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Shenango River Lake
Mercer County
 
March 2010

Shenango River Lake is a US Army Corps of Engineers flood control reservoir located in southwestern Mercer County near the cities of Greenville, Mercer, Hermitage and Sharon. The reservoir covers 3,560 acres at normal summer pool; however, during our survey the lake was 2 feet below normal summer pool to facilitate flood storage. There are six boat launch ramps located around the reservoir. Most of the reservoir accommodates power boats of unlimited horsepower; however, some areas are designated for boats powered by 10 horsepower motors only and/or minimum wake operation only. The project maintains a large campground, Shenango Recreation Area. It provides hot showers, flush toilets, a sanitary disposal station and has a total of 330 campsites, many of which are equipped with electric hookups. For more information on recreational opportunities around Shenango River Lake visit the Army Corps of Engineers website at (http://corpslakes.usace.army.mil/visitors/projects.cfm?Id=H416700).

Black crappie
Tim Wilson and US Army COE Ranger Luke Houston with some nice black crappie from Shenango Lake

Shenango River Lake is stocked annually with muskellunge fingerlings, hybrid striped bass fingerlings and walleye fingerlings and fry by the Pennsylvania Fish and Boat Commission. The lakes black bass fishery is managed under Big Bass Regulations. All other species are managed under conventional statewide regulations.

Fisheries biologists Tim Wilson and Freeman Johns set trapnets during the week of March 22nd, 2010 to evaluate the status of the lake’s fish populations and the success of our stocking programs. Our sampling effort consisted of 16 overnight sets totaling 369.33 hours.

Our primary target was walleye, of which we captured only 25 (Table 1). Timing is everything in trapnetting for walleye and we were early. Most of the walleye we captured were green (not yet ripe) females. Even though water temperatures suggested they should have been spawning, walleye in Shenango River Lake were a week or more away from being ripe. Our fall 2009 assessment of the 2009 walleye year class produced a catch rate of 52.5 young-of-the-year walleye/hour, which suggests that fingerling and fry stocking are producing good results. Conversations with the local Waterways Conservation Officer and numerous anglers also suggest that there is a strong population of quality walleye in Shenango River Lake.

Another clue that we were too early for walleye was our catch of northern pike. Pike spawn before walleye and we hit the northern pike spawn dead center. We captured a total of 259 pike ranging from 12 to 38 inches. Many of the bigger pike were females running ripe with eggs. Most pike are captured by anglers targeting muskellunge.

Northern pike
US Army Corps of Engineers Ranger Luke Houston with a 35 inch northern pike

We were a little early for muskellunge and we only captured four (Table 1). Our next survey will be timed to target muskellunge to determine the success or failure of our stocking program. Over the years we have not been very successful in capturing muskellunge with trapnets in this lake, however, we do receive reports of anglers catching large muskellunge from Shenango River Lake.

Our other stocked species of interest was hybrid striped bass. We captured a total of 45, ranging from 9 to 28 inches (Table 1). This catch rate is similar to previous surveys and suggests that our stockings and regulations continue to maintain a quality fishery.

The lake was stocked with channel catfish between 1976 and 1995. These stockings developed into a naturally reproducing, self-sustaining and high density fish population. We captured a total of 298 channel catfish between 7 and 28 inches, which is excellent. In May of 2005 our trapnets captured 751 channel catfish, when the water was warmer and more conducive to catching channel catfish. Shenango River Lake provides an excellent opportunity for anglers to catch catfish from shore or boat.

Table 1. Length frequency distribution of larger gamefish captured in Shenango River Lake during the week of March 22, 2010.

Size Groups
(Inches)
Northern Pike Muskellunge Channel Catfish Walleye Hybrid Striped Bass Flathead Catfish
7     1      
8            
9     3 1 1  
10     9      
11     16      
12 1   10      
13     34   1  
14 2   20   1  
15 2   29 3 13  
16 1   35 2 11  
17 7   24 4 1  
18 9   29 2    
19 14   15 2 1  
20 16   22 2    
21 22   23 1 1  
22 29   17 2 1  
23 28   7 1 1  
24 29   1 1 1  
25 28   1 2 4  
26 18 1 1   2  
27 9 1 1 1 3  
28 11     1 2  
29 9          
30 3          
31 3          
32 2          
33 1 1        
34 3          
35 1          
36            
37 1 1        
38 2          
39            
40           1
1111 8       1  
Totals* 259 4 298 25 45 1
1111 – Fish that escaped before they could be measured
* - We also captured 221 silver redhorse, 385 quillbacks, 301 common carp along with spottail shiners, golden shiners, gizzard shad, white suckers, largemouth bass and smallmouth bass

White crappie
Fisheries Biologist Tim Wilson with a 15 inch and a 13 inch white crappie

Shenango Lake has a well deserved reputation for good crappie fishing. Our trapnet catches for both black and white crappie were excellent (See Table 2). Black crappie are the predominant species and outnumbered white crappie by about 10 to 1. Both species produced good numbers of quality size fish up to 15 inches. The crappie fishing should stay fairly consistent over the next few years because large numbers of young fish were captured as well.

