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Nockamixon Lake

Trap Netting
June 19-21, 2007

From June 19 through 21 Pennsylvania Fish and Boat Commission (PFBC) biologists conducted a trap netting survey (6 nets) in the 1,450 acre Nockamixon Lake, Bucks County, in order to determine if channel catfish are reproducing enough to support the fishery without stocking. Seventy-seven channel catfish ranging in lengths from 5 to 29 inches were collected during the survey.

Channel catfish
Mike Hersch, fisheries biologist aide, holds a heavy 26 inch channel catfish

The catch rate of channel catfish was 0.56 fish per hour, meaning that 0.56 channel catfish were collected for every hour that the trap nets were fished. The southeastern Pennsylvania average catch rate for channel catfish in lakes is 0.26 fish per hour. Large channel catfish (> 20 inches) were collected at a rate of 0.13 fish per hour. The southeastern Pennsylvania average is 0.05 channel catfish per hour for this size group.

Catch rates indicated that channel catfish stockings have been successful, at the very least in initiating the building of a dense channel catfish population in Nockamixon Lake that supports a fairly popular directed fishery. Additionally, 12 channel catfish were collected (16% of the channel catfish catch) that were the result of spawning that had occurred between 2004 and 2006, years when no channel catfish fingerlings had been stocked in the lake. Their presence indicated that channel catfish stockings are not likely to be necessary to support the lake’s channel catfish fishery. As a result, future fingerling channel catfish stockings will not be recommended for Nockamixon Lake.

Naturally reproduced channel catfish
Naturally reproduced channel catfish from 2006 (left) and 2005 (right)

Other sportfish species of interest to anglers that were collected during the survey included white catfish up to 19 inches, black crappie up to 14 inches, chain pickerel up to 25 inches, and white perch up to 11 inches (Table 1). White catfish were captured at a rate of 0.25 fish/hour (S.E. Pa. avg. = .09/hr.), crappie at 0.46 fish/hour (S.E. Pa. avg. = 3.63/hr.), and white perch at 0.34 fish/hour (S.E. Pa. avg. = 19.4/hr.). The low number of chain pickerel (3) captured during the survey was due to their low vulnerability to being captured in trap nets during June. Additionally, thirty-three percent of the white perch collected exceeded 9 inches in length, which is noteworthy since there are few public lakes in southeast PA with white perch populations comprised of fish large enough to provide anglers with a high percentage of quality size fish. Forage fish were abundant, including alewife, gizzard shad, and small bluegill.

Nockamixon Lake is owned by the PA Department of Conservation and Natural Resources (DCNR) Bureau of State Parks as the centerpiece of Nockamixon State Park. The lake is located in Nockamixon State Park, which is along PA Rt. 563, just off of PA Rt. 313, five miles east of Quakertown and nine miles west of Doylestown in Bucks County.

Black crappie
14 inch black crappie

Chain pickerel
25 inch chain pickerel

White perch
Two 9 inch white perch

Table 1. Fish species collected from June 19 to 21 in trap nets at Nockamixon Lake.

Alewife 780* NM
American Eel 2 NM
Black Crappie 77 3 – 14
Bluegill 379* 2 – 7
Brown Bullhead 18 4 – 12
Chain Pickerel 3 23 – 25
Channel Catfish 77 5 – 29
Common Carp 34 NM
Gizzard Shad 1603* NM
Pumpkinseed 14 3-6
Walleye 1 20
White Catfish 37 8 – 19
White Crappie 2 5-7
White Perch 51 5 – 11
White Sucker 10 NM
Yellow Perch 2 5 – 11
* Estimated number caught
NM = Not measured


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