Draft Study Plan Vol 1 (PDF) - Alaska Power and Telephone Company

DRAFT DOCUMENT
distinct seasonal changes in abundance in these areas have been noted, possibly
due to a shift in distribution to deeper offshore waters during winter (Barlow 1987, Dohl
et al. 1983).
The Alaskan stocks of harbor porpoises are distinct from the stocks present along
the Pacific coast of the continental U.S. The minimum population estimate for the
Alaskan stock is 24,635. 16 The fisheries for which the majority of incidental take
occurred were the salmon gillnet fisheries in Southeast Alaska, Copper and Bering River
district, Kodiak, and Alaska Peninsula. The estimated annual mortality rate incidental to
commercial fisheries is greater than 10% of the Potential Biological Removal (PBR) 17 ,
and, therefore, can not be considered insignificant. There are no reports of subsistence
take of harbor porpoise in Alaska.
Harbor porpoises are known to be present in Lynn Canal, though the Canal is not
considered critical habitat.
Impacts to Marine Mammals
Marine mammals would only be indirectly impacted if the Project has an impact
on salmon sustainability for the Chilkoot River watershed.
Botanical Resources
Most of the forests in the Haines area are in the sub-climax stage of ecological
succession and consist of old growth, uneven aged hemlock and spruce stands, with trees
averaging 100-150 feet in height and 2 to 3 feet in diameter. The project area was logged
in the 1990’s and now has a fair amount of deciduous second growth. In Figure 9 above
is the wetland delineation from the USF&WS website. Further wetland delineation will
be necessary that would include a rare plant survey.
Impacts to Botanical Resources
Impacts to vegetation by the Project can be minimized by utilizing the existing RS
2477 corridor on the west side of Chilkoot Lake, which is already established, although in
poor shape along certain segments. Similarly, following the existing RS 2477 corridor
above the lake will primarily only remove second growth of various deciduous species.
Old growth stands will be avoided, if practical. Floodplain vegetation will be the primary
class of vegetation removed with small areas of hemlock/spruce forest where necessary.
Their removal should not have a significant impact on the biological diversity of the
forest because of the Projects small footprint and because it was previously logged.
Threatened, Endangered, and Candidate Species
Below is a preliminary list of Endangered (E), Threatened (T), or Candidate (C)
species that may need to be addressed during investigations into project feasibility.
16 Source: www.nmfs.gov/tmcintryr/mammals/sa_rep/alaska/harbporp.html, November 18, 1997.
17 The PBR is defined as the product of the minimum population estimate (NMIN), one-half the maximum
theoretical net productivity rate, and a recovery factor: PBR=NMIN x 0.5RMAX x FR. The recovery
factor (FR) for this stock is 0.5, the value for cetacean stocks with unknown population status. Thus, for
the Alaska stock of harbor porpoise, PBR=(24,635 x 0.02 x 0.5), or 246 animals.
Draft Study Plan – June 2012 p. 28 Connelly Lake Hydroelectric Project