[Federal Register Volume 85, Number 44 (Thursday, March 5, 2020)]
[Notices]
[Pages 12898-12905]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-04481]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[Docket No. 200226-0065; RTID 0648-XR088]
Endangered and Threatened Species; Determination on the
Designation of Critical Habitat for Oceanic Whitetip Shark
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice.
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SUMMARY: We, NMFS, have determined that a designation of critical
habitat under the Endangered Species Act (ESA) for the oceanic whitetip
shark (Carcharhinus longimanus) is not prudent at this time. Based on a
comprehensive review of the best scientific data available, we find
there are no identifiable physical or biological features that are
essential to the conservation of the oceanic whitetip shark within
areas under U.S. jurisdiction. We also find that there are no areas
outside of the geographical area occupied by the species under U.S.
jurisdiction that are essential to its conservation. As such, we find
there are no areas within the jurisdiction of the United States that
meet the definition of critical habitat for the oceanic whitetip shark.
DATES: This finding is made on March 5, 2020.
ADDRESSES: Electronic copies of the determination, list of references,
and supporting documents prepared for this action are available from
the NMFS Office of Protected Resources website at https://www.fisheries.noaa.gov/species/oceanic-whitetip-shark.
FOR FURTHER INFORMATION CONTACT: Adrienne Lohe, NMFS, Office of
Protected Resources, (301) 427-8403.
SUPPLEMENTARY INFORMATION:
Background
On January 30, 2018, we published a final rule to list the oceanic
whitetip shark (Carcharhinus longimanus) as a threatened species under
the ESA (83 FR 4153). Section 4(b)(6)(C) of the ESA requires the
Secretary of Commerce
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(Secretary) to designate critical habitat concurrently with making a
determination to list a species as threatened or endangered unless it
is not determinable at that time, in which case the Secretary may
extend the deadline for this designation by 1 year. In our proposal to
list the species as threatened (81 FR 96304, Dec. 29, 2016), we
requested relevant information from interested persons to help us
identify and describe the physical and biological features essential to
the conservation of the oceanic whitetip shark, and assess the economic
impacts of designating critical habitat for the species. We solicited
input from the public, other governmental agencies, the scientific
community, industry, environmental groups, and any other interested
parties on features and areas that may meet the definition of critical
habitat for the oceanic whitetip shark within U.S. waters. However, at
the time of listing, and based on comments provided and the best
available scientific information, we concluded that critical habitat
was not determinable because: (1) Sufficient information was not
available to assess the impacts of designation; and (2) sufficient
information was not available regarding the physical and biological
features essential to conservation. We again requested interested
persons to submit relevant information related to the identification of
critical habitat and essential physical or biological features for this
species, as well as economic or other relevant impacts of designation
of critical habitat for the oceanic whitetip shark. Though we did not
receive any information relevant to the designation of critical habitat
in response to this request, we used the best available scientific data
to evaluate whether critical habitat could be identified for the
oceanic whitetip shark. As discussed below, we still find that there
are no identifiable physical or biological features that are essential
to the conservation of the oceanic whitetip shark within areas under
U.S. jurisdiction, or unoccupied areas under U.S. jurisdiction that are
essential to the conservation of the species. Therefore, at this time
we find no areas within U.S. jurisdiction that meet the definition of
critical habitat for the oceanic whitetip shark.
This finding describes information on the biology, distribution,
and habitat use of the oceanic whitetip shark and the methods used to
identify areas that may meet the definition of critical habitat. In
this determination, we focus on information directly relevant to the
designation of critical habitat for oceanic whitetip sharks.
Oceanic Whitetip Shark Biology and Status
The following discussion of the life history and status of the
oceanic whitetip shark is based on the best scientific data available,
including the ``Endangered Species Act Status Review Report: Oceanic
Whitetip Shark (Carcharhinus longimanus)'' (Young et al. 2017).
The oceanic whitetip shark is a large, pelagic species of shark,
described historically as one of the most abundant shark species in
tropical waters worldwide (Mather and Day 1954; Backus et al. 1956;
Compagno 1984). The oceanic whitetip shark belongs to the family
Carcharhinidae and is a member of the genus Carcharhinus, which
includes other pelagic species of sharks, such as the silky shark (C.
falciformis) and dusky shark (C. obscuras).
The oceanic whitetip shark is globally distributed and can be found
in all ocean basins in epipelagic tropical and subtropical waters. The
species can be found offshore, along the edges of continental shelves,
or around oceanic islands in deep water (Backus et al. 1956; Strasburg
1958; Compagno 1984; Bonfil et al. 2008) and appears to be thermally
sensitive, exhibiting a strong preference for the surface mixed layer
in warm waters above 20 [deg]C (Bass et al. 1973; Bonfil et al. 2008).
Several archival satellite tagging studies from various regions of the
species' range indicate that oceanic whitetip sharks spend most of
their time at depths of less than 200 m (above the thermocline) (Musyl
et al. 2011; Carlson and Gulak 2012; Howey-Jordan et al. 2013; Tolotti
et al. 2017). The oceanic whitetip is generally thought to be a long-
lived species, ranging from 12 to 18 years in the North Pacific and
Western and Central Pacific, respectively (Joung et al. 2016; D'Alberto
et al. 2017), and 13 to 19 years in the South Atlantic (Seki et al.
1998; Lessa et al. 1999; Rodrigues et al. 2015), with relatively low
reproductive output.
