Incidental Takes of Marine Mammals During Specified Activities; Rat Population Eradication at Rat Island, AK, 51277-51290 [E8-20276]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 73, Number 170 (Tuesday, September 2, 2008)]
[Notices]
[Pages 51277-51290]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-20276]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XH04


Incidental Takes of Marine Mammals During Specified Activities; 
Rat Population Eradication at Rat Island, AK

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; issuance of an incidental take authorization.

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SUMMARY: In accordance with the Marine Mammal Protection Act (MMPA) 
regulations, NMFS has issued an Incidental Harassment Authorization 
(IHA) to the U.S. Fish and Wildlife Service (USFWS) for the take of 
marine mammals, by Level B harassment only, incidental to the 
eradication of non-native rat populations at Rat Island, AK.

DATES: The IHA is effective from September 1, 2008 through December 31, 
2008.

ADDRESSES: A copy of the IHA and the application are available by 
writing to Michael Payne, Chief, Permits, Conservation, and Education 
Division, Office of Protected Resources, National Marine Fisheries 
Service, 1315 East-West Highway, Silver Spring, MD 20910-3225, or by 
telephoning the contact listed here. A copy of the application 
containing a list of references used in this document may be obtained 
by writing to the address specified above, telephoning the contact 
listed below (see FOR FURTHER INFORMATION CONTACT), or online at: 
https://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in 
this notice may be viewed, by appointment, during regular business 
hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Howard Goldstein or Ken Hollingshead, 
NMFS, (301) 713-2289.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of marine mammals by U.S. 
citizens who engage in a specified activity (other than commercial 
fishing) within a specified geographical region if certain findings are 
made and either regulations are issued or, if the taking is limited to 
harassment, a notice of a proposed authorization is provided to the 
public for review.
    Authorization shall be granted if NMFS finds that the taking will 
have a negligible impact on the species or stock(s) and will not have 
an unmitigable adverse impact on the availability of the species or 
stock(s) for certain subsistence uses, and if the permissible methods 
of taking and requirements pertaining to the mitigation, monitoring and 
reporting of such takings are set forth. NMFS has defined ``negligible 
impact'' in 50 CFR 216.103 as ''...an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Except with respect to certain activities not pertinent here, the MMPA 
defines ``harassment'' as:
    any act of pursuit, torment, or annoyance which (I) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild [Level A harassment]; or (ii) has the potential to disturb a 
marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering 
[Level B harassment].
    Section 101(a)(5)(D) establishes a 45-day time limit for NMFS 
review of an application followed by a 30-day public notice and comment 
period on any proposed authorizations for the incidental harassment of 
marine mammals. Within 45 days of the close of the comment period, NMFS 
must either issue or deny issuance of the authorization.

Summary of Request

    On February 29, 2008, NMFS received a letter from the USFWS, 
requesting an IHA. The proposed 2008 IHA was published, and comments 
solicited on June 18, 2008 (73 FR 34705). The final IHA would authorize 
the take, by harassment only, of small numbers of Steller sea lions 
(Eumetopias jubatus), and Pacific harbor seals (Phoca vitulina 
richardsi), incidental to non-native rat

[[Page 51278]]

population eradication via bait application operations. Operations will 
be conducted by a field crew of USFWS personnel on foot, by watercraft 
(boat), and by aircraft (helicopter).
    Additional information on the eradication operations is contained 
in the application and Environmental Assessment (EA), which is 
available upon request (see ADDRESSES).
    In their application, the USFWS explains that restoration of 
natural ecosystem function on Rat Island promises to re-establish 
native seabirds and other native species, thus returning this 
wilderness island to a healthy natural community. This restoration 
cannot occur until the island is cleared of the invasive non-native 
Norway rats that now dominate the living community. Introduced non-
native species are a leading cause of extinctions in island communities 
worldwide. Increasingly, land managers are removing introduced species 
to aid in the restoration of native ecosystems. Rats are responsible 
for 40-60 percent of all recorded bird and reptile extinctions 
worldwide. Given their widespread successful colonization on islands 
and the resulting impact to native species, introduced rats are 
identified as key species for eradication.
    Most of the Aleutian Islands lying within the Alaska Maritime 
National Wildlife Refuge (AMNWR) provide important breeding habitat for 
seabirds, including many for which the Aleutians provide a substantial 
portion of their worldwide range. Norway rats are established on at 
least 10 Aleutian islands or island groups, and the diversity and 
numbers of breeding seabirds occurring on those islands are now 
conspicuously low. Rat-caused modifications to other components of the 
island ecosystems (e.g., other birds, plants, and invertebrates) are 
also evident.
    The restoration of Aleutian ecosystems through introduced predator 
eradications has long been identified as a priority for AMNWR, and the 
initial efforts have been directed to removing introduced Arctic foxes. 
The focus now has turned to rats. The intent of the proposed operations 
is to facilitate the restoration of the natural island ecosystem by 
improving habitat quality for native species.

Dates, Duration, and Region of Activities

    Rat Island is located in the western Aleutian Islands approximately 
51[deg] 80' North, 178[deg] 30' West, approximately 1,931 km (1,200 mi) 
west of Anchorage, Alaska. The Ayugadak Point rookery is located on an 
islet approximately one mile southeast of Rat Island at 51[deg] 45.5' 
North, 178[deg] 24.5' East.
    The location and time duration of the project activities are shown 
in the table below. Also shown are the estimated numbers of marine 
mammals affected by each activity. The timeline for the Rat Island rat 
eradication operations is shown in Table 1. Actual dates of activity 
occurrence are subject to weather conditions suitable for safe and 
effective flying of helicopters. While 5 days (approximately 35 
helicopter flight hours) will be required to complete the two aerial 
bait applications on the island, the operation is likely to be 
interrupted by weather unsuitable for flying. Therefore, a maximum of 
45 days will be allotted to achieve the 5 day operations window. The 
dates for bait application and demobilization will be weather 
dependent.