Another nice development is the burgeoning white bass fishery. We captured 156 white bass with a nice size distribution (Table 2). White bass are classified as a panfish, therefore the creel limit is 50 and there is no size limit. However, to the untrained eye, they appear very similar to the hybrid striped bass that are stocked in the lake by the PFBC. Hybrid stripers are managed with a 20 inch minimum size limit and a creel limit of 2 per day, so it is very important that anglers learn to distinguish between the two.

Other panfish captured included bluegill, yellow perch and brown and yellow bullheads, none of which offered the quantity and quality of the crappie, but they still provide some recreational opportunities for anglers.

Table 2. Length frequency distribution of panfish captured in Shenango River Lake during the week of March 22, 2010.

Size Group (Inches) Black Crappie White Crappie White Bass Bluegill Yellow Perch Brown Bullhead Yellow Bullhead
2 5            
3 29 1   3      
4 1   15 8 2    
5 80   12 61 6    
6 48 3   120 19   2
7 363 15 3 70 8    
8 419 1 18   7    
9 163 10 25     2  
10 101 33 9     6 4
11 102 43 1     35  
12 54 9 23   1 19 1
13 6 7 16     1  
14 1 6 16        
15   1 15        
16     2        
17     1        
Totals 1,372 129 156 262 43 72 7

We returned to Shenango River Lake during the week of June 1st, 2010 to sample the bass population with night electrofishing. Over three nights and dodging numerous thunderstorms, we made 14 runs totaling 4.33 hours of effort. Shenango River Lake contains fishable populations of both largemouth and smallmouth bass. Comparisons of historic catch rates for largemouth bass, smallmouth bass and all bass combined are presented in the tables below.

Our total catch rate for 2010 for all bass combined was slightly above the long-term average for Shenango Lake at 56.3 bass per hour (Table 3 and Figure 1).

Table 3. Night electrofishing catch rates for All Bass Combined from Shenango River Lake.

Year 1990 1991 1992 1993 1994 1995 1996 1998 1999 2000 2003 2005 2006 2007 2010
Catch Per Hour 51.0 34.1 64.3 34.7 69.0 77.5 48.8 53.4 42.2 36.5 50.4 49.5 44.2 51.3 56.3
CPH SMB >12” 12.2 13.3 21.4 9.6 15.8 25.1 13.9 23.7 15.2 18.9 19.6 19.2 23.3 18.2 24.7
CPH SMB >15” 4.0 2.9 6.4 2.9 3.6 9.4 7.5 11.4 6.5 11.1 10.0 6.8 7.2 7.0 9.0

Figure 1

Similar to previous years, largemouth outnumbered smallmouth by about 2 to 1. Also similar to previous surveys, practically all the quality size bass were largemouth. The catch rate for largemouth bass over 12 inches was the highest ever and the catch rate for largemouth bass over 15 inches was the third highest ever.

Table 4. Night electrofishing catch rates for Largemouth Bass from Shenango River Lake.

Year 1990 1991 1992 1993 1994 1995 1996 1998 1999 2000 2003 2005 2006 2007 2010
Catch Per Hour 34.3 25.6 38.9 21.3 47.8 55.6 28.4 35.5 25.9 29.9 23.6 34.9 27.5 33.1 36.5
CPH LMB >12” 10.3 11.5 19.1 7.8 14.2 21.4 12.9 21.4 14.3 17.1 15.3 16.2 18.7 14.5 24.0
CPH LMB >15” 3.5 2.6 5.5 2.5 2.9 8.2 6.9 10.6 6.5 10.4 7.4 6.0 6.3 5.9 9.0

Bass
US Army Corps of Engineers Ranger Kyle Kraynak and Fisheries Biologist Aide Matt Gordon with some average bass from Shenango River Lake

Conversely, the catch rates for smallmouth bass over 12 inches and 15 inches were the lowest ever.

Table 5. Night electrofishing catch rates for Smallmouth Bass from Shenango River Lake.

Year 1990 1991 1992 1993 1994 1995 1996 1998 1999 2000 2003 2005 2006 2007 2010
Catch Per Hour 16.7 8.5 25.4 13.4 21.2 21.9 20.4 17.9 16.0 6.6 26.8 14.6 16.7 18.2 19.8
CPH SMB >12” 1.9 1.8 2.3 1.8 1.6 3.7 1.0 2.3 0.9 1.8 4.3 3.0 4.6 3.7 0.7
CPH SMB >15” 0.5 0.3 0.9 0.4 0.7 1.2 0.6 0.8 0.4 0.7 2.6 0.8 0.9 1.1 0.0
Despite the high number of largemouth bass over 12 inches, there was one disappointing note. No bass over 18 inches were captured this year, which hasn’t happened since 1994. Another new development, we observed perhaps thousands of juvenile yellow perch (3 – 6 inches) during our night electrofishing survey. We didn’t catch many yellow perch in our trapnets and they haven’t been a major component of Shenango River Lake’s fishery since the early 1990’s, but it appears that they are making a comeback. Lures shaped and colored like juvenile yellow perch might be very effective baits at Shenango right now.
 
— Area 1

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