[Federal Register Volume 80, Number 221 (Tuesday, November 17, 2015)]
[Notices]
[Pages 71774-71784]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-29262]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[Docket No. 150904820-5820-01]
RIN 0648-BF34
Endangered and Threatened Species; Determination on the
Designation of Critical Habitat for Three Scalloped Hammerhead Shark
Distinct Population Segments
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of critical habitat determination.
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SUMMARY: We, NMFS, find that there are no marine areas within the
jurisdiction of the United States that meet the definition of critical
habitat for the Central and Southwest (Central & SW) Atlantic
Distinction Population Segment (DPS), Indo-West Pacific DPS, or Eastern
Pacific DPS of scalloped hammerhead shark. Based on a comprehensive
review of the best available scientific and commercial data for use in
the identification of critical habitat, we find that there are no
identifiable physical or biological features that are essential to the
conservation of these scalloped hammerhead DPSs and found within areas
under U.S. jurisdiction, or any areas outside of the geographical area
occupied by the listed DPSs under U.S. jurisdiction that are considered
essential to their conservation. As such, we find that there are no
specific areas under the jurisdiction of the United States that meet
the definition of critical habitat.
DATES: This finding is made on November 17, 2015.
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 Web site at http://www.fisheries.noaa.gov/pr/species/fish/scalloped-hammerhead-shark.html.
FOR FURTHER INFORMATION CONTACT: Maggie Miller, NMFS, Office of
Protected Resources, (301) 427-8403.
SUPPLEMENTARY INFORMATION:
Background
On July 3, 2014, we published a final rule to list the Central and
Southwest (Central & SW) Atlantic Distinct Population Segment (DPS) and
the Indo-West Pacific DPS of scalloped hammerhead shark (Sphyrna
lewini) as threatened species under the
[[Page 71775]]
Endangered Species Act (ESA), and the Eastern Atlantic DPS and Eastern
Pacific DPS of scalloped hammerhead sharks as endangered species under
the ESA (79 FR 38213). Section 4(b)(6)(C) of the ESA requires the
Secretary of Commerce (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. At the time of listing, we concluded that critical habitat
was not determinable at that time because: (1) Sufficient information
was not currently available to assess impacts of designation; and (2)
sufficient information was not currently available regarding the
physical and biological features essential to conservation. We
announced our intention to consider critical habitat for the Central &
SW Atlantic, Indo-West Pacific, and Eastern Pacific DPSs in a separate
rulemaking, and we requested relevant information from interested
persons to help us: (1) Identify and describe the physical and
biological features essential to the conservation of the scalloped
hammerhead DPSs; and (2) assess the economic consequences of
designating critical habitat for the DPSs. We solicited input from
government agencies, the scientific community, industry and any other
interested party on features and areas that may meet the definition of
critical habitat for the DPSs that occur in U.S. waters or territories,
but we did not receive any response to this solicitation. Subsequently
we researched, reviewed, and compiled the best available scientific and
commercial data available to be used in the identification of critical
habitat for the Central & SW Atlantic, Indo-West Pacific, and Eastern
Pacific DPSs. However, as discussed below, based on these data we find
that there are no identifiable physical or biological features that are
essential to the conservation of the scalloped hammerhead DPSs and
found within areas under U.S. jurisdiction. As such, we find that there
are no marine areas within U.S. jurisdiction that meet the definition
of critical habitat.
This finding describes information on the biology, distribution,
and habitat use of scalloped hammerhead sharks and the methods used to
identify areas that may meet the definition of critical habitat. In
this determination, we focus on those aspects directly relevant to the
designation of critical habitat for scalloped hammerhead sharks. For
more detailed information on the biology and habitat use of scalloped
hammerhead sharks, refer to the status review report (Miller et al.
2014) and the proposed and final listing rules (78 FR 20717, April 5,
2013; 79 FR 38213, July 3, 2014).