                                       Table 1. Timeline for the rat population eradication at Rat Island, AMNWR.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                             Location                                                    Rat Island                           Islet near Ayugadak Pt.
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                         Project activity                              staging        bait application    demobilization         bait application
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Time duration                                    2 days               5 days           2 days                      15 minutes
                       Type of disturbance                             helicopter           helicopter       helicopter                      helicopter
        of takes (Steller sea lions/ harbor seals)                  0/25              130/200             0/25                           320/0
--------------------------------------------------------------------------------------------------------------------------------------------------------

Description of the Specified Activity (Rat Eradication)

    Rats were first introduced to Alaska over 200 years ago at Rat 
Island in the western Aleutian Island archipelago. Prior to this 
introduction, the island likely supported significant populations of 
breeding seabirds and other ground nesting birds which evolved in the 
absence of mammalian predators. Since their introduction, rats and 
foxes have extirpated breeding seabirds and had detrimental impacts on 
vegetation and intertidal life on the island. AMNWR personnel 
eradicated foxes on Rat Island in 1984. Working with others, the USFWS 
proposes to eradicate rats from the island using removal techniques 
based on successful island rat eradications elsewhere in the U.S. and 
globally.
    The purpose of eradicating rats from Rat Island is to conserve, 
protect and enhance habitat for native wildlife species, especially 
nesting habitat for seabirds, and to restore the biotic integrity of 
the island. The overarching goal in a successful eradication is to 
ensure the delivery of a lethal dose of toxicant to every rodent on the 
island. The primary method for eradicating rats from Rat Island is 
delivery of compressed-grain bait pellets containing rodenticide to 
every rat territory on the island through aerial broadcast. The bait 
pellets will contain 25 ppm brodifacoum and will be applied according 
to Environmental Protection Agency (EPA) approved label directions.
    The need for caution near the marine and freshwater environments 
requires a buffer when broadcasting the rodenticide. As a result, some 
areas may not receive the optimal bait coverage with helicopter 
broadcast. In cases where it is evident or suspected that any land area 
on Rat Island or offshore islets did not receive full coverage, there 
will be supplemental systematic hand broadcast either by foot, boat, 
helicopter, or any combination of the above. All bait application 
activities will be conducted by, or under the supervision of, a 
Pesticide Applicator certified by the State of Alaska.

Staging and Preparation for Rat Eradication Operations

    Field crews will visit Rat Island in the end of summer or beginning 
of autumn prior to the rat eradication to install temporary 
infrastructure and storage sites. These will include: (1) a camp site 
capable of supporting 20 people for up to seven weeks; (2) three bait 
staging areas, where bait will be contained in up to 200 storage units 
at each staging area; and (3) a fuel storage site that will comply with 
all appropriate safety standards and regulations.
    Additional material may be brought to the island at that time and 
staged for the fall application of bait. Helicopters will deliver most 
of the necessary materials to each site on the island from a vessel 
anchored nearby. Staging procedures in summer will be conducted using a 
helicopter capable of lifting a 700 kg (1,543 lbs) payload. Helicopter

[[Page 51279]]

operations during project staging will be localized to discrete flight 
paths and landing sites servicing the camp, three bait staging 
locations, and a fuel storage site.
    It is possible that some of the material needed for eradication 
will not be available in the summer. In this case, that material will 
be staged on the island during the week prior to the fall application 
of bait.

Staging and Preparation at Rat Island

    The summer staging and preparation activities for Rat Island are 
expected to take 5 days during September. Dates for activities at Rat 
Island are subject to change due to scheduling and logistics concerns. 
Helicopter support during this period is estimated to take two days. 
Wooden storage boxes and platform construction materials will be staged 
at three areas, as indicated in Figure 1 in USFWS' IHA application. 
Fuel and all other camp materials will be delivered to the Gunner's 
Cove field camp location. The R/V Tiglax will be providing vessel 
support for the activities.
    A field camp will be installed at a site 600 m (1,968 ft) inland to 
Gunner's Cove. A loading zone for the staging of bait and fuel storage 
will be placed inland 500 m (1,640 ft) from the coast. The field camp 
will be 800 m (2,624 ft) from the loading zone and 600 m from the beach 
site. The anchorage in Gunner's Cove is 800m from the loading zone and 
700 m (2,296 ft) from the beach site. The helicopter will transport 
cargo from ship to shore at each of the three major project zones 
(field camp, loading zone, and Gunner's Cove beach site).
    All materials not available during the summer staging and 
preparation periods will be transported to Rat Island during the week 
of September 22-27, 2008. Helicopter support during this period is 
estimated to take two days.

Demobilization

    Once eradication has been completed operational demobilization and 
clean-up will commence. A charter vessel will be employed to transport 
all crew and equipment off the island. Demobilization and clean-up will 
include deconstructing and removing: (1) field camp; (2) garbage and 
human waste; (3) staging areas; and (4) fuel. All tents, weatherports, 
and other field camp equipment will be disassembled, packed, and 
returned to the vessel by helicopter. All equipment will be removed 
from bait staging areas and transported off the island. The wooden 
storage boxes will be disassembled, bound, and transported by 
helicopter back to the vessel. Excess fuel will also be transported 
back to the vessel by helicopter. There will be no demobilization at 
the islet near Ayugadak Point.
    Additional details regarding the rat eradication operations can be 
found in the Environmental Assessment (EA): ``Restoring Wildlife 
Habitat on Rat Island'', USFWS 2007 (EA). The EA can also be found 
online at: https://alaskamaritime.fws.gov/news.htm

Demobilization at Rat Island

    Demobilization and clean-up activities will commence once the 
eradication operations are complete. The demobilization is estimated to 
take five days and is scheduled for the week of November 1-7. If 
favorable weather conditions allow the eradication operation to be 
completed prior to October 31st, demobilization could begin during the 
month of October.

Bait Application During Specified Activities

    Bait application operations will be conducted using two single-
primary-rotor/single tail-rotor helicopters. Bait will be applied from 
specialized bait hoppers slung 15-20 m (49-66 ft) beneath the 
helicopter. Helicopter operations for the bait application will 
necessitate low-altitude overflights of the entire land area of Rat 
Island and adjacent vegetated islets. The helicopter will fly at a 
speed ranging from 25-50 knots (46-93 km/hr or 29-58 mph) at an average 
altitude of approximately 50 m (164 ft) above the ground.
    To make bait available to all possible rat home ranges on the 
island, bait will need to be applied evenly across emergent land area, 
with every reasonable effort made to prevent bait spread into the 
marine environment. The baiting regime will follow common practice in 
which parallel, overlapping flight swaths are flown across the interior 
island area and overlapping swaths with a deflector attached to the 
hopper (to prevent bait spread into the marine environment) flown 
around the coastal perimeter. Flight swaths will be defined by the 
uniform distance of bait broadcast from the hopper, ranging from 50-75 
m (164-246 ft). Flight swaths will be flown in a parallel pattern, with 
subsequent flight swaths overlapping the previous by approximately 25-
50% to ensure no gaps in bait coverage.