Similar to other carcharhinid species, the oceanic whitetip shark
is viviparous (i.e., gives birth to live young) with placental
embryonic development. Reproductive periodicity is thought to be
biennial, with individuals giving birth on alternate years after a 10-
12 month gestation period (Backus et al. 1956; Seki et al. 1998;
Tambourgi et al. 2013). However, recent unpublished data obtained via
ultrasonography of pregnant females over multiple years suggests that
at least for a proportion of the population, reproduction could be
annual (James Gelsleichter, University of North Florida, unpublished
data). Litter sizes range from 1 to 14 (average of 6), and there is a
positive correlation between female size and number of pups per litter,
with larger sharks producing more offspring (Backus et al. 1956;
Strasburg 1958; Bass et al. 1973).
In terms of movement, the oceanic whitetip shark is considered to
be a highly migratory species, with several satellite tracking studies
measuring long distance movements of up to 4,285 km (Musyl et al. 2011)
and over 6,000 km in the open ocean (Filmalter et al. 2012). Although
the species is considered highly migratory and capable of making long
distance movements, data from pop-off satellite archival tags provides
evidence that this species also exhibits a high degree of philopatry in
some locations (e.g., Cat Island, Bahamas and Northeast Brazil) (Howey-
Jordan et al. 2013; Tolotti et al. 2015). Overall, oceanic whitetip
sharks are highly mobile and can travel great distances in the open
ocean (Filmalter et al. 2012), with excursion estimates of several
thousand kilometers demonstrated in multiple studies. However,
information on potential migratory corridors and seasonality is
lacking.
As discussed in the proposed rule (81 FR 96304, December 29, 2016)
and final rule (83 FR 4153, January 30, 2018) to list the oceanic
whitetip shark, the most significant threat to the species is
overutilization for commercial purposes. Although oceanic whitetip
sharks are not necessarily a targeted species, they are caught as
bycatch in a number of fisheries throughout their range, and are most
susceptible to industrial longline fisheries. Oceanic whitetip shark
fins are also prevalent in the international fin trade, which has
likely contributed to the significant declines of the species
throughout its range. Given the relatively low reproductive output and
overall productivity of the oceanic whitetip shark, it is inherently
vulnerable to threats that would deplete its abundance, with a low
likelihood of recovery. Therefore, while there is considerable
uncertainty regarding the current abundance of oceanic whitetip sharks
throughout its entire range, the best available information indicates
that the species is likely to become an endangered species within the
foreseeable future due to overutilization.
Critical Habitat Identification and Designation
Critical habitat is defined by section 3 of the ESA as (i) the
specific areas within the geographical area occupied by the species, at
the time it is listed, on which are found those physical or
[[Page 12900]]
biological features (I) essential to the conservation of the species
and (II) which may require special management considerations or
protection; and (ii) specific areas outside the geographical area
occupied by the species at the time it is listed upon a determination
by the Secretary that such areas are essential for the conservation of
the species. This definition provides a step-wise approach to
identifying areas that may qualify as critical habitat for the oceanic
whitetip shark: (1) Determine the geographical area occupied by the
species at the time of listing; (2) identify physical or biological
habitat features essential to the conservation of the species; (3)
delineate specific areas within the geographical area occupied by the
species on which are found the physical or biological features; (4)
determine whether the features in a specific area may require special
management considerations or protection; and (5) determine whether any
unoccupied areas are essential for conservation. Our evaluation and
conclusions as we worked through this step-wise process are described
in detail in the following sections.
Geographical Area Occupied by the Species
The ``geographical area occupied by the species'' is defined in our
regulations as an area that may generally be delineated around species'
occurrences, as determined by the Secretary (i.e., range). Such areas
may include those areas used throughout all or part of the species'
life cycle, even if not used on a regular basis (e.g., migratory
corridors, seasonal habitats, and habitats used periodically, but not
solely by vagrant individuals). (50 CFR 424.02). Further, our
regulations at 50 CFR 424.12(g) state that the Secretary will not
designate critical habitat within foreign countries or in other areas
outside of the jurisdiction of the United States. As such, we cannot
designate critical habitat for the oceanic whitetip outside of U.S.
waters and will focus the following discussion on the U.S.
jurisdictions where the oceanic whitetip shark is known to occur.
Northwest Atlantic and Caribbean
The geographic range of the oceanic whitetip shark in the Northwest
Atlantic and Caribbean is reportedly very broad, occurring from Maine
to Florida on the East Coast, in the Gulf of Mexico and in U.S.
Territorial waters within the Caribbean (U.S. Virgin Islands and Puerto
Rico) (Compagno 1984). However, the NMFS Northeast Fisheries Science
Center (NEFSC) describes this species as ``uncommon'' in the U.S.
