Operational Plan for the Restoration of Diadromous Fishes to the ...

Salmon catch/day
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Salmon catch/day Percent scarred
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Figure 1. Incidence of scars and trapnet catch rates of salmon on spawning
runs at Long Pond, Kennebec County, 1988-2000.
Northern Pike in Stony Brook: MDIFW Region B biologists surveyed Long Pond
tributaries in Mount Vernon for the first time on August 15, 2005. Long Pond is
actively stocked with fall yearling landlocked salmon and spring yearling brook trout.
Stony Brook and two proximate unnamed tributaries were surveyed to document fish
species composition and general fish habitat condition in 2005. Small sized (127-
229 mm length range) northern pike were documented in the two streams closest to
Long Pond, Stony Brook and an unnamed tributary to Long Pond. Water
temperatures at all sites were adequate for coldwater species management and are
likely used as thermal refuges by young pike and brook trout (Figure 2).
Stony Brook continues to be monitored and is frequently surveyed by backpack
electrofishing to assess fish community composition at various times of the year
(Table 2). The sample site is located downstream from the crossing with Belgrade
Road and the existing road-stream crossing culvert is impassable to upstream fish
movement. Northern pike have been collected at all survey events in June, July,
August and early September. Pike in Stony Brook typically range from 65 – 195 mm
and represent young of the year (YOY), or perhaps 1+ age fish. Three wild brook
trout (size range 142 – 164 mm) were collected during the April 2007 sampling event
only and are presumed to have dropped down from Stony Brook’s upper reaches.
Across all sampling events, water temperatures range from 11.0C (Sept 07) – 21.8C
(Aug 05) and appear to maintain adequate thermal regimes throughout summer for
coldwater species management.
The pattern of small sized pike present in Stony Brook during the summer months is
consistent with juvenile pike using the stream as a refuge. Stony Brook is a small
stream with an average width of 4.5m and does not provide adequate habitat or
water depth for larger sized pike. It is likely that Stony Brook acts as both a thermal
refuge and as a spatial refuge for small sized northern pike from Long Pond. Pike
PRFP Page 216
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% salmon with scars