Scalloped Hammerhead Shark Biology and Status
The following discussion of the life history and status of the
scalloped hammerhead shark DPSs is based on the best scientific data
available, including the Scalloped Hammerhead Shark Status Review
Report (Miller et al. 2014).
All hammerhead sharks belong to the family Sphyrnidae and are
classified as ground sharks (Order Carcharhiniformes). Most
hammerheads, including the scalloped hammerhead shark, belong to the
Genus Sphyrna. The hammerhead sharks are recognized by their laterally
expanded head that resembles a hammer, hence the common name
``hammerhead.'' The scalloped hammerhead shark (Sphyrna lewini) is
distinguished from other hammerheads by a marked central indentation on
the anterior margin of the head, along with two more indentations on
each side of this central indentation, giving the head a ``scalloped''
appearance.
Scalloped hammerhead sharks can be found in coastal warm temperate
and tropical seas worldwide. They occur over continental and insular
shelves, as well as adjacent deep waters, but are seldom found in
waters cooler than 22[deg] C (Compagno 1984; Schulze-Haugen and Kohler
2003). These sharks range from the intertidal and surface to depths of
up to 450-512 m (Sanches 1991; Klimley 1993), with occasional dives to
even deeper waters (Jorgensen et al., 2009). They have also been
documented entering enclosed bays and estuaries (Compagno 1984).
Both juveniles and adult scalloped hammerhead sharks occur as
solitary individuals, pairs, or in schools. The schooling behavior has
been documented during summer migrations off the coast of South Africa
as well as in permanent resident populations, like those in the East
China Sea (Compagno 1984). Adult aggregations are most common offshore
over seamounts and near islands, whereas neonate and juvenile
aggregations are more common in nearshore nursery habitats (Compagno
1984; Duncan and Holland 2006; CITES 2010; Hearn et al. 2010; Bejarano-
[Aacute]lvarez et al. 2011; Bessudo et al. 2011). It has been suggested
that juveniles inhabit these nursery areas for up to or more than a
year, as they provide valuable refuges from predation (Duncan and
Holland 2006).
The scalloped hammerhead shark is a high trophic level predator
(trophic level = 4.1; Cort[eacute]s 1999) and opportunistic feeder with
a diet that includes a wide variety of teleosts, cephalopods,
crustaceans, and rays (Compagno 1984; Bush 2003; J[uacute]nior et al.
2009; Noriega et al. 2011). In terms of reproduction, the scalloped
hammerhead shark is viviparous (i.e., gives birth to live young), with
a gestation period of 9-12 months (Branstetter 1987; Stevens and Lyle
1989), which may be followed by a one-year resting period (Liu and Chen
1999). Females attain maturity around 200-250 cm total length (TL)
while males reach maturity at smaller sizes (range 128-200 cm TL).
Parturition may be partially seasonal (Harry et al. 2011), with
neonates present year round but with abundance peaking during the
spring and summer months (Duncan and Holland 2006; Adams and Paperno
2007; Bejarano-[Aacute]lvarez et al. 2011; Harry et al. 2011; Noriega
et al. 2011). Females move inshore to birth, with litter sizes anywhere
between 1 and 41 live pups. Observed maximum sizes for male scalloped
hammerheads range from 196-321 cm TL, with the oldest male scalloped
hammerhead estimated at 30.5 years (Piercy et al. 2007). Observed
maximum sizes for female scalloped hammerheads range from 217-346 cm
TL, with the oldest female scalloped hammerhead estimated at 31.5 years
(Kotas et al. 2011).