Bait Application at Rat Island

    Bait application will commence once staging and preparation have 
been accomplished as planned. The application will occur during a 45-
day time period from September 28-November 11, 2008. The bait 
application is estimated to take approximately 35 hours total flight 
time; however, the implementation will likely be interrupted by typical 
fall weather patterns in the central Aleutians, which are notoriously 
unsettled. Therefore, a maximum of 45 days will be allotted to achieve 
the 35 hour operation window.

Bait Application of the Rookery on the Islet off Ayugadak Point

    The islet located 1.6 km (1 mi) off Ayugadak Point is a Steller sea 
lion rookery, designated as Critical Habitat under the Endangered 
Species Act (ESA). The islet is also potential rat habitat and the 
thick kelp beds between the main island and this islet make rat 
migration to and from the islet possible. Bait, via the installation of 
bait stations, was planned to be delivered to the islet off Ayugadak 
Point with an adaptive alternative-baiting strategy designed to 
minimize helicopter disturbance. Due to timing constraints, USFWS was 
not able to install the bait stations as originally planned in the 
proposed IHA application. During fall operations, project field crews 
will treat the islet as necessary by aerial broadcast in October. This 
would take place during the October1-November 11 time frame and require 
approximately 15 minutes of helicopter flight time. No other equipment 
will be used that requires demobilization at the islet.

Description of Marine Mammals in Activity Area

    The marine mammals that occur in the project area belong to four 
taxonomic groups: odontocetes (toothed cetaceans, such as dolphins and 
sperm whale), mysticetes (baleen whales), pinnipeds (seals, sea lions, 
and walrus), and fissipeds (sea otter). Of the 18 cetacean species in 
the area, several are common.
    Six cetacean species are listed as endangered under the ESA, 
including the humpback, sei, fin, blue, North Pacific right, and sperm 
whales. Other cetacean species that potentially could occur in the 
western Aleutian islands includes Cuvier's, Baird's, and Stejneger's 
beaked whales, beluga, killer, and short-finned pilot whales, Pacific 
white-sided and Risso's dolphin, and harbor and Dall's porpoises. 
Because the proposed activity will occur predominantly over land, 
however, and because of the low probability of cetaceans occurring in 
the immediate vicinity of the island shore and the fact that USFWS will 
follow established procedures to ensure that bait is not released into 
the marine environment, NMFS believes it is unlikely that any

[[Page 51280]]

cetaceans will be harassed by the proposed activity. Therefore, 
cetaceans will not be addressed further.
    Four species of pinnipeds potentially could occur in the western 
Aleutian Islands, including Steller sea lions, Pacific harbor seals, 
northern fur seals, and ribbon seals. Numbers of Steller sea lions, 
harbor seals, and northern fur seals have been decreasing in the North 
Pacific over the last several decades (Springer et al., 2003). Although 
causes of the declines are poorly understood, it is evident that 
incidental mortality attributable to commercial fisheries and 
intentional harvesting during the 1960s and 1970s have played a role in 
the initial declines, and that predation by killer whales is a 
contributing factor (Springer et al., 2003).
    The Pacific walrus, California sea lion, and ringed, spotted, 
bearded, and northern elephant seals likely will not be encountered in 
the study area, but they are known to occur in the eastern Aleutians. 
The northern sea otter (Enhydra lutris) and walrus are managed by the 
USFWS. Walrus are unlikely to be encountered in the study area and any 
potential take of sea otters will either by authorized by the USFWS or 
avoided. Few surveys have examined the distribution and abundance of 
marine mammals inhabiting the waters around the Aleutian Islands, 
although a few reports are available (e.g., Forney and Brownell, 1996; 
Moore, 2001; Wade et al., 2003).

     Table 2. The habitat, and conservation status of marine mammals
       inhabiting the proposed study area in the Aleutian Islands.
------------------------------------------------------------------------
             Species                       Habitat             ESA\1\
------------------------------------------------------------------------
Mysticetes
----------------------------------
North Pacific right whale          Coastal and shelf        EN
 (Eubalaena japonica)
------------------------------------------------------------------------
Gray whale (Eschrichtius           Coastal, lagoons         NL
 robustus)
------------------------------------------------------------------------
Humpback whale (Megaptera          Mainly nearshore waters  EN
 novaeangliae)                      and banks
------------------------------------------------------------------------
Minke whale (Balaenoptera          Shelf, coastal           NL
 acutorostrata)
------------------------------------------------------------------------
Blue whale (Balaenoptera           Pelagic and coastal      EN
 musculus)
------------------------------------------------------------------------
Sei whale (Balaenoptera borealis)  Primarily offshore,      EN
                                    pelagic
------------------------------------------------------------------------
Fin whale (Balaenoptera physalus)  Slop, mostly pelagic     EN
------------------------------------------------------------------------
Odontocetes
----------------------------------
Sperm whale (Physeter              Pelagic, deep seas       EN
 macrocephalus)
------------------------------------------------------------------------
Cuvier's beaked whale (Ziphius     Pelagic                  NL
 cavirostris)
------------------------------------------------------------------------
Baird's beaked whale (Berardius    Pelagic                  NL
 bairdii)
------------------------------------------------------------------------
Stejneger's beaked whale           Likely pelagic           NL
 (Mesoplodon stejnegeri)
------------------------------------------------------------------------
Beluga whale (Delphinapterus       Coastal, ice edges       NL
 leucas)
------------------------------------------------------------------------
Pacific white-sided dolphin        Offshore, inshore        NL
 (Lagenorhynchus obliquidens)
------------------------------------------------------------------------
Risso's dolphin (Grampus griseus)  Offshore, inshore,       NL
                                    >400m
------------------------------------------------------------------------
Killer whale (Orcinus orca)        Widely distributed       NL
------------------------------------------------------------------------
Short-finned pilot whale           Inshore and offshore     NL
 (Globicephala macrorhynchus)
------------------------------------------------------------------------
Harbor porpoise (Phocoena          Coastal, inland waters   NL
 phocoena)
------------------------------------------------------------------------
Dall's porpoise (Phocoenoides      Slope, offshore waters   NL
 dalli)
------------------------------------------------------------------------
Pinnipeds
----------------------------------
Northern fur seal (Callorhinus     Pelagic, breeds          NL
 ursinus)                           coastally
------------------------------------------------------------------------
California sea lion (Zalophus      Widely distributed       NL
 californianus)
------------------------------------------------------------------------
Steller sea lion (Eumetopias       Mostly pelagic, high-    NL
 jubatus)                           relief
------------------------------------------------------------------------
Pacific Walrus (Odobenus rosmarus  Ice                      NL
 divergens)
------------------------------------------------------------------------
Bearded seal (Erignathus           Ice                      NL
 barbatus)
------------------------------------------------------------------------
Pacific harbor seal (Phoca         Coastal                  NL
 vitulina richardsi)
------------------------------------------------------------------------
Spotted seal (Phoca largha)        Ice                      NL
------------------------------------------------------------------------

