RECOVERY OF A WILD BROWN TROUT STREAM
Tea Creek, a tributary to Kishacoquillas Creek at Reedsville in Mifflin County, maintained a Pennsylvania Fish and Boat Commission (PFBC) Class A wild brown trout fishery managed under conventional statewide angling regulations for fifteen years after cessation of hatchery stocking. Commission biologists reported wild brown trout biomass at 142.08 kg/ha for the August 1985 survey, 105.10 kg/ha for the August 1989 survey and 112.86 kg/ha for the August 1994 survey. PFBC minimum for wild brown trout management is 40 kg/ha.
Concrete poured into a sinkhole during construction on US 322 on August 5, 1997 caused a drastic chemical alteration resulting in a severe fish kill that largely destroyed the wild brown trout fishery of Tea Creek. Commission biologists reported that the August 1998 survey with a single pass conservative estimate of 28.02 kg/ha documented the early recovery of the fishery through reproduction by the few surviving adult brown trout and the high survival of fingerlings from that 1998 cohort.
Tea Creek was examined on August 7-8, 2000 to assess the condition of the wild brown trout fishery three years after the August 1997 pollution. The historical 360 meter electrofishing station was sampled using a Direct Current (DC) electrofishing generator.
Brown trout were captured in lengths from 2 to 13 in. Tea Creek has continued its recovery from the pollution of August 1997 to Class A status with an August 2000 biomass of 90.91 kg/ha well exceeding the Pennsylvania Fish and Boat Commission's minimum criteria of 40 kg/ha for wild brown trout management. Biomass for brown trout less than 150 mm total length was 15.87 kg/ha, exceeding the 0.1 kg/ha minimum.
Total brown trout biomass in August 2000 was 90.91 kg/ha, significantly higher than the conservative single pass estimate derived in August 1998 of 28.02 kg/ha only one year after the 1997 pollution and approaching pre-pollution biomass ranges of 105.10 kg/ha in 1989 to 142.08 kg/ha in 1985.
The 2000 survey of this small stream estimated 996 brown trout per mile in size groups from 2 to 13 in. with 24% of that total estimate exceeding the legal harvest length of 7 in. The 1998 survey estimated 812 brown trout per mile ranging in size groups from 2.0 to 10.8 in.; however, only 5.5% of that total brown trout estimate exceeded 7 in. The 1994 survey estimate of 726 brown trout per mile ranging in size groups from 2.0 to 15.7 in reported 43% of the total brown trout estimate exceeded 7 inches. The 1989 survey estimated 731 brown trout per mile ranging in size groups from 2.0 to 14.7 in. and reported 33% of the total brown trout estimate exceeded 7 inches. A mature wild brown trout population made up of more big trout very likely will have fewer trout per stream mile as seen in 1994 with a comparatively low 726 brown trout per mile, but recording a high 43% of that population at 7 inches and longer.
The August 1997 pollution and resulting fishkill severely damaged the reproducing brown trout population of Tea Creek. Fortunately, unlike with sedimentation or channel alteration, the stream habitat and spawning areas remained undamaged in the Tea Creek pollution. Increased reproduction and high survival of the 1998 and 1999 year classes combined with the excellent growth rates of a limestone stream and the reduced predation by a lower numbers of larger brown trout population following the fishkill have restored the reproducing brown trout fishery in Tea Creek to near historic wild brown trout abundance.
-- Area 7
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