
Methods. We experimentally caught 113 saugers during this study; 74 fish were held in the net pen on four dates to assess overnight mortality, 19 fish were affixed with radio tags and released to resume a free-ranging existence, and the remainder (N = 20) only provided data on hook locations, bleeding, and gas bladder inflation overinflation. The mortality rate for saugers observed in the net pen was only 4% (3 of 74). Seventeen of 19 radio-tagged saugers were located and fifteen were alive 12 d later (12% mortality). Our findings of low hooking mortality for saugers in the Tennessee River agree with findings reported for walleyes in other waterbodies (Schaefer 1989). Although we could not detect a statistical relation between mortality and gas bladder overinflation, we did detect a weak (r2 = 14%) but significant (P = 0.002) relation between depth of capture and gas bladder overinflation as found in other fish species (e.g.,Keniry et al. 1996).When we caught saugers using the terminal gear most common in these fisheries (a bucktail jig tipped with a minnow and equipped with a trailing treble, or "stinger" hook), equal numbers of fish were caught by the jig hook and stinger hook. Despite the fact that 42% of all the saugers we caught were foul-hooked, bleeding from the primary hook wound only occurred in 20% of the fish we caught. Concerns that using a stinger hook increases rates of snagging and wounding are unfounded, because most (66%) saugers were "fairly" hooked (i.e., in the jaws or mouth) by the stinger hook, and the jig hook was responsible for twice as many foul-hookings as the stinger hook. We would expect that saugers retrieved rapidly from deep water (> 15 m) would suffer a higher incidence of gas bladder overinflation, and perhaps mortality, than fish brought to the surface slowly, similar to what Keniry et al. (1996) observed for yellow perch. Based on these findings, we recommend that the minimum size limit regulations remain in effect for saugers in Tennessee waters. We also conclude that prohibiting the use of stinger hooks based on biological or sociological considerations is unwarranted.
- Bettoli, P.W. 1998. Survey of the recreational fishery in Kentucky lake below Pickwick Dam, December 1997-April 1998. Fisheries Report 98-38, Tennessee Wildlife Resources Agency.
- Keniry, M.J., W.A. Brofka, W.H. Horns, and J.E. Marsden. 1996. Effects of decompression and puncturing the gas bladder on survival of tagged yellow perch. North American Journal of Fisheries Management 16:201-206.
- Maceina, M.J., P.W. Bettoli, S.D. Finley, and V.J. DiCenzo. 1996. Recruitment, movement, and exploitation of sauger in the Alabama portion of the Tennessee River. Alabama Department of Conservation and Natural Resources, Federal Aid in Sport Fish Restoration, Project F-40, Study 24, Montgomery.
- Pegg, M.A., J. B. Layzer, and P.W. Bettoli. 1996. Angler exploitation of anchor-tagged saugers in the lower Tennessee River. North American Journal of Fisheries Management 16:218-222.
- Pegg, M.A., P.W. Bettoli, and J. B. Layzer. 1997. Movements of saugers in the lower Tennessee River determined by radio-telemetry, and implications for management. North American Journal of Fisheries Management 17:763-768.
- Schaefer, W.F. 1989. Hooking mortality of walleyes in a northwestern Ontario lake. North American Journal of Fisheries Management 9:193-194.