[[Page 51281]]

 
Ringed seal (Pusa hispida)         Ice                      NL
------------------------------------------------------------------------
Ribbon seal (Histriophoca          Ice                      NL
 fasciata)
------------------------------------------------------------------------
Northern elephant seal (Mirounga   Coastal, pelagic when    NL
 angustirorostris)                  migrating
------------------------------------------------------------------------
------------------------------------------------------------------------
\1\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, NL =
  Not listed

    Not all these species (listed in Table 3 above) are expected to be 
harassed from the described operations. Because most of the activities 
occurring on or over land and most species are considered rare in the 
project area, only Steller sea lions and Pacific harbor seals are 
expected to be disturbed by the project.

Steller Sea Lion

    Steller sea lions range along the North Pacific Rim from northern 
Japan to California. They are most abundant in the Gulf of Alaska and 
Aleutian Islands (NMFS, 2006). Two separate stocks of Steller sea lions 
are recognized in U.S. waters; an eastern U.S. stock that includes 
animals east of Cape Suckling, Alaska (144 West), and a western U.S. 
stock which includes animals west of Cape Suckling. The western 
Distinct Population Segment (DPS) of Steller sea lions has experienced 
a major decline of 75% over the past 20 years (Calkins et al., 1999; 
USFWS, 1997; NMFS, 2007). Consequently the western DPS of Steller sea 
lions were listed as Endangered under the ESA in 1997. The reasons for 
this decline are not entirely known and are currently under 
investigation.
    Aerial survey data from 2004-2005 were used to calculate a minimum 
population estimate of 39,988 animals for the western U.S. waters 
stock. The Bering Sea/Aleutian Islands area population estimate for the 
same period is 20,578 (NMFS, 2006).
    Steller sea lions are considered non-migratory with dispersal 
generally limited to juveniles and adult males. In the Aleutian 
Islands, Steller sea lions generally breed and give birth from late May 
to early July (Pitcher and Calkins, 1981), and pups remain at rookeries 
until about early to mid-September (Calkins et al., 1999). Non-
reproductive animals congregate at haul out sites.
    At Rat Island, a persistent haul-out site is known at the west end 
of the island near Krysi Point and a rookery is known from the islet 
off Ayugadak Point. Both sites were active in 2007 (Buckelew et al., 
2007). Rat Island and the islet off Ayugadak Point, which have a haul-
out and rookery, are designated critical habitat for Steller sea lions 
and ``no entry'' zones have been established. Critical habitat includes 
a terrestrial zone and air zone, that extends 3,000 ft (914 m) 
landward, and above each major rookery and haul-out in Alaska. For the 
major rookery and haul-out west of 144 W (Ayugadak Point), critical 
habitat includes an aquatic zone that extends 20 nm (37 km) in State 
and Federally managed waters from the from the baseline or basepoint of 
the rookery and/or haul-out.
    USFWS has consulted with NMFS and NMFS determined that AMNWR did 
not need a permit to conduct routine refuge operations within the 
boundaries of the sea lion rookery closure zones and personnel 
conducting eradication operations in Steller sea lion habitat avoid 
direct confrontation. The determination relates to 50 CFR 223.202 
(b)(2) which states ``Paragraph (a) of this section does not prohibit 
or restrict a Federal, state or local government official, or his or 
her designee, who is acting in the course of official duties from: (ii) 
Entering the buffer areas to perform activities that are necessary for 
national defense, or performance of other legitimate governmental 
activities.'' The USFWS and NMFS consider rat eradication a routine 
refuge operation to which 50 CFR 223.202 is applicable.

Pacific Harbor Seal

    In the Pacific Ocean, harbor seals occur in coastal waters and 
estuaries from Baja California north along the west coast of the U.S. 
and Canada to Alaska including the Aleutian Islands, southern Bristol 
Bay and the Pribilof Islands. Harbor seals living in the Aleutian 
Islands are part of the Gulf of Alaska stock. The Gulf of Alaska stock 
has experienced significant declines ranging from 50-85% over the past 
30 years (NMFS, 2006). Limited information suggests some modest 
recovery from initial declines and the stock has not been listed under 
the ESA. The current statewide population estimate for Alaska harbor 
seals is 180,017 (NMFS, 2006).
    Harbor seals are generally non-migratory with some local movements 
related to season, weather, and food availability (NMFS, 2006). In 
Alaska, harbor seals typically give birth to a single pup between May 
and mid-July. Pups are generally weaned within one month and separate 
from their mother. Harbor seals in the Gulf of Alaska undergo an annual 
molt which peaks between the first week in August and the first week in 
September (Daniel et al., 2003). Harbor seals are found in scattered 
locations along the shores of Rat Island and some offshore islets.

                                                              Table 3. Recent survey results for pinnipeds in the Rat Island area.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                              Species                                       Number          Year                Source                                        Comments
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                            Harbor seal                                              93      1999           Small et al. in press                                                Aerial survey.
                                                                      ``Fairly common''      2007            Buckelew et al. 2007                      Often seen in water, not seen hauled out
                          Steller sea lion                                           45      2004                   NMFS database              Aerial survey for Rat Is. (adults and juveniles)
                                                                                    254      2005                   NMFS database   Aerial survey for Ayugadak Point Rookery (includes 83 pups)
                                                                                present      2007                  Buckelew, 2007           Seen from boat offshore at Rat Is. And Ayugadak Pt.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 51282]]

    Further information on the biology and distribution of these 
species and others in the region can be found in USFWS' application and 
EA, which is available upon request (see ADDRESSES), and the Marine 
Mammal Stock Assessment Reports, which are available online at https://
www.nmfs.noaa.gov/prot_res/PR2/Stock_Assessment_Program/individual_
sars.html.