Atlantic EEZ (NMFS 2017). Essential fish habitat (EFH; defined under
the MSA as those waters and substrate necessary to fish for spawning,
breeding, feeding or growth to maturity (16 U.S.C. 1802(10))), has been
designated for the oceanic whitetip shark in waters greater than 200 m
in depth from offshore of the North Carolina/Virginia border to the
Blake Plateau, which is a broad, relatively flat portion of the upper
continental slope that extends from the coast of North Carolina to
central Florida. Essential fish habitat was not designated north of
Virginia (NMFS 2017). Designated EFH in the Gulf of Mexico includes
offshore habitats of the northern Gulf of Mexico at the Alabama/Florida
border (e.g., the Mississippi plume shows high occurrence of juveniles
and adults) to offshore habitats of the western Gulf of Mexico south of
eastern Texas. Additionally, the entire U.S. Caribbean (waters of
Puerto Rico and the U.S. Virgin Islands) is considered to be EFH for
the oceanic whitetip shark (NMFS 2017). These designations were based
on high encounters of the species in fisheries observer data from the
U.S. pelagic longline fishery as well as recent movement data from
archival satellite tags (NMFS 2017), which confirms the historical and
current presence of oceanic whitetip sharks in these waters. Areas of
high occurrence are also off the east coast of Florida, Charleston Bump
off the southeast United States, and between Florida, Cuba and the
Yucatan Peninsula (J. Carlson, unpublished analysis, 2019). However,
while we can confirm that the geographical areas occupied by the
oceanic whitetip include U.S. waters, there is no information regarding
the specific habitat use of oceanic whitetip sharks in any of these
areas (J. Carlson, NMFS Southeast Fisheries Science Center pers. comm.
to C. Young, NMFS OPR, 2017), and nurseries and pupping grounds have
not been identified in U.S. waters (NMFS 2017; CITES 2013).
Eastern Pacific
In the eastern Pacific, the oceanic whitetip shark reportedly
occurs from southern California to Peru, including the Gulf of
California and Clipperton Island (Compagno 1984). While its eastern
Pacific range reportedly extends as far north as southern California,
this is likely due to warm water incursions that allow the species to
venture into waters far beyond its normal range (Compagno 1984). Ebert
et al. (2017) notes that oceanic whitetip sharks are ``rare'' in
southern California waters, usually observed around the Channel Islands
during warm water years. Observer data of the West Coast-based U.S.
fisheries further confirm this finding, with oceanic whitetip sharks
not observed in the catches. For example, in the California/Oregon
drift gillnet fishery, which operates off the U.S. Pacific coast from
the U.S./Mexican border to waters off of Oregon, observers recorded
zero oceanic whitetip sharks in 8,698 sets conducted over the past 25
years (from 1990-2015; Young et al. 2017). We have no other information
to suggest that oceanic whitetip sharks regularly occupy the waters of
southern California or elsewhere along the U.S. West Coast. Based on
the best available data, the distribution of the species appears to be
concentrated in areas farther south in foreign waters or the high seas.
For example, fisheries data from the eastern Pacific tuna purse seine
fishery shows catches of oceanic whitetip are concentrated in the area
between 10[deg] North and 10[deg] South, despite sets in more northerly
waters (Hall and Roman 2013). Other fisheries data confirm the presence
of oceanic whitetip sharks in waters off of Costa Rica, Ecuador and
Peru (Arauz 2017; Martinez-Ortiz et al. 2015; Gonzalez-Pestana et al.
2014). Although areas of southern California seem to be outside of the
core tropical distribution of oceanic whitetip sharks and are used only
during rare weather events that cause warm water incursions, we still
consider this area to be part of the species' range. However, given the
extremely limited data and seemingly limited use of this part of their
range, we are unable to identify any features of the area that are
essential to the conservation of the oceanic whitetip shark.
Western and Central Pacific
The range of oceanic whitetip sharks in the Western and Central
Pacific is broad, occurring throughout the region between 30[deg] N to
35[deg] S, with catches of the species most frequently occurring in the
central North Pacific south of 20[deg] N latitude and some individuals
occurring in more northerly locations (Clarke 2011; Clarke et al.
2011a). This range encompasses U.S. waters of Hawaii, Guam, American
Samoa, Commonwealth of the Northern Mariana Islands (CNMI), and the
Pacific Remote Island Areas. Fisheries data from a number of sources
confirm the occurrence of the oceanic whitetip shark in all of these
waters under U.S. jurisdiction (Brodziak et al. 2013; Clarke et al.
2011a; Clarke et al. 2011b; Lawson 2011; Walsh and Clarke 2011). As
such, we conclude that waters under the aforementioned U.S.
jurisdictions throughout the Western and Central
[[Page 12901]]
Pacific are geographical areas occupied by the species, though we are
unable to identify any features of the area that are essential to the
conservation of the oceanic whitetip shark.
In summary, based on the information above, we consider the
geographical areas occupied by the oceanic whitetip shark in the
Atlantic at the time of listing to include waters under U.S.
jurisdiction off the U.S. East Coast, Gulf of Mexico, U.S. Virgin
Islands, and Puerto Rico. We consider the geographical areas occupied
by the oceanic whitetip shark in the Pacific to include waters under
U.S. jurisdiction off southern California, Hawaii, American Samoa,
Guam, CNMI, and the Pacific Remote Island Areas.
Physical or Biological Features Essential for Conservation
Within the geographical area occupied by an endangered or
threatened species at the time of listing, critical habitat consists of
specific areas upon which are found those physical or biological
features essential to the conservation of the species and that may
require special management considerations or protection. The ESA does
not specifically define physical or biological features; however, court
decisions and joint NMFS-USFWS regulations at 50 CFR 424.02 provide
guidance on how physical or biological features are expressed.
Specifically, these regulations state that the physical and biological
features are those that are essential to support the life-history needs
of the species, including but not limited to, water characteristics,
soil type, geological features, sites, prey, vegetation, symbiotic
species, or other features. A feature may be a single habitat
characteristic, or a more complex combination of habitat
characteristics. Features may include habitat characteristics that
support ephemeral or dynamic habitat conditions. Features may also be
expressed in terms relating to principles of conservation biology, such
as patch size, distribution distances, and connectivity. (50 CFR
424.02).
