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Keystone Lake
Armstrong County
Spring 2008

Fisheries Management Area Two surveyed fish populations and evaluated the success of the walleye and tiger muskellunge stocking programs at Keystone Lake (also know as Keystone Power Dam) during the week of April 21, 2008. Keystone Lake is located in southeastern Armstrong County.

Keystone Lake covers 950 acres and its primary purpose is to supply water to the nearby power plant. The lake is fairly deep with steep banks, but there are several coves that provide shallow habitat. When the lake thermally stratifies in summer sufficient dissolved oxygen has been detected below the thermocline for coldwater species to survive. However, we have stocked many thousands of lake, brook, brown and rainbow trout fingerlings over the years with limited success in developing a desirable coldwater fishery. Our stocking efforts now are concentrated on tiger muskellunge fingerlings and walleye fry and fingerlings.

Rainbow smelt were stocked in the mid-1970’s as a forage species and now maintain themselves through natural reproduction. Emerald shiners were stocked in the early-1980’s and also sustain themselves through natural reproduction. These species along with juvenile sunfish, black and white crappies and yellow perch provide an abundant forage base for Keystone Lake’s predators.

We set trapnets for the entire week and set a few daytime gillnets on the 23rd and 24th. Weather for the entire week was beautiful and rising water temperatures had the fish moving throughout the lake.

We captured 9 tiger muskellunge ranging from 34 to 42 inches in length. The tigers in Keystone are quite healthy and heavy for their length. Keystone Lake has been managed exclusively for tiger muskellunge since 1999. Our survey catches have shown that we get better survival from the tiger musky fingerlings we stock versus the purebreds we stocked in the past. Tiger musky seem to survive and grow well in the deeper, coolwater lakes like Keystone Lake, East Branch Clarion River Lake in Elk County and Piney Reservoir in Clarion County, possibly because of their northern pike lineage.

Fisheries Biologist Tim Wilson with Keystone Lake tiger musky
Fisheries Biologist Tim Wilson with Keystone Lake tiger musky

We also captured 24 walleye between 18 and 29 inches in length. While this total is lower than we had hoped for, it is most likely due to the fact that the walleye had finished spawning and moved offshore, therefore, they were not as vulnerable to our nets, which were set in shallow water. All walleye captured were heavy for their length and were in excellent condition.

Fisheries Biologist Aide Jennifer Cessna with a 29.5 inch, 9.6 pound walleye
Fisheries Biologist Aide Jennifer Cessna with a 29.5 inch, 9.6 pound walleye

Our trapnet and gillnet catches revealed an outstanding black bass population in Keystone Lake. Generally, our Pennsylvania style trapnets are not effective in capturing bass (which is why bass are sampled by night electrofishing) but our trapnets and gillnets caught large numbers of bass, especially smallmouth. We captured a total of 108 smallmouth bass that ranged from 12 to 21.6 inches with 18 of them over 18 inches. We also captured 16 largemouth bass ranging from 8 to 18 inches. Keystone Lake’s bass have been managed under Big Bass Regulations since 1991.

A couple of nice smallmouths from Keystone
A couple of nice smallmouths from Keystone

Table 1. Size distribution of gamefish captured in Keystone Lake, Armstrong County during the week of April 21, 2008.

Size Group (in.) Tiger Muskellunge Walleye Smallmouth Bass Largemouth Bass Flathead Catfish

8       1  
10       2  
12     4 3  
13     5    
14     18 5  
15     22 2  
16     22 2  
17     19    
18   1 4 1  
19     10    
20   1 3    
21   2 1    
22   7      
23   2      
24   5      
26   1      
27   3      
28   1      
29   1      
34 1        
35 1       2
38 2        
39 1        
40 1        
41 1        
42 2        

Totals 9 24 108 16 2

The panfish population in Keystone is dominated by crappie and bluegills. Keystone Lake contains decent populations of both black and white crappie with black crappie outnumbering whites about three to two. While the total number captured wasn’t particularly high, the size of the crappie in Keystone Lake is nice with 61 percent of all black crappies and 69 percent of all white crappies over 10 inches (Table 2).

Some typical Keystone Lake crappies
Some typical Keystone Lake crappies

Bluegills were common in the shallow areas with only 18% greater than seven inches. Other panfish included a few yellow perch, pumpkinseeds, rock bass, green sunfish and brown bullhead.

Table 2. Size distribution of panfish captured in Keystone Lake, Armstrong County during the week of April 21, 2008.

Size Group (in.) Black Crappie White Crappie Bluegill Pumpkinseed Yellow Perch Green Sunfish Rock Bass Brown Bullhead

2     24          
3   1 14 1        
4 2   32 1        
5 2 1 36 5 2 1 1  
6 6 1 26 1 3 1    
7 17 17 21 2 3      
8 5 4 8 1 1   1  
9 16 2     1      
10 23 24     2      
11 26 13            
12 15 13            
13 9 3            
14 5 3            
15 1             1

Totals 82 127 161 11 12 2 2 1

We will return to Keystone Lake this fall to conduct night electrofishing for black bass.

-- Area 2

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