Potential Effects of the Proposed Activity on the Marine Mammals

Effects of Rodenticide

    Pinnipeds are not expected to be impacted by the use of the 
rodenticide (brodifacoum) during the rat eradication operations. 
Brodifacoum is a vertebrate toxicant that is commonly used widely 
available in the United States. Most vertebrates are less susceptible 
to brodifacoum than are rats, and would have to consume a higher dose, 
relative to body mass, before reaching a toxicity threshold. The 
rodenticide bait pellets, which are primarily composed of grain, are 
not part of the natural diet of carnivorous (almost exclusively 
piscivorous) pinnipeds and therefore are not expected to be consumed. 
Also, pinnipeds are not expected to prey or scavenge on other animals 
that have consumed and succumb to the effects of the rodenticide as 
they do not feed while hauled out on land. The only possible routes for 
bait ingestion are accidental. The rodenticide bait will not be 
broadcast into the marine environment, and if it were to enter the 
water it will disperse and disintegrate within hours. The effects of 
sublethal exposure to the rodenticide is negligible and warrants little 
concern given the very slight risk during the length of the operations.

Behavioral Disturbance

    It is well known that human activity can flush pinnipeds off haul-
out sites (Allen et al., 1984; Calambokidis et al., 1991; Suryan and 
Harvey, 1999; Mortenson et al., 2000). Researchers have observed that 
human disturbances in the form of boat and aircraft traffic and people 
on the beach can flush pinnipeds into the water from haul-out sites and 
impact pinnipeds haul-out numbers (Renouf et al., 1981; Schneider and 
Payne, 1983; Terhune and Almon, 1983).
    Helicopter disturbances are mainly in the forms of airborne and 
underwater noise generated by the engine of the aircraft and the 
physical presence of the aircraft (Richardson et al., 1995; Born et 
al., 1999). Noise generated from helicopter activities may cause 
harassment of pinnipeds, both hauled out and in the water, at or 
directly below the surface. Airborne sound from a low-flying helicopter 
may be heard by marine mammals while at the surface or underwater. In 
general, helicopters tend to be noisier than fixed-wing aircraft of 
similar size, and larger aircraft tend to be louder than those that are 
smaller. Underwater sounds from aircraft are strongest just below the 
surface and directly under the aircraft. Noise from aircraft would not 
be expected to cause direct physical effects, but have the potential to 
affect behavior. The primary factor that may influence abrupt movements 
of animals is engine noise, specifically changes in engine noise.
    Studies on many wildlife species responses to aircraft approaches 
showed that flight altitude, noise output, speed, and approach pattern 
are the most important factors in determining an animal's reaction to 
an overflight (McKechnie and Gladwin, 1995).

Steller Sea Lions

    The response of pinnipeds, like Steller sea lions, to aircraft 
overflights varies from no discernable reaction to completely vacating 
haul outs after a single overflight (Calkins, 1979; Efroymson and 
Suter, 2001). Approaching aircraft generally flush animals into the 
water. In one case, Withrow et al. (1985 in Richardson et al., 1995) 
reported Steller sea lions left a beach in response to a Bell 205 
helicopter >1.6 km away, but the noise from a helicopter is typically 
directed down in a ``cone'' underneath (Richardson et al., 1995) so 
disturbance at such great distance is probably uncommon.
    At Rat Island, known persistent haul out sites will be avoided 
during staging operations as will any other haul out sites discovered 
prior to helicopter operations. In spite of these precautions, sea 
lions encountered unexpectedly during helicopter operations could be 
flushed from land temporarily. An individual sea lion's exposure to 
peak noise from the helicopter will be limited to animals that remain 
ashore, and is likely to be of short duration, as the elevation and 
speed of the helicopter will limit the time that any single location is 
exposed to maximum noise.
    It will be more difficult to avoid known haul sites on Rat Island 
with the helicopter during bait application because of the need for 
thorough coverage of the island and islet. No pups are expected on Rat 
Island. The impacts of disturbance to sea lions during molting (a 
sensitive period to disturbance, Richardson et al., 1995) will be 
minimized by timing overflights after the peak molting period is over.
    The installation of bait stations on the islet off Ayugadak Point 
in August will not occur as planned in the proposed IHA (73 FR 34705). 
The island will be baited with the helicopter as described in the EA, 
in the fall after the pupping and primary molting season. This is 
likely to result in flushing sea lions from the islet resulting in 
short-term displacement. However, as helicopter baiting will be a very 
short process (approximately 15 minutes), disturbance to Steller sea 
lions is likely to be very short-term, allowing the animals to return 
to land quickly.
    Risks to Steller sea lions from personnel camps on Rat Island will 
be minimal as camps and storage sites will be located well inland away 
from possible Steller sea lion haul-out areas.
    Overall, the effects of the operations described in the EA on 
Steller sea lions will vary depending on the number of disturbance 
events. For the purpose of estimating the potential numbers of 
pinnipeds taken by these proposed activities, NMFS assumes that 
pinnipeds that move (meaning move their whole body from one location to 
another, not just move their head from left to right, for example) or 
change the direction of their movement in response to the presence of 
the field crew personnel are taken by Level B Harassment. However, the 
short-term displacement from haul-outs that is likely to occur as a 
result of helicopter noise and personnel is not anticipated to have any 
effect on overall energy balance or fitness of any individual animals.
    It is not likely that any Steller sea lions will suffer injury or 
the potential for injury as a result of the proposed activities. The 
potential disturbance associated with the project would result in 
Steller sea lions entering the water, which they do as part of their 
normal pattern of behavior. Flushing of groups of animals at pinniped 
haul-outs is also possible. Stampeding is not anticipated to occur with 
the implementation of monitoring and mitigation measures by USFWS 
personnel. NMFS has determined that the implementation of rat 
eradication activities as described in the application and the 
Environmental Assessment (EA) will have a negligible impact on Steller 
sea lions on an individual or population level.