Based on the genetic diversity among subpopulations, geographic
isolation, and differences in international regulatory mechanisms, we
identified six DPSs of scalloped hammerhead sharks that are both
discrete and significant to the taxon as a whole. The six scalloped
hammerhead shark DPSs, which comprise the global population, are: (1)
Northwest Atlantic and Gulf of Mexico DPS, (2) Central & SW Atlantic
DPS, (3) Eastern Atlantic DPS, (4) Indo-West Pacific DPS, (5) Central
Pacific DPS, and (6) Eastern Pacific DPS. All scalloped hammerhead
sharks are both targeted and taken as bycatch in many global fisheries,
with their fins a primary product for international trade. However, the
exploitation by commercial and artisanal fisheries and lack of adequate
regulatory mechanisms, combined with the species' biological
vulnerability to depletion, has led to declines of the Eastern
Atlantic, Eastern Pacific, Central & SW Atlantic, and Indo-West Pacific
DPSs to the point where the Eastern Atlantic and Eastern Pacific DPSs
are presently in danger of extinction and the Central & SW
[[Page 71776]]
Atlantic and Indo-West Pacific are likely to become so in the
foreseeable future.
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
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 listed scalloped hammerhead shark DPSs: (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
We have interpreted ``geographical area occupied'' in the
definition of critical habitat as the range of the species at the time
of listing (45 FR 13011; February 27, 1980). Further, our regulations
at 50 CFR 424.12(h) state: ``Critical habitat shall not be designated
within foreign countries or in other areas outside of United States
jurisdiction.'' The distribution of the Eastern Atlantic DPS of
scalloped hammerhead shark is found entirely in waters outside of U.S.
jurisdiction. As such, we cannot designate critical habitat for the
Eastern Atlantic DPS and will focus the following discussion on the
other three listed scalloped hammerhead DPSs: Eastern Pacific DPS,
Central & SW Atlantic DPS, and Indo-West Pacific DPS.
Eastern Pacific DPS
The Eastern Pacific DPS generally occurs off the coasts of Mexico
and within the Gulf of California, from 32[deg]N latitude south to
northern Peru, around 4[deg]S latitude. We characterize this
geographical area as the ``core range'' or occupied area of the DPS
(where one would most likely observe scalloped hammerhead sharks). This
core range is entirely outside of U.S. jurisdiction. However,
individuals of the species have been documented north and south of
these core range boundary lines, but rarely and usually only during
specific weather events. These observations primarily occur during
strong El Ni[ntilde]o events, defined as a positive sea surface
temperature (SST) departure from normal greater than or equal to
+1.5[deg]C for 5 consecutive 3-month running mean SSTs, and represent
an opportunistic northward displacement of the species (Siegel 1987;
Shane 2001). It is important to note that these strong El Ni[ntilde]o
events are only identified as such after they have already occurred
(since they are based on 3-month running averages), and, as such, are
difficult to forecast. There is no information that the areas off
southern California and areas north, and off Peru and Chile, are now or
were historically used as habitat for the species. Given the amount of
fishing effort as well as the human population density in these
regions, it is highly unlikely that substantial concentrations of
scalloped hammerhead sharks would have passed unnoticed. As such, we
consider these areas outside of the core range to be used solely by
vagrants (individuals that occur outside of their normal range) and
only during rare weather events that are difficult to forecast. Below
we provide further information on the occupation and use of these areas
to support this conclusion.
In southern California waters (which are under U.S. jurisdiction),
the first verified observation of a scalloped hammerhead shark was in
1977 (Fusaro and Anderson 1980). Since then, observations have been
sporadic and only associated with unusually warm water, as occurs
during El Ni[ntilde]o Southern Oscillation (ENSO) events. Based on the
available information, we found confirmation of 26 scalloped hammerhead
individuals in southern California waters since 1977 (Fusaro and
Anderson 1980; Siegel 1985; Lea and Rosenblatt 2000; Shane 2001;
Galante 2014). The majority of these observations occurred immediately
before, during, and following the strong 1997-1998 ENSO event (Lea and
Rosenblatt 2000; Shane 2001). Between 1997 and 1999, 19 young-of-the-
year (YOY) (<100 cm TL) scalloped hammerhead sharks were caught in San
Diego Bay (Shane 2001). Since 1999, only one scalloped hammerhead shark
has been observed in southern California waters, caught on video by
spear fishermen off Anacapa Island, Channel Islands in October of 2014
(Galante 2014). The observed scalloped hammerhead sharks consist of
adult female and juvenile sharks, suggesting that during strong El
Ni[ntilde]o events, the species may use southern California waters as
pupping and nursery grounds. The last strong (>=1.5[deg]C SST) El
Ni[ntilde]o event to occur was in 1997-1998. Since then, there have
been a number of weak (0.5 to 0.9[deg]C SST anomaly) and moderate (1.0
to 1.4[deg]C SST anomaly) El Ni[ntilde]o events, but based on the
observational data, these events do not appear to transform the
southern California waters into occupiable habitat for the species.
