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

Appendix J – Northern Pike Risk Assessment for Piscataquis River
Authors: Melissa Laser (editor), Fred Seavey (USFWS), Richard Dill (MDIFW), Merry Gallagher (MDIFW), Tim
Obrey (MDIFW), Jeff Reardon (Penobscot Trust), Rory Saunders (NOAA), Tara Trinko (NOAA)
Introduction
The Penobscot River is New England's second largest river, with a watershed that
covers about a third of the State of Maine (approximately 22,300 km 2 ; 8,600 mi 2 ). It
is 563 km long (350 miles) and has a total fall of 488 m (1,770 feet) from its highest
point, Penobscot Lake. There are diverse aquatic environments in the watershed
with over 2,575 km (1,600 miles) of streams and rivers and more than 625 lakes and
ponds with a total surface area of 103,036 ha (254,600 acres). For thousands of
years, diadromous fishes migrated through much of the basin, providing a
connection between the Gulf of Maine and inland terrestrial and aquatic ecosystems.
Since 1959, multiple reports have documented the issues facing diadromous fish
restoration in the Penobscot drainage.
In 2006, the Maine Departments of Inland Fisheries and Wildlife (MDIFW) and
Marine Resources (MDMR) began work on a strategic plan to restore diadromous
fish in support of the Penobscot River Restoration Project (PRRP). The overarching
goal of the Penobscot River diadromous fish restoration strategy is to restore and
guide the management of diadromous fish populations, aquatic resources and the
ecosystems on which they depend, for their intrinsic, ecological, economic,
recreational, scientific, and educational values for use by the public. At least 85
species of fish inhabit the Penobscot River basin (Baum 1983). Thirty-five are found
in marine or estuarine waters, 33 occur in freshwater, five species tolerate a range of
salinities, and 12 are diadromous species that migrate between marine and
freshwater habitats. All of the fishes are native to Maine with the exception of eight
freshwater species. Since 1983, black crappie, green sunfish, largemouth bass,
central mudminnow, white catfish, and northern pike have been illegally introduced
into the Penobscot basin. Brown trout, an exotic species native to Europe, is
currently stocked by MDIFW for recreational fishing in one body of water located
above a set of falls impassable to all species of fish but Atlantic salmon. Chain
pickerel and smallmouth bass, managed by MDIFW as sportfish, were introduced
into Maine waters in the 1800s and have been spread legally and illegally throughout
the basin. Landlocked salmon, rainbow smelt, lake trout and white perch are native
to the Penobscot basin, but their range has been artificially expanded. This
restoration strategy focuses on native diadromous fishes, which are all currently at
less than 1% of historic levels.
Northern pike is a non-native invasive species that has high potential for negative
ecological impacts on native species. Management objectives to contain or eradicate
this species within the Penobscot watershed may be in direct conflict with the
objectives of the diadromous fish restoration strategy. This conflict is most apparent
in actions relating to fish passage. The Howland by-pass, one aspect of the PRRP,
will allow diadromous species access to the Piscataquis drainage but also opens the
drainage to natural dispersal of northern pike.
PRFP Page 206