Section 3 of the ESA (16 U.S.C. 1532(3)) defines the terms
``conserve,'' ``conserving,'' and ``conservation'' to mean: To use and
the use of all methods and procedures which are necessary to bring any
endangered species or threatened species to the point at which the
measures provided pursuant to this chapter are no longer necessary. For
oceanic whitetip sharks, we consider conservation to include the use of
all methods and procedures necessary to bring oceanic whitetip sharks
to the point at which factors related to population ecology and vital
rates indicate that the species is recovered in accordance with the
definition of recovery in 50 CFR 402.02. Important factors related to
population ecology and vital rates include population size and trends,
range, distribution, age structure, gender ratios, age-specific
survival, age-specific reproduction, and lifetime reproductive success.
Based on the available knowledge of oceanic whitetip shark population
ecology and life history, we have identified four biological behaviors
that are critical to the goal of increasing survival and population
growth: (1) Foraging, (2) pupping, (3) breeding, and (4) migration. In
the following section, we evaluate whether there are physical and
biological features of the habitat areas known or thought to be used
for these behaviors that are essential to the species' conservation
because they facilitate or are intimately tied to these behaviors and,
hence, support the life-history needs of the species. Because these
behaviors are essential to the species' conservation, facilitating or
protecting each one is considered a key conservation objective for any
critical habitat designation for this species.
Physical and Biological Features of Foraging Habitat That Are Essential
to the Conservation of the Species
Oceanic whitetip sharks are top-level predators in pelagic
ecosystems and feed primarily on pelagic teleosts (bony fish) and
cephalopods (mostly squids), but are also known to consume sea birds,
marine mammals, other sharks and rays, molluscs, crustaceans, large
sportfish, and even garbage (Madigan et al. 2015; Bonfil et al. 2008;
Cort[eacute]s 1999; Backus et al. 1956). Based on the species' diet,
the oceanic whitetip shark has a high trophic level, scoring 4.2 out of
a maximum 5.0 (Cort[eacute]s 1999). Although typically solitary,
oceanic whitetip sharks have been observed aggregating around food
sources (Bonfil et al. 2008). Historically, oceanic whitetip sharks
were described as pests to pelagic longline fisheries for tuna, as the
sharks would persistently follow boats and cause significant damage to
the catches (Compagno 1984). Oceanic whitetips have also been observed
scavenging off dead marine mammal carcasses off South Africa (Bass et
al. 1973) and feeding opportunistically on recreationally caught
sportfish in the Bahamas (Madigan et al. 2015). In fact, Madigan et al.
(2015) suggested that abundance and availability of large pelagic
teleosts in waters off Cat Island, Bahamas might be a possible
mechanism driving site-fidelity and aggregation of oceanic whitetip
sharks in the region. Additionally, results showed spatiotemporal
variation in feeding habits of the species, with short-term (i.e., near
Cat Island) diets comprised mostly of larger pelagic teleosts, and
long-term diets (>1 year) comprised mostly of squid, teleosts, and
small foraging fish (Madigan et al. 2015). However, although site
fidelity to Cat Island has been demonstrated via satellite tracking
data (Howey-Jordan et al. 2013) the reasons driving this site fidelity
(e.g., foraging, navigation, pupping, mating, etc.) are unknown at this
time. See The Physical and Biological Features of Migratory Habitat
That Are Essential to the Conservation of the Species section below for
more information. Based on the foregoing information, the oceanic
whitetip shark appears to be an opportunistic predator that is not
limited in its foraging habitats and feeds on whatever prey is
available.
Aside from the observations described above, there is no
information regarding established foraging grounds for the oceanic
whitetip shark. Recent tracking studies from the Bahamas, Brazil, and
the Indian Ocean have revealed complex vertical movements in the
species and diel behavior changes (Papastamatiou et al. 2018; Tolotti
et al. 2017; Howey et al. 2016). Based on tracking data from the
Bahamas, oceanic whitetip sharks regularly exhibit mesopelagic
excursions (defined as >=5 consecutive depth records below the 200 m
isobaths), particularly during dusk periods that may be related to
foraging (Howey et al. 2016). Tolotti et al. (2017) noted that deep
dives below 150 m were rare, but the variation seen in the shark's
vertical movement patterns could be linked to prey distribution as
well. Papastamatiou et al. (2018) further reaffirms this possibility
with evidence from oceanic whitetip sharks outfitted with cameras.
Potential prey (mackerel, scad and squid) were observed during dives
(as opposed to when individuals were in shallow water) and at the apex
of the dive when bursts of speed were common (Papastamatiou et al.
2018). Squid and other cephalopods are likely an important prey species
for the oceanic whitetip shark; Cortes (1999) and Madigan et al. (2015)
both reported that cephalopods comprise approximately 44 percent of the
oceanic whitetip shark's regular diet. Additionally, oceanic whitetip
sharks have been associated with short-finned pilot whales
(Globicephala macrorhynchus) of which squid is a main prey source
(Bester, n.d.). Although the reason for this behavior is
[[Page 12902]]
unknown, it is thought to be prey-related, as pilot whales are
extremely efficient at locating food sources (Migura and Meadows 2002).