Pacific Harbor Seals

    The response of pinnipeds to proposed aircraft overflights varies 
from no discernable reaction to completely vacating haul outs after a 
single overflight (Calkins, 1979; Efroymson

[[Page 51283]]

and Suter, 2001). Approaching aircraft generally flush animals into the 
water.
    During staging operations, project managers will plan helicopter 
flight lines and boat travel to minimize the potential for disturbance 
to harbor seal haul-outs known from existing databases and surveys 
conducted prior to operations. However, in spite of these precautions, 
seals encountered unexpectedly during helicopter operations could be 
flushed from land temporarily. An individual seal's exposure to peak 
noise from the helicopter will be limited to animals that remain 
ashore, and is likely to be of short duration, as the elevation and 
speed of the helicopter (see Description of Activities, above) will 
limit the time that any single location is exposed to maximum noise.
    It will be more difficult to avoid known haul-out sites of Rat 
Island with the helicopter during proposed bait application because of 
the need for thorough coverage of the entire island. No young pups are 
expected on Rat Island during the fall. The impacts of disturbance to 
seals during molting (another sensitive period) will be minimized by 
timing overflights after the peak molting period is over.
    The sporadic personnel presence and temporary infrastructure 
installations that may be necessary near seal haul-outs during both 
staging and bait application operations may result in localized 
disturbances, although this is much less likely to disturb animals than 
helicopter overflights. The camps and staging areas themselves will be 
well inland and will have negligible impacts on seals hauled out on the 
coastline.
    Overall, the short-term displacement from haul-out sites that is 
likely to occur as a result of helicopter noise and personnel 
activities is anticipated to have a negligible impact on the overall 
energy balance or fitness of any individual animals.
    It is not likely that any harbor seals will suffer injury or the 
potential for injury as a result of project activities. NMFS has 
determined that the implementation of rat eradication activities as 
described in the application and the EA will have a negligible impact 
on Pacific harbor seals on an individual or population level.

Pinnipeds in the Rat Island Project Area

    Variable numbers of sea lions and harbor seals typically haul out 
near bait application sites used for eradication operations, with 
breeding activity occurring at one known site. Pinnipeds likely to be 
affected by rat eradication activity are those that are hauled-out on 
land at or near bait application sites.
    Incidental harassment may result if hauled animals move away from 
the field crew personnel, watercraft, and aircraft. For the purpose of 
estimating the potential numbers of pinnipeds taken by these proposed 
activities, NMFS assumes that pinnipeds that move (meaning move their 
whole body from one location to another, not just move their head from 
left to right, for example) or change the direction of their movement 
in response to the presence of field crew personnel activities are 
taken by Level B Harassment. Although marine mammals will not be 
deliberately approached by field crew personnel during proposed 
operations, approach may be unavoidable if pinnipeds are hauled out 
directly upon the bait application sites. If disturbed, hauled-out 
animals may move toward the water without risk of encountering 
significant hazards. In these circumstances, the risk of injury or 
death to hauled animals is very low.
    The risk of marine mammal injury or mortality associated with rat 
eradication operations increases somewhat if disturbances occur during 
breeding season, as it is possible that mothers and dependent pups 
could become separated. If separated pairs don't reunite fairly 
quickly, risks of mortality to pups (through starvation) may increase. 
Also, adult Steller sea lions may trample sea lion pups if disturbed, 
which could potentially result in the injury or death of pups. However, 
to mitigate this risk, NMFS and USFWS shall include time of year 
restrictions to limit the presence of field crew personnel activities 
to months that Steller sea lion and harbor seal dependent pups are not 
present at the bait application sites.
    The risk of marine mammal injury mortality associated with rat 
eradication operations increases somewhat if disturbances occur in 
steep areas with precipitous cliffs where pinnipeds haul-out. However, 
there are no steep or precipitous areas that animals would be flushed 
from during the operations. The beach at Krysi Point on Rat Island 
consists of mixed small boulders and cobble. The terrain behind the 
beach gradually sloped upward 38 m (125 ft). There are offshore rocks 
which the animals also use at that persistent haul-out location. The 
islet near Ayugadak Point has boulder beaches that are backed by steep 
grass covered slopes. The animals at the rookery only use the beach 
areas and do not access the steep areas. Field crew personnel are to 
use great care approaching sites with pinnipeds and will leave as soon 
as possible to minimize effects. Because of the circumstances and the 
proposed IHA requirements discussed above, NMFS believes it highly 
unlikely that the activities would result in the injury or mortality of 
pinnipeds.
    For the purposes of estimating take in the IHA, NMFS assumes that 
pinnipeds that move (meaning move their whole body from one location to 
another, not just move their head from left to right, for example) or 
change the direction of their movement in response to the presence of 
field crew personnel activities are taken by Level B Harassment. As 
discussed further in the Monitoring and Reporting section below, the 
responses of the pinnipeds will be recorded by USFWS personnel during 
the specified activities.

Comments and Responses

    On June 18, 2008 (73 FR 34705), NMFS published in the Federal 
Register a notice of a proposed IHA for USFWS' request to take marine 
mammals incidental to conducting non-native rat eradication operations 
at Rat Island, and requested comments regarding this proposed IHA 
(FRNOR). During the 30-day public comment period, NMFS received 
comments from the Marine Mammal Commission (Commission) and Judith Lee 
from Environmental Planning Strategies, Inc. (EPS).
    Commission Comment: The Commission states that because the 
applicant is requesting authority to take marine mammals by harassment 
only, NMFS should require that operations be suspended immediately if a 
dead or seriously injured marine mammal is found in the vicinity of the 
operations and the death or injury could have occurred incidental to 
the non-native rat eradication program. The Commission further 
recommends that any such suspension should remain in place until NMFS 
has: (1) reviewed the situation and determined that further mortalities 
or serious injuries are unlikely to occur; or (2) issued regulations 
authorizing such takes under section 101(a)(5)(A) of the MMPA.
    Response: NMFS concurs with the Commission's recommendations and 
has included a requirement to this effect in the IHA.
    Commission Comment: The Commission additionally recommends that 
prior to issuing the IHA, NMFS require the applicant to expand its 
monitoring plan to detect the effects of disturbance and short- and 
long- term exposure to the rodenticide, and all mitigation, monitoring, 
and reporting measures identified in the proposed notice are included 
in the IHA and the approach be supplemented by the measures described 
to avoid disturbance and detect problems that may arise after

