Biologist reports logo Koon Lake

Bedford County
May 26, 2005

Located in Bedford County, Koon Lake is a 268-acre impoundment owned by the Evitts Creek Water Company and supplies water for Cumberland, Maryland. Koon Lake provides angling opportunities for largemouth bass and quality panfish. Koon Lake offers anglers the choice of fishing from shore (with the exception of the dam) or by boat that can be carried to the lake. Motorized boats used in the lake are authorized to use electric motors only. Anglers are fortunate that this water supply reservoir is open to public fishing; many water supply reservoirs in Pennsylvania are closed to angler use. The Koon Lake fisheries are managed under Statewide Conventional Inland Regulations.

Fisheries Biologist Aide, Charlie Weems with a largemouth bass from Koon Lake
Fisheries Biologist Aide, Charlie Weems with a largemouth bass from Koon Lake

Biologists from the PFBC, Fisheries Management Division conducted a night electrofishing survey in Koon Lake targeting the largemouth bass fishery. Scales were taken from all the largemouth bass caught in this survey to give the biologists insight into the age and growth of the largemouth bass. This information can then be used to make fisheries management decisions.

The mineralized dermal exoskeleton or scales taken from the largemouth bass are pressed into acetate (plastic) making an impression of the scale. The impression is then projected to ease the reading of the scale. When projected, rings can be seen on the fish scale similar to growth rings that can be seen on a tree. These rings called circuli are formed regularly but when growth slows in the winter these circuli become crowded or form incompletely. When growth resumes or accelerates in the spring the new circuli that form grow over or around the incomplete circuli forming the yearly growth ring known as the annuli (see the angler information sheet below titled This Fish Has a Scale to Tell - click on the graphic for the complete sheet). Results of this type of analysis has determined that it takes an average of 4 years for a largemouth bass in Koon Lake to reach 12 inches and an average of 6 years to reach 15 inches.

The largemouth bass collected in this survey ranged in size from the smallest that measured 3 inches in length and weighed ounce to the largest that was 22 inches in length and weighed 6 pounds 3 ounces. The total catch rate of 174 bass per hour of night electrofishing in 2005 was higher than any previous years sampling catch rates in Koon Lake. The catch rate for bass > 15 inches and > 12 inches was also the highest ever recorded during night electrofishing at Koon Lake. Although not the target of this survey a number of quality panfish were also observed.

Largemouth bass night electrofishing catch for Koon Lake

Size Group in Inches Sampling Year 2000 Sampling Year 2005
3 3 1
4 15 1
5 14 3
6 8 5
7 4 20
8 3 32
9 6 16
10 10 36
11 23 33
12 30 25
13 16 25
14 11 25
15   13
16   7
17 1  
18 1 1
20 1  
21 1  
22   1
Total 147 244
0.95 1.4
Catch per Hour 154.74 174.28
Catch per Hour
>= 12 Inches
64.21 69.28
Catch per Hour
>= 15 Inches
4.21 15.71

Bluegill (top) and pumpkinseed (bottom) from Koon Lake
Bluegill (top) and pumpkinseed (bottom) from Koon Lake

Average age and growth of largemouth bass in Koon Lake

Age Inches
1 4
2 7
3 9
4 11
5 13
6 14
7 16
8 18

This Fish Has a Scale to Tell - click for complete image/information

-- John Frederick, Area 7 Fisheries Technician

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