The diel vertical migrations of oceanic whitetip sharks are similar to
and may overlap with the diel vertical migrations and/or distribution
of many species of mesopelagic and bathypelagic squids (see original
reference in Howey et al. 2016). As such, it is possible these
mesopelagic excursions represent a foraging strategy for seeking out
prey, such as squid. Although the species of squid consumed by oceanic
whitetips are unknown, many species have a wide geographic
distribution, moving throughout the deep waters of the ocean, and,
therefore, it is difficult to link these prey species to any
``specific'' areas within the oceanic geographic areas occupied.
Additionally, there was no site-specific correlation with the
mesopelagic dives undertaken by oceanic whitetips tagged in the
Bahamas. Individuals not only made consistent dives year-round near the
aggregation site in the Bahamas, but also during migrations (Howey et
al. 2016). Clear temporal or spatial patterns of vertical movements
could also not be identified in individuals tagged in Brazil or the
Indian Ocean, as behaviors alternated regularly and there was no
evident pattern across the time series of the study (Tolotti et al.
2017). Overall, although it is hypothesized that these mesopelagic
excursions are for purposes of foraging, this theory has not been
confirmed.
Overall, the best available information indicates that oceanic
whitetip sharks are opportunistic feeders and may exhibit behavioral
plasticity when encountering different prey types (Papastamatiou et al.
2018). The species does not appear to be associated with any specific
foraging grounds, adapting to its present habitat by feeding on
whatever prey are available and even scavenging on whale carcasses when
available. There does not appear to be a specific prey species that is
required to be present in a habitat for successful foraging to occur,
nor are there any specific habitat characteristics that appear to be
intimately tied with feeding behavior. As such, we are unable to
identify any particular physical or biological features of areas that
facilitate successful foraging. Further, no oceanic whitetip sharks
have been observed foraging in the geographic areas under U.S.
jurisdiction, aside from opportunistic depredation on the catch of
pelagic longline fisheries. For the foregoing reasons, it is not
possible to identify any specific areas within waters under U.S.
jurisdiction with physical or biological features related to foraging
that are essential to the conservation of the species.
Physical and Biological Features of Pupping Habitat That Are Essential
to the Conservation of the Species
Because the oceanic whitetip shark is a pelagic species that spends
most of its time offshore in the open ocean (Compagno 1984) and is one
of the few species that may complete its entire life cycle in open
water, there is limited information regarding the species' life history
and biology. Studies from the Northwest Atlantic and Indian Ocean
estimate that oceanic whitetip sharks give birth from late spring to
summer (Backus et al. 1956; Bass et al. 1973, Compagno 1984; Bonfil et
al. 2008). Based on ultrasonography, Gelsleichter (unpublished)
suggests pupping occurs in the Bahamas in May and June. In contrast,
Seki et al. (1998) found no apparent parturition period in the North
Pacific, as embryos were observed in almost every month in which data
was collected. In the Southwest Atlantic, oceanic whitetips likely give
birth in the latter half of the year, potentially from September to
November (Tambourgi et al. 2013) although Amorim (1998) found full-term
embryos from July to November, which may indicate a relatively extended
pupping period for this species, as was observed in the North Pacific
by Seki et al. (1998) (Tambourgi et al. 2013). Additionally, recent
conflicting results regarding the species' reproductive periodicity
(i.e., whether oceanic whitetip sharks give birth annually or
biannually), may indicate the possibility of non-specific pupping
seasons for this species (Clarke et al. 2015). Clarke et al. (2015)
notes that pregnant females are often found close to shore,
particularly around oceanic Caribbean Islands, which suggests that
females may come close to shore to pup. However, the specific locations
of pupping grounds and nurseries have not been identified for the
oceanic whitetip shark, and habitat requisites of these areas, such as
temperature, depth, and substrate, are unknown.
To date, neither pupping grounds nor nursery areas have been
identified definitively in the Atlantic for the oceanic whitetip shark.
Only generalized descriptions of ``potential'' pupping and nursery
areas are available, based largely on observations of young of the year
(YOY) and juvenile sharks in fisheries catch data. For example,
observations of YOY oceanic whitetips in fisheries catches off
Northwest Cuba (Vald[eacute]s et al. 2016) and observations of very
small juveniles in the waters off Haiti (Jamie Aquino, Haiti Ocean
Project, pers. comm. to C. Young, NMFS OPR, 2019) may indicate
potential pupping/nursery areas in these regions. However, these areas
are outside U.S. jurisdiction and cannot be designated as critical
habitat for the species. In addition, while the available information
suggests that there are several regions outside U.S. jurisdiction with
potential pupping grounds, there is insufficient information to
identify the essential physical or biological features for pupping
grounds. Within U.S. waters, an area of pelagic waters over the
continental shelf running along the southeastern coast of the United
States has been described as a potential nursery area based solely on
observations of young oceanic whitetip sharks offshore in this general
area (NMFS 2017). In determining the revised EFH designation for the
oceanic whitetip shark, which was based on fisheries observer and
archival satellite tagging data (NMFS 2017), high encounters of YOY
seem to occur over the continental shelf from North Carolina to
Florida, and in other pockets in the central Gulf of Mexico and north
of the U.S. Virgin Islands (J. Carlson, NMFS SEFSC, pers. comm. to C.