Similarly, in the central-south eastern Pacific, off the coasts of
Peru and Chile, scalloped hammerhead observations are rare and also
seem to be correlated with El Ni[ntilde]o events. A single reference to
the occurrence of the species in waters of Peru points to the presence
of the species off Puerto Pizzaro in 1998, which is located in northern
Peru, very close to the border of Ecuador (Love et al. 2005). As
mentioned previously, 1997-1998 registered as a strong El Ni[ntilde]o
event, bringing much warmer waters to the eastern Pacific, and
especially off the coast of Peru. This could explain the observation of
the species in 1998, as, since then, no other observations of the
species in the waters off Peru have been reported. In a recent paper
that examined shark landings in Peru from 1996-2010, the authors found
no records of scalloped hammerhead sharks (Gonzalez-Pestana et al.
2014).
In Chile, the first record of the species is from 2006 and is based
on the genetic identification of three dried shark fins that were
stored in a commercial warehouse for export to the international market
(Sebastian et al. 2008). It is unclear where these scalloped hammerhead
sharks were caught, but the authors suggest that many of the pelagic
sharks are caught by the artisanal and industrial swordfish fisheries
operating in Chile's exclusive economic zone (EEZ), and by the
nearshore artisanal fisheries operating in north-central Chile. The
sharks are generally landed at Coquimbo (29[deg]579 S, 71[deg]209 W);
however, the authors obtained the three scalloped hammerhead shark fins
from a storage warehouse in the town of Paico, in central Chile. This
remains the only record of the species from Chile. Although the origin
of the scalloped hammerhead sharks is uncertain, there was a weak El
Ni[ntilde]o event that occurred
[[Page 71777]]
at the end of 2006 and could possibly explain the occurrence of these
three sharks in Chilean waters at that time. However, given the
extremely rare occurrence of the species in waters off Peru and Chile,
even during El Ni[ntilde]o events, these areas do not likely contain
habitat for the species.
For the foregoing reasons, we find that the geographical area
occupied by the Eastern Pacific DPS at the time of ESA listing is the
previously-defined core range of the species, which extends over a
broad area of the Eastern Pacific Ocean. Specifically, the geographical
area occupied by the Eastern Pacific DPS includes all coastal and
oceanic waters between 32[deg]N and 4[deg]S latitude, and follows the
boundary lines of the DPS for longitude from 140[deg] W to 150[deg] W.
We find that the geographical areas outside of this delineation where
scalloped hammerhead sharks have been observed (i.e., areas off
California, Peru and Chile) are used solely by vagrant individuals and
only during rare weather events and, as such, are not identified as
geographical areas occupied by the Eastern Pacific DPS at the time of
listing. Given these findings, we conclude that there are no
geographical areas occupied by the Eastern Pacific DPS that are within
the jurisdiction of the United States at the time of listing.
Central & Southwest Atlantic DPS
The geographic range of the Central & SW Atlantic DPS includes all
coastal and oceanic waters from 28[deg] N. latitude to 36[deg] S.
latitude, following the boundary lines designated for this DPS.
