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

supplementation have been highly successful in re-establishing extirpated
populations of alewife and are currently used by many states.
Since the mid-1970s the State of Maine has successfully restored alewife runs to
more than 30 ponds in the Royal River, Androscoggin River, Kennebec River,
Presumpscot River, and the mid-coast region from Cape Elizabeth to Mt. Desert
Island by sequential, exogenous stock transfers (Damariscotta fish to the Royal,
Royal fish to the Androscoggin, Androscoggin fish to the Kennebec, Androscoggin
and Kennebec fish to the mid-coast). The exogenous alewives have flourished in
non-natal ponds that varied in size, depth, trophic status, resident fish community,
distance from the ocean, and elevation.
The best studied alewife restoration is in the Kennebec River watershed. The lack
of fish passage at the first dam (Edwards) for almost 150 years had caused the
extirpation of alewives from all upstream lakes and ponds. Restoration began in
1985 when DMR stocked 3567 alewives from the Androscoggin River into a single
lake above Edwards Dam. Stocking was expanded to six additional Kennebec lakes
as the Androscoggin run increased, and more adult broodstock became available.
Exogenous stocking from the Androscoggin was terminated in 1993, because the
number of alewife returns to Edwards Dam was sufficiently large to serve as
broodstock. Between 1993 and 1999, nine lakes above Edwards Dam and 14
additional in-basin and out-of-basin lakes were stocked with Kennebec alewife.
After the removal of Edwards Dam in 1999, returning alewives were able to migrate
17 additional miles upstream. Because alewives still had no access to spawning
habitat, DMR continued random stocking of adults into upstream lakes (i.e., adults
not necessarily trucked to natal waters). In 2006, DMR ceased stocking five of the
nine upstream lakes, because fish passage installation had made them accessible.
Interim passage at Fort Halifax (fish pump) did not allow all returning alewives to be
passed, so the total run size could not be determined. However, 500,000 to 600,000
fish were counted (combined passing and harvest) at Fort Halifax in multiple years
since 2002, and the run is estimated to be greater than a million fish.
Summary
Based on existing information, four stocks occur in the Penobscot River (above
Veazie, Silver Lake, Souadabscook Stream and Orland River). The ASMFS has
defined stocks for alewife as the river of origin, however the state typically manages
alewife based on the lake or pond of origin because of its life history. The
management definition of a stock lends support for homing of alewife to natal rivers.
Although not extensive, the literature available on stock identification based on either
meristic/morphology or genetic investigations indicates weak to moderate
differentiation that may (or may not) be based on geographic distance. The results
are consistent with homing to natal rivers but with a stray rate that appears to be
large enough to provide effective genetic interchange between populations (the
range of the FST values reported was 0.008 to 0.058 which would correspond with
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