Young, NMFS OPR, 2019). High juvenile encounters seem to occur in
similar areas along the U.S. East Coast, with another area of
occurrence to the north of Puerto Rico and moderate usage of waters
north and south of the U.S. Virgin Islands (J. Carlson, NMFS SEFSC,
pers. comm. to C. Young, NMFS OPR, 2019). Although these areas could
represent nursery grounds for the oceanic whitetip shark, oceanic
whitetip sharks have not been observed pupping in these areas and more
importantly, we are unable to determine the physical or biological
features that are essential for pupping. Using the nursery area
identification criteria proposed by Heupel et al. (2007) and validated
by Froeschke et al. (2010), areas described above meet the first
criteria (newborn or YOY sharks are more commonly encountered in the
area than in other areas), though data regarding the second two
criteria (newborn or YOY sharks have a tendency to remain or return for
extended periods; the area or habitat is repeatedly used across years,
whereas others are not) are insufficient for a complete analysis.
Further, in the EFH designation for oceanic whitetip sharks in the
Atlantic, insufficient information prevented any differentiation
between EFH areas for neonate/juvenile and adult size classes,
resulting in a
[[Page 12903]]
combined EFH designation for all size classes (NMFS 2017). This
emphasizes the lack of information regarding any potential pupping and
nursery habitat for the species in U.S. waters of the Atlantic.
As described previously, oceanic whitetip sharks in the Western and
Central Pacific are distributed throughout the region from 30[deg] N
and 30[deg] S, but are concentrated in warm equatorial waters between
10[deg] N and 10[deg] S. Although limited information suggests there
are some areas that may serve as potential pupping grounds,
descriptions are fairly general and whether these areas occur in waters
under U.S. jurisdiction is uncertain. Records of pregnant females and
newborns are concentrated between the equator and 20[deg] N, and
between 170[deg] E to 140[deg] W, with higher concentrations in the
central part of this distribution just north of 10[deg] N (Bonfil et
al. 2008; CITES 2013). This area is a large swath of ocean that
partially overlaps the EEZs of Hawaii and several of the U.S. Pacific
Remote Island Areas (Johnston Atoll, Palmyra, Jarvis Island, Howland &
Baker Islands, and potentially Wake Island). Seki et al. (1998)
observed small neonates (<60 cm precaudal length) in a narrow band
between 10[deg]N and 20[deg] N, including waters south of Hawaii, and
concluded that there is an oceanic whitetip nursery ground in the
``oceanic region'' of the North Pacific. Bonfil et al. (2008)
reaffirmed that newborn oceanic whitetips occur mainly in a narrow
strip in the central Pacific slightly north of 10[deg] N. This, coupled
with higher concentrations of pregnant females, suggest a pupping
ground for oceanic whitetip may exist in the central Pacific between
150[deg] W and 180[deg] W and just above 10[deg] N, but a more refined
definition of the area is not possible due to incomplete sampling
(Bonfil et al. 2008). More recent analyses of fisheries catch data
determined that juveniles tend to occur in waters near the equator to
the west, just north of the northeastern islands of Papua New Guinea
and the Solomon Islands (Clarke 2011; Clarke et al. 2011a). As in the
Atlantic areas, though YOY oceanic whitetip sharks have been more
commonly encountered in these areas, there is insufficient data to
apply Heupel et al.'s (2007) second and third criteria for identifying
pupping areas in the Pacific. Other than generalized descriptions of
potential nursery area locations, which are based on fisheries
encounters of neonates, juveniles, and pregnant females, there is
inadequate information to identify any physical or biological features
of these areas that would be necessary to facilitate successful pupping
behavior for the species.
Overall, while some waters under U.S. jurisdiction may overlap with
general areas identified as potential pupping or nursery grounds for
the species, the descriptions of these areas are fairly vague (e.g.,
pelagic waters over continental shelves, oceanic areas, etc.) and are
based solely on high encounters with various size classes of the
species. We have no other information to specify the locations of these
areas within U.S. waters or identify any physical or biological
features within these areas that are essential to support the life-
history needs of the oceanic whitetip shark. As such, we cannot
identify any specific essential features that define pupping habitat
for the oceanic whitetip shark in U.S. waters.
The Physical and Biological Features of Breeding Habitat That Are
Essential to the Conservation of the Species
Little information exists on the reproductive ecology of the
oceanic whitetip shark, as mating behavior is rarely observed in the
wild and has not been formally documented. Important areas for mating
are also unknown for oceanic whitetip sharks and information regarding
their reproductive periodicity and specific mating seasons is limited.
To identify potential sites as mating grounds, we looked for the
presence of both mature females and males. Aside from one established
aggregation location in foreign waters (Cat Island, Bahamas), which may
be due to availability of food as opposed to reproductive purposes
(Madigan et al. 2015), there are no known aggregation sites of mature
oceanic whitetip sharks. In examining fisheries observer data and
tagging data for revising the EFH designation for the oceanic whitetip
shark (NMFS 2017), high encounters of oceanic whitetip adults have been
observed in pockets along the U.S. East Coast from South Carolina to
Florida in waters greater than 200 m, with potential hotspots off the
eastern central coast of Florida and in the Gulf of Mexico south of
Louisiana and Texas (J. Carlson, NMFS SEFSC, pers. comm. to C. Young,
NMFS OPR, 2019). Based on this limited information, we can cautiously
confirm that male and female adult oceanic whitetip sharks co-occupy
waters under U.S. jurisdiction in the Atlantic and Gulf of Mexico.
Nonetheless, we have no evidence to confirm that these individuals are
mating in these waters, nor can we identify any physical or biological
features that would facilitate successful breeding in these
geographical areas and thus be essential to the conservation of the
species.
