Ohio River Sauger Study
| Ohio River States Study Sauger Submitted by Doug Henley Kentucky Department of Fish and Wildlife #1 Game Farm Road Frankfort, KY 40601 doug.henley@mail.state.ky.us 502-858-1549 x362 The Ohio River stretches 981 miles from Pittsburgh, Pennsylvania to Cairo, Illinois and borders West Virginia, Ohio, Kentucky, Indiana, and Illinois before emptying into the Mississippi River. Once primarily important as a conduit of travel for people and goods, the Ohio River now serves outdoor enthusiasts as well. Anglers recognize the Ohio as a river of diverse fishing opportunities for all seasons. Fish and Wildlife departments up and down the river also recognize the value of these fishing opportunities. Administrators and biologists from West Virginia, Ohio, Kentucky, Indiana, and Illinois came together in 1990 to form the Ohio River Fish Management Team (ORFMT). Surveys indicated that sauger represented the second largest species group sought by anglers river-wide. However, fish numbers and sizes caught varied widely from year to year and from tailwater to tailwater. In fall of 1998, the Team decided to explore causes of these fluctuations and determine ways to optimize population levels throughout the river. Night electrofishing provided biologists with a valuable insight into sauger population dynamics. Sauger were the most abundant of two species in the electrofishing surveys. Walleye represented a small portion of the population and were most abundant in the upper pools. Most of the sauger sampled with electrofishing were less than 12.6 inches and were mostly young-of-the-year and 1-year-old fish. Sauger catch rates were lowest below New Cumberland Dam (17-34 fish/hour of electrofishing) and greatest in the Greenup tailwater (63-419 fish per hour). The fisheries were assessed using angler use or creel surveys. These surveys indicated that angler effort ranged between 6,972 and 26,152 hours of fishing at the different tailwaters. More than 50% of the anglers fishing during the winter were seeking sauger or walleye. Depending on the river conditions, it took anglers an average of 20 minutes to 1.5 hours to catch a sauger. Harvest ranged from 1,080 fish at New Cumberland tailwater to 8,463 at Markland tailwater. Size of sauger kept by anglers generally ranged between 12 and 16 inches. The creel indicated that over 37,000 sauger were caught and released at Greenup tailwater. Age and growth information indicated that sauger grew fast (15 inches by their third year of life), but very few survived beyond age 3. Something caused sauger to disappear at younger ages in the Ohio River. Fisheries managers use the term total annual mortality to describe all sources of fish mortality within a population. This may be further divided into fishing mortality (fish removed by anglers) and natural mortality (fish dying from “natural” causes). Total mortality rates for sauger between ages 1 and 2 in the Ohio River ranged between 63 and 98% and generally exceeded 90% in most tailwaters. Biologists were concerned that the truncated length and age structure and high mortality rates may be indicative of over-harvest. However, over-harvest cannot be confirmed until biologists determine the actual fishing and natural mortality rates. This study provided ORFMT biologists with an insight into sauger populations along the entire length of the Ohio River. Truncated size and age structure and high annual mortality of sauger in these tailwaters indicated the possibility of over-harvest by anglers. At this time, over-harvest cannot be confirmed until total annual mortality has been accurately divided into fishing and natural mortality. The next step by ORFMT biologists is to identify these specific sources of mortality and then we can begin exploring management options. |
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