Although this range covers the territorial waters of Puerto Rico and
the U.S. Virgin Islands (USVI), as well as the Navassa Island National
Wildlife Refuge, there is little to no available information on the
occurrence or distribution of the scalloped hammerhead shark within
these waters at the time of listing.
Smooth, scalloped, and great hammerhead sharks are noted as
historically occurring in USVI and Puerto Rican waters. In terms of
habitat use around the USVI, personal communication (from E. Kadison,
Ecology Laboratory Specialist, University of the Virgin Islands)
suggests that Magens Bay, St. Thomas, may be a breeding ground for
hammerheads, based on anecdotal reports of large aggregations found in
the bay; however, the species of the hammerheads within Magens Bay was
unknown (E. Kadison, personal communication, 2015). We could find no
other information on the use of Magens Bay by hammerhead sharks that
could help clarify or support the anecdotal reports. Similarly, Salt
River Canyon off St. Croix's north shore was also noted as a diving
spot for seeing the ``occasional'' large hammerhead, but species was
not identified (N2Theblue 2014). The scalloped hammerhead shark is
included in St. Croix's checklist of marine and inland fishes based
only on records of two individuals that were caught as bycatch in 1991
during fishing operations for bigeye scad (Tobias 1991; Smith-Vaniz and
Jelks 2014). We also received a photo of a hammerhead shark from a
researcher conducting a longline shark survey in the area, but upon
inspection identified the shark as a great hammerhead (E. Kadison,
pers. comm. 2015). In fact, the great hammerhead shark is noted as a
``common Caribbean species'' in these waters, often found inshore and
around coral reefs (Smith-Vaniz and Jelks 2014), and thus may likely be
the species observed in the above anecdotal reports.
In waters off Puerto Rico, we found no information on the present
distribution or habitat use of scalloped hammerhead sharks. The only
information indicating the species' historical occurrence in Puerto
Rican waters is its inclusion in a 1974 technical report that provides
the common names of fishes in Puerto Rico (Erdman 1974; revised in
1983). Similarly, the presence and distribution of scalloped hammerhead
sharks in the Navassa Island National Wildlife Refuge are unknown. In
1998, seven scalloped hammerhead sharks were caught in the refuge
during an exploratory longline fish research survey conducted by NMFS
scientists (Grace et al. 2000), indicating its past occurrence in these
waters. A number of more recent NOAA surveys have been conducted in the
Navassa Island National Wildlife Refuge; however, these surveys have
focused on the nearshore reef habitat and fish assemblages and do not
report any observations of scalloped hammerhead sharks (Miller 2003;
Piniak et al. 2006). As such, we have no information on the present
occurrence of the species in the Navassa Island National Wildlife
Refuge.
Based on the foregoing information, we cannot establish if the
geographical area occupied by the listed Central & SW Atlantic DPS
includes any areas under the jurisdiction of the United States.
Although scalloped hammerhead sharks have been included in historical
checklists or observed in fish surveys conducted over 15 years ago, we
have no information to indicate that the species was present in the
territorial waters of Puerto Rico, USVI, or the Navassa Island National
Wildlife Refuge at the time of listing. Because all three species of
hammerhead sharks are noted as occurring in these waters, with the
great hammerhead shark described as ``common,'' we cannot assume that
the anecdotal reports of hammerhead sharks specifically refer to
scalloped hammerhead sharks. As such, we consider the waters under U.S.
jurisdiction within the Central & SW Atlantic DPS range to be
unoccupied areas at the time of listing.
Indo-West Pacific DPS
The geographic range of the Indo-West Pacific DPS includes all
coastal and oceanic waters from 40[deg] N. latitude to 36[deg] S.
latitude, and follows the boundary lines designated for this DPS.
Although this range covers the territorial waters of Guam,
Commonwealth of the Northern Mariana Islands (CNMI), American Samoa,
and the Pacific Remote Island Areas (PRIAs), there is very little
information on the occurrence, distribution, or use of habitat by the
scalloped hammerhead shark within these waters at the time of listing.