[[Page 51284]]

the rodenticide has been dispersed over the island.
    Response: NMFS disagrees with the Commission's assessment that 
rodenticide poses any short- and long-term exposure pathway for 
harassment, injury, and/or mortality. Pinnipeds are not expected to be 
impacted by the use of rodenticide (brodifacoum) during the rat 
eradication operations. Most vertebrates are less susceptible to 
brodifacoum than are the rats, and would have to consume a higher dose, 
relative to body mass, before reaching a toxicity threshold. Therefore, 
pinnipeds would have to directly consume ten's, if not hundreds of bait 
pellets, to be affected by the rodenticide. The rodenticide bait 
pellets, which are primarily composed of grain, are not part of the 
natural diet of carnivorous (almost exclusively piscivorous) pinnipeds 
and therefore are not expected to be consumed. Also, pinnipeds are not 
expected to prey or scavenge on other animals that have consumed and 
succumb to the effects of the rodenticide as they do not feed while 
hauled out on land. The only possible routes for bait ingestion are 
accidental. The rodenticide bait will not be broadcast into the marine 
environment, and if it were to enter the water it will disperse and 
disintegrate within hours. For secondary exposure through marine fish, 
which are part of the diet of pinnipeds inhabiting Rat Island, the risk 
is similarly remote and rodenticide impacts are considered negligible. 
The number of bait pellets that will enter the marine environment as a 
result of application activities will be low as a result of the 
mitigation measures described in the EA and application for avoiding 
bait application in the ocean.
    The probability that fish will consume bait pellets is considered 
to be very low, and bait pellets will disintegrate rapidly upon contact 
with the water. In tests conducted by researchers in the Aleutians, as 
well as in California, Hawaii, and the equatorial Pacific, marine fish 
species demonstrated almost no interest in placebo bait pellets that 
entered the water nearby (Buckelew et al., 2007a; Howald et al., 2005; 
USFWS, 2005). Some marine invertebrates are also included in the diet 
of pinnipeds inhabiting Rat Island.
    Most invertebrate species are not known to be susceptible to toxic 
effects from the use of brodifacoum in the field (Hoare and Hare, 
2006). However, both marine and terrestrial invertebrates (i.e., filter 
feeders and crabs) are known to consume bait pellets. During a 
catastrophic accidental spill of 20 tons of brodifacoum into nearshore 
waters in New Zealand (Primus et al., 2005), a peak concentration of 
the toxicant measured in mussels occurring at the spill site was 0.41 
ppm one day after the spill; this equates to 1/60\th\ of the 
brodifacoum found in one pellet. Within 30 days, the concentration had 
dropped to just above 0.002 ppm or 200 times less than peak. The 
effects of sublethal exposure to the rodenticide is negligible and 
warrants little concern given the very slight risk during the length of 
the operations.
    Also, sea lions at Rat Island are not anticipated to haul-out in 
areas that include potentially dangerous steep areas or precipitous 
cliffs. The persistent haul out at Krysi Point is a beach composed of 
mixed small boulders and cobbles. Offshore rocks are used by animals. 
The terrain behind the beach gradually slopes upward to 38 m (125 ft). 
The islet near Ayugadak Point has boulder beaches backed by steep grass 
covered slopes. The animals only use the beach areas and do not access 
the steep areas. NMFS and USFWS has determined that there are no steep 
or precipitous areas that animals would be flushed from during the rat 
eradication operations. Also, monitoring and cautionary mitigation 
measures will be implemented to avoid any potential harassment and 
report and document disturbances during the authorized field crew 
activities.
    EPS Comment: EPS recommends that NMFS deny issuing the IHA for the 
rat eradication project in order to protect the endangered Steller sea 
lions on Rat Island and their designated critical habitat. The 
incidental take of Steller sea lions with and without an aerial 
application of rodenticide is unnecessary, with the potential for Level 
A harassment never discussed. Because of the excessive level, timing, 
and kind of incidental take, including the potential for Level A and 
Level B harassment, an EIS should be prepared by AMNWR for the project, 
with full and appropriate public and agency involvement and comment.
    Response: The purpose and use of rodenticide during rat eradication 
operations and its potential to not result in Level A harassment is 
discussed in the proposed IHA's FRNOR (73 FR 34705), USFWS' EA, and 
this document. The discussion of whether or not the aerial application 
of the rodenticide is necessary is outside the scope of this IHA. By 
implementing the monitoring and mitigation measures described in the 
IHA, Level A takes of marine mammals are highly unlikely and short-term 
Level B harassment would occur at most. The number of animals taken by 
Level B harassment would be considered small, and the takes will have a 
negligible impact on the species and/or stock of marine mammals. If 
needed (i.e., if the activity did result in injury, which is not 
authorized), the IHA can be modified, suspended, or withdrawn from the 
applicant. An EA prepared by USFWS for the Rat Island project was 
completed and released for full public review. Public comments were 
considered and a finding of no significant impact (FONSI) was issued by 
USFWS in March 2008. NMFS adopted the USFWS' EA and issued a FONSI. The 
NEPA requirements for the issuance of an IHA to USFWS for the Rat 
Island project have been fulfilled by NMFS.
    EPS Comment: The potential for all rodents to be exposed to 
rodenticide with the proposed project, including buffers on Rat Island 
and the rookery islet and the bait station application, is extremely 
low. The potential for reinvasion from the islet especially is 
extremely high. Therefore, the resultant high impacts/takes, including 
pups and subadults at both Level A and Level B, with little to no 
short-term or long-term positive results on Rat Island is unacceptable.
    Response: Comments regarding whether or not the rat eradication 
program is likely to be effective are outside the scope of 
determinations that NMFS must make regarding the issuance of an IHA. 
However, the Rat Island project has been planned for several years with 
several rounds of review by an independent and international team of 
experts. The methods proposed have been used to successfully eradicate 
rodents from hundreds of islands worldwide. The methods proposed for 
the Rat Island project were developed to successfully eradicate non-
native rodents while minimizing secondary impacts to wildlife. The 
AMNWR has consulted with NMFS representatives regarding the level of 
disturbance associated with the Rat Island Project. These consultations 
concluded that Level A Harassment is unlikely to result from this 
project.
    EPS Comment: Rat Island was invaded by rats over 200 years ago and 
the ecological damage has been in place for centuries- the pristine 
condition has no way to be known- so this project has little potential 
for improving the ecological condition of the island in any major way, 
with associated high levels of impacts to endangered Steller sea lions.
    Response: Whether or not the project has the potential to improve 
the ecological condition of the island is outside the scope of the IHA. 
However,