In the U.S. western Pacific, including Hawaii, American Samoa,
Guam, and CNMI, EFH for adult and juvenile oceanic whitetip sharks is
broadly defined as the water column down to a depth of 1,000 m from the
shoreline to the outer limit of the EEZ (WPFMC 2009). Thus, similar to
EFH in the Atlantic, EFH in the Pacific is designated the same for all
size classes in this region. It should also be noted that this is a
generic EFH designation for all pelagic species, and not specific to
the oceanic whitetip shark.
A tagging study in Hawaiian waters, conducted from March 2001
through November 2006, involved the capture and tagging of both mature
males and females in the general vicinity that has been identified as a
potential pupping ground (i.e., the area between 150[deg] W and
180[deg] W and just above 10[deg] N; Bonfil et al. 2008). However, only
11 of the 16 tagged sharks were measured and only four were likely
mature (3 males and 1 female), with the remaining likely immature
juveniles. Adults of both sexes have also been caught in the pelagic
longline fishery operating in the Hawaiian EEZ and in the
Papahanaumokuakea Marine National Monument. Based on an assessment of
interactions with the Hawaii pelagic longline fishery from 2004-2018,
adults of both sexes occur in Hawaiian waters, and the majority of
interactions occur on the north side of the Hawaiian Islands in a
linear band stretching southeast to northwest within the limits of the
EEZ, both inside and outside of the Papahanaumokuakea Marine National
Monument (NMFS 2019). One area of high occurrence of interactions is on
the south-westernmost portion of the EEZ, within the limits of the
Monument (NMFS 2019). Adults of both sexes have also been caught off
Kona, Hawaii (M. Hutchinson, NMFS Pacific Islands Fisheries Science
Center, pers. comm. to Chelsey Young, NMFS OPR, 2017). Other analyses
of fisheries catch data from across the Western and Central Pacific
indicate that adults appear to predominate more to the southwest near
the identified center of abundance (10[deg] S, 190[deg] E; refer to
Figure 3 in Clarke 2011) and may overlap with waters of American Samoa.
However, while adults of both sexes likely co-occur in waters under
U.S. jurisdiction in both Hawaii and American Samoa, we have no
additional information to confirm that these areas represent mating
grounds for the species, or identify the physical and biological
features that would be necessary for mating to occur in these areas.
[[Page 12904]]
Overall, the areas where oceanic whitetip shark mating occurs
remain unknown. Additionally, there has not been any systematic
evaluation of the particular physical or biological features that
facilitate successful mating behavior. As such, we cannot identify
physical or biological features of breeding habitat that are essential
to the conservation of the species.
The Physical and Biological Features of Migratory Habitat That Are
Essential to the Conservation of the Species
Although small and large-scale migratory movements have been
observed for the oceanic whitetip shark, information regarding movement
patterns or possible migration paths is fairly limited (Bonfil et al.
2008). During longline fishing surveys in the Central Pacific Ocean,
Strasburg (1958) noted that oceanic whitetip sharks did not exhibit any
specific migratory pattern. Since then, several tagging studies have
been conducted on oceanic whitetip sharks to determine horizontal and
vertical movement patterns of the species, confirming the species'
strong thermal preference for temperatures above 20 [deg]C, highly
migratory nature, and site fidelity to certain locations (Tolotti et
al. 2017; Howey et al. 2016; Tolotti et al. 2015; Howey-Jordan et al.
2013; Carlson and Gulak 2012; Musyl et al. 2011).
In the Atlantic, limited tagging data from the NMFS Cooperative
Tagging Program (Kohler et al. 1998; NMFS unpublished data) from eight
oceanic whitetip sharks do not elucidate any migratory paths or
corridors for the oceanic whitetip shark. The tagging data largely
reveal the movements of some juveniles from the northeastern Gulf of
Mexico to the East Coast of Florida, from the Mid-Atlantic Bight to
southern Cuba, from the Lesser Antilles west into the central Caribbean
Sea, from east to west along the equatorial Atlantic, and from southern
Brazil to farther offshore in a northeasterly direction (Bonfil et al.
2008). Only one adult of unknown sex was both tagged and recaptured
near Cat Island, Bahamas (NMFS unpublished data). In another tagging
study at Cat Island, 11 mature oceanic whitetip sharks (10 females, 1
male) were tagged in May of 2011. After remaining within 500 km of the
tagging site for approximately 30 days, individuals dispersed across a
vast area of the western North Atlantic and to several different
locations, with many of the sharks returning to the Bahamas
approximately 150 days later (Howey-Jordan et al. 2013). However,
unlike other pelagic animals in the North Atlantic that exhibit more
uniform movement patterns within a single demographic group, mature
oceanic whitetip females tagged were not uniform in their movement
patterns in the months after they were tagged (Howey-Jordan et al.
2013). Some individuals remained within the Bahamas' EEZ for their
entire track while others made long-distance movements outside of the
EEZ (Howey-Jordan et al. 2013). This may be attributed to the oceanic
whitetip's presumed biennial reproduction cycle (Backus et al. 1956;
Seki et al. 1998), resulting in differences between individuals in
particular stages of the reproductive cycle; thus, variation in
individual movements may correspond to migrations by gravid and non-
gravid females to disjunct pupping and mating areas (Howey-Jordan et
al. 2013). However, this has yet to be confirmed, and more information
is needed to determine why these sharks are moving to particular
locations (e.g., northern Lesser Antilles, northern Bahamas, and north
of the Windward Passage). Moreover, none of these locations are within
U.S. waters.
