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

Above1 Run 16.3 551 7 FLF, YLP,
WHS, CSK,
BND, CCB,
CMS
* MUS = Muskellunge, FLF = Fallfish, YLP= Yellow Perch, WHS = White Sucker, GLS = Golden
Shiner, CMS = Common Shiner, CSK = Burbot/Cusk, BND = Blacknose Dace, CCB = Creek Chub
Chain pickerel: A study conducted by MDIFW in the 1960s revealed that pickerel
were the most common predator on newly stocked salmon. Predation by pickerel
was observed at 27 of 42 lakes (64%) shortly after stocking of landlocked salmon
(Warner 1972). In all, 152 of 523 pickerel examined (30%) were found to have
recently consumed a newly stocked salmon. The average number of salmon per
pickerel was 1.9 fish; however one fish devoured 32 newly stocked salmon.
Barr (1962) reported significant predation on migrating sea-run Atlantic salmon
smolts by pickerel at Beddington Lake in the Narraguagus River drainage. In that
study, 21% of pickerel greater than 10 inches long were found to have consumed a
salmon smolt. Similarly, on the Penobscot River, Van den Ende (1993) documented
that Atlantic salmon smolts were the most important dietary item of chain pickerel
(11.5 - 24 inches in length) during the smolt run period on the Penobscot River,
where 58 percent of all pickerel stomachs contained food items and smolts
represented 80 percent of the wet weight of all prey items.
Pickerel predation on newly stocked brown trout was observed at Brandy Pond in
Hancock County in 1989. In that study, newly stocked spring yearling brown trout
were observed in the stomachs of 15 of 54 pickerel (28%). The smallest pickerel
that consumed a brown trout was 15 inches long. The mean length of the 54
pickerel examined was 16.9 inches. The experimental stocking was terminated due
to unsatisfactory survival.
Changes to Fish Communities after Introductions
Invasions or introductions of top predators into new ecosystems have been shown to
have negative effects on native top predators and dramatic cascading effects on
lower trophic levels (Vander Zanden et al. 2004). Several studies have attributed
large losses of stocked and migrating salmonids to pike predation in riverine
ecosystems. Petrvozvanskiy et al. (1988) documented that pike account for
approximately 35% of stocked Atlantic salmon smolt mortality in the Keret River in
Russia. Similarly, Larson (1985) and Kekäläinen (2008) attributed a 50% and 29%
loss respectively of migrating juvenile Baltic salmon to predation from pike. Jepsen
et al. (2006), working with hatchery stocked Atlantic salmon smolts and wild brown
trout observed 56% predation by pike during spring migration through Lake Tange, a
12 kilometer long reservoir in the Danish River Gudenå watershed. Rutz
(1996,1999) documented that juvenile salmon and trout species were the preferred
forage of pike in several southcentral Alaskan waters. Rutz reported that 80% of the
non-empty pike stomachs from the Susitna River contained salmonids, even though
suckers, sticklebacks, and other minnow species were present. He also notes that
many of Susitna drainage lakes and streams that once contained native populations
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