[[Page 51285]]

the application indicated that most of the islands in the Aleutian 
archipelago, including those very near Rat Island, do not have rats and 
provide a good indication of what the island was like prior to the 
introduction of rats. If rats are successfully removed, habitat is 
anticipated to recover and native wildlife species will likely re-
colonize the island. The USFWS and its partners would not commit the 
time, staff, funding, and other resources to a project that had no 
tangible natural resource benefits. National Wildlife Refuge System 
lands are mandated to be managed for natural biodiversity.
    EPS Comment: EPS states that sufficient time has not been allowed 
to plan, monitor, stage, or implement the project sufficiently for 
implementation in September or even November 2008. Losing funding is 
not an appropriate reason to rush a project that is complex, 
logistically extremely difficult, has a high potential for failure, has 
high potential for unacceptable impacts, including injury and possibly 
death to individual Steller sea lions on Rat Island and at the rookery, 
and is on an extremely large island on which neither the USFWS nor 
Island Conservation has ever attempted an aerial broadcast.
    Response: This project has been planned for several years with 
guidance from and review by an independent, international team of 
experts. The equipment, supplies, and staff needed for the project to 
be successful have been secured. The AMNWR and its partners have many 
years of experience operating in the Aleutian Islands, fully understand 
the challenges associated with a project of this magnitude and expect 
to be successful. Also, as mentioned previously, NMFS does not expect 
the planned activity to result in the injury or death of any marine 
mammals.
    EPS Comment: EPS states that the impacts and takes of marine 
mammals could be higher than evaluated in the application based on pre- 
and post- monitoring activities and conducted surveys; and suggests 
that monitoring activities should occur over many years. EPS also 
states that takes could be higher than evaluated in the application 
based on and the potential for fuel spills during staging and after 
project completion.
    Response: Based on aerial surveys conducted at Rat Island and on 
the islet off of Ayugadak Point, NMFS determined that numbers of 
pinnipeds potentially taken by Level B harassment incidental to rat 
eradication operations is small relative to the population of the 
species and stock. Activities related to pre- and post project 
activities have not and will not result in the take of any marine 
mammals. Due to the remote location of Rat Island as well as the 
inclement and unpredictable weather in the region, long term pre- and 
post- monitoring activities would be very difficult to conduct. Marine 
mammal take related to the Rat Island project is expected to be much 
lower than requested in the IHA application and will be carefully 
monitored. Fuel for the Rat Island project will be handled in 
accordance with all applicable laws and USFWS Region 7 Fuel Policy. 
Fuel storage areas will use secondary containment that prevents a 
catastrophic release into the environment. Spill response equipment and 
40 hour HAZWOPER trained personnel will be available to all locations 
where fuel is located and on the Refuge research vessel to be used in 
the unlikely event of a fuel spill.

Incidental Take Authorization Requested

    The rat eradication effort and associated operations may result in 
the taking of marine mammals by Level B incidental harassment only. As 
a result, the USFWS has requested an IHA for Level B harassment. For 
this authorization, Level B harassment occurs if an animal moves away 
any distance in response to the presence of field crew personnel, 
watercraft, and/or aircraft, or if the animals was already moving and 
changed direction. Animals that raise their head and look at field crew 
personnel and/or operated vehicle without moving are not considered 
disturbed. Most incidental takings will be related to harassment from 
the noise and visual presence/movement of helicopter operations during 
the bait application period. A small number of takes could also occur 
as a result of human presence and boat operations during the course of 
the project.
    Level A take (i.e., injury or mortality) due to stampeding or 
mother-pup separation is not anticipated during the rat eradication 
operations. Since the activities will occur after the rookery season, 
the abundance of pinnipeds should be lower. Injuries or mortalities by 
stampedes due to field crew personnel, watercraft, and/or aircraft 
approaches are not anticipated because animals are likely to be more 
spaced apart, thus when being flushed into the water, it is not likely 
that they would trample one another.
    The use of a rodenticide is not expected to result in any Level A 
harassment or death of marine mammals. Marine mammals are unlikely to 
ingest bait pellets of rodenticide opportunistically or accidentally 
because they are strictly carnivorous and are not carrion eaters. 
Additionally, the rodenticide is retained at low levels in body tissues 
and numerous large exposures (on the order of directly consuming tens 
to hundreds of bait pellets) would have to occur in order to result in 
injury or death. Based on their known dietary habits, Steller sea lions 
and harbor seals are not expected to ingest either bait pellets or rat 
carcasses resulting from rodenticide application.

Estimated Number of Marine Mammal Takes

    As discussed above, NMFS anticipated that take of marine mammals 
will occur in the form of disturbance resulting from the presence of 
helicopters, vessel or pedestrian traffic in the vicinity of the 
pinnipeds. As also discussed above, no take is expected to result from 
exposure to rodenticide.

Rat Island

    Most of the disturbance associated with the Rat Island eradication 
will be a result of aircraft noise. The helicopters used to apply bait 
to the island will make two passes across most of the island to ensure 
success of the project. This could result in two harassment incidents 
of Steller sea lions and harbor seals that are hauled out at that time. 
The area surrounding a known Steller sea lion haul out at Krysi Point 
will be avoided by all activities other than bait application. Harbor 
seals use many parts of Rat Island shoreline and could also be affected 
by boat operations and personnel movements. Thus the number of takes 
was estimated at 2.5 for each individual of this species to account for 
their sporadic distribution in the water and at haul-outs around the 
island.
    Steller sea lions at Rat Island were counted during an aerial 
survey in 2004. The number of animals counted during that survey was 
increased to allow for potential population growth and then used to 
calculate the total take in Table 4 (below).
    The composition of Steller sea lions, which haul out away from 
rookeries, shifts between seasons and is not well understood. Although 
no pups are expected at Rat Island, determining the age and sex ratio 
of animals using the known haul out near Krysi Point in October is 
difficult at best. For this reason the number is calculated as adult 
and sub-adult animals without reference to the sex of these animals.
    Harbor seals at Rat Island were counted by an aerial survey in 1999 
(see Table 4). The number of animals (93 individuals) recorded during 
that survey

[[Page 51286]]

was increased to allow for potential population growth and then used to 
calculate the total take in Table 4 (below). Information regarding the 
demographics of harbor seals on Rat Island is not available. The number 
of animals recorded in the 1999 survey was used to calculate a total 
number of harbor seal takes.

                                                   Table 4. Estimated number of marine mammals affected by aircraft operations on Rat Island.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                     of       of                   Pups                              Subadults                            Adults
             Species               animals at Rat    take events per ----------------------------------------------------------------------------------------------------------- Total 
                                       Island            animal                                                   M                 F                 M                F             of Takes
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Steller sea lion                  65                2                 0                 0                 -                 -                 -                 -                130
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Pacific harbor seal               100               2.5               0                 0                 -                 -                 -                 -                250
------------------------------------------------------------------------------------------------------------------------------------------------------