In Hawaiian waters, tagging data from 13 oceanic whitetip sharks
revealed a complex pattern, where nine individuals showed a meandering
swimming behavior and three individuals made more straight-line
movements (Musyl et al. 2011). The three individuals that made more
straight-line movements were all males, whereas the sharks that
followed the meandering swimming pattern and remained relatively close
to the tagging area were a mix of both males and females (Musyl et al.
2011). Aside from confirming the epipelagic niche these sharks occupy
and their strong thermal preference of temperatures above 20 [deg]C,
there were no obvious reasons underpinning the movements undertaken by
the tagged individuals.
Although the available information suggests that these sharks do
undergo short and long-distance migrations, the space or migratory
corridor used by oceanic whitetip sharks during these migrations
remains unknown. In addition, the migratory tracking studies that have
been conducted in waters under U.S. jurisdiction have not elucidated
any information on any potential migratory corridors or habitats that
may exist within waters under U.S. jurisdiction for the oceanic
whitetip shark. Until such time that the movements and migrations of
the species throughout its life cycle are better understood, the
importance of physical features (e.g., salinity and temperature) to the
oceanic whitetip shark's distribution cannot be clearly established
(Bass et al. 1973). As such, we cannot identify any specific essential
features that define migratory habitat for oceanic whitetip sharks.
Unoccupied Areas
Section 3(5)(A)(ii) of the ESA defines critical habitat to include
specific areas outside the geographical area occupied by a threatened
or endangered species at the time it is listed if the areas are
determined by the Secretary to be essential for the conservation of the
species. Regulations at 50 CFR 424.12(b)(2) address designation of
unoccupied area as critical habitat and the regulations at 50 CFR
424.12(g) state that critical habitat shall not be designated within
foreign countries or in other areas outside of United States
jurisdiction.
Because we are unable to identify any physical or biological
features of oceanic whitetip shark habitat that are essential to the
conservation of the species, we cannot identify any unoccupied habitat
that contains such features. Furthermore, due to the limited
understanding of habitat use by the oceanic whitetip shark, we cannot
identify any unoccupied areas that have a reasonable certainty of
contributing to the conservation of the species or are essential to the
conservation of the species.
Critical Habitat Determination
Given the best available information and the above analysis of this
information, we find that there are no identifiable occupied areas
under the jurisdiction of the United States that contain physical or
biological features that are essential to the conservation of the
species or unoccupied areas that are essential to the conservation of
the species. Thus, we conclude there are no specific areas within the
oceanic whitetip shark's respective range and under U.S. jurisdiction
that meet the definition of critical habitat; and therefore, we have
determined that a critical habitat designation for oceanic whitetip
sharks is not prudent.
Although we have made this ``not prudent'' determination, the areas
occupied by oceanic whitetip sharks under U.S. jurisdiction will
continue to be subject to conservation actions implemented under
section 7(a)(1) of the ESA, as well as consultations pursuant to
section 7(a)(2) of the ESA for Federal activities that may affect the
oceanic whitetip shark, as determined on the basis of the best
available information at the time of the action. Through the
consultation process, we will continue to assess effects of Federal
actions on the species and its habitat.
[[Page 12905]]
Additionally, we remain committed to promoting the recovery of the
oceanic whitetip shark through both domestic and international efforts.
As noted in the proposed and final rules (81 FR 96304, December 29,
2016; 83 FR 4153, January 30, 2018, respectively), the most significant
threat to the oceanic whitetip shark is overutilization by commercial
fisheries, primarily in areas outside of U.S. jurisdiction. Oceanic
whitetip sharks are caught as bycatch in a number of fisheries
throughout their range, and they are still a prevalent species in the
international fin trade despite retention prohibitions in tuna Regional
Fisheries Management Organizations and a Convention on International
Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix II
listing. Therefore, efforts to address overutilization of the species
through regulatory measures appear inadequate (Young et al. 2017).
Thus, recovery of the oceanic whitetip shark is highly dependent upon
international conservation efforts. To address this, we have developed
a recovery plan outline that provides our preliminary strategy for the
conservation of the oceanic whitetip shark. This outline can be found
on our website at: https://www.fisheries.noaa.gov/species/oceanic-whitetip-shark#resources and provides an interim recovery action plan
as well as preliminary steps we will take towards the development of a
full recovery plan. We also conducted two recovery planning workshops:
One in Honolulu, Hawaii (April 23-24, 2019) that focused on the Indo-
Pacific portion of the species' range, and one in Miami, Florida
(November 13-14, 2019) that focused on the Atlantic/Caribbean portion
of the species' range. These workshops brought together numerous
experts and various stakeholders to collect information, facts, and
perspectives on how to recover the oceanic whitetip shark. Input
received from these workshops, including ideas and recommendations
regarding recovery criteria and actions, will help inform the
development of the forthcoming recovery plan for the species.
We will continue to work towards the conservation and recovery of
oceanic whitetip sharks, both on a domestic and global level, including
with our international partners and within regional fisheries
management organizations and other international bodies to promote the
adoption of conservation and management measures for the threatened
oceanic whitetip shark.
References
A complete list of all references cited herein is available upon
request (see FOR FURTHER INFORMATION CONTACT).
Authority: The authority for this action is the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: February 28, 2020.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
[FR Doc. 2020-04481 Filed 3-4-20; 8:45 am]
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