Most of the available information is based on personal observations and
anecdotal reports of the species. In Guam, anecdotal reports suggest
that Apra Harbor may have been used as a pupping ground for scalloped
hammerhead sharks, based on the observed presence of young scalloped
hammerhead sharks in Sasa Bay over a decade ago (D. Burdick, Research
Associate, University of Guam, personal communication 2015). Over the
time period of 1982-2004, a NMFS scientist working in Guam indicated
that he personally observed and caught juvenile and adult scalloped
hammerhead sharks in Apra Harbor (specifically the channel that
connects the inner harbor and Sasa Bay) and observed juveniles near
northern Piti, the Pago Bay river mouth, and the Ylig River mouth, and
adults outside of Pago Bay and Tarague Beach (G. Davis, Assistant
Regional Administrator for Habitat Conservation, NMFS, personal
communication 2015). More recent observations, from Dr. Terry Donaldson
(Professor, University of Guam), suggest that adults may periodically
use Apra Harbor. He noted that he has personally observed them, albeit
only very rarely over the past few years, in Apra Harbor and the inner
harbor. The sharks occurred as solitary individuals (not schools), and
he detailed one observation of a large adult feeding on a fish in the
inner harbor. He also noted that neither he nor his technicians have
observed any juveniles in Apra Harbor over the last few years.
In terms of occurrence around the PRIAs, we received personal
communication from NMFS research
[[Page 71778]]
scientists that they have observed and recorded scalloped hammerhead
sharks around the islands as recently as 2012 (I. Williams, Research
Fish Biologist, NMFS; K. Lino, Marine Ecosystems Research Coordinator,
NMFS; personal communication 2014). Since 2000, NMFS scientists have
conducted tow diver surveys every 3 years at the PRIAs, during which
they are at each island for 3-5 days surveying the reef. The survey
method consists of two divers pulled behind a vessel surveying for
large fish (>50 cm TL) and also looking at the benthic habitat of the
islands' fore reefs from 30-60 feet (9.1 m-18.3 m) depths. According to
their observations and records, schools of adult scalloped hammerhead
sharks are most commonly observed at Jarvis and Baker Islands, although
adult individuals tend to be observed daily at many of the islands
during the survey period. No juveniles have been recorded during these
surveys.
In addition, these NMFS scientists, who survey at more than 50
U.S.-affiliated islands, atolls, and reefs, have never recorded
scalloped hammerheads in American Samoa, Guam, or CNMI while conducting
these reef surveys. Corroborating these observations, fishery observer
data from 2006-2010 indicate that scalloped hammerhead sharks are also
rarely observed caught in the American Samoa longline fishery, which
primarily operates within the U.S. EEZ around American Samoa (Simmonds
2014). We could find no information on the present occurrence or
distribution of scalloped hammerhead sharks around CNMI.
The above information gives us confirmation of the past and perhaps
present occurrence of the species in U.S. waters within the range of
the Indo-West Pacific DPS. Specifically, at the time of listing, the
geographical areas occupied by the Indo-Pacific DPS likely include
waters off Guam and the PRIAs. Although observations of scalloped
hammerhead sharks in American Samoa waters are rare, they still occur
and, thus, we cannot rule out that habitats in these waters were being
used, at least periodically, at the time of listing. However, given the
severe lack of information about or observations of scalloped
hammerhead sharks within waters of CNMI, we cannot conclude that this
area was occupied by the species at the time of listing.
Conclusion
Based on the information above, we consider the geographical area
occupied by Indo-West Pacific DPS of the scalloped hammerhead shark at
the time of listing to include the waters under U.S. jurisdiction off
Guam, the PRIAs, and American Samoa, and we consider the geographical
areas occupied by the Eastern Pacific and Central & SW Atlantic DPSs at
the time of listing to not include any waters under U.S. jurisdiction.
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 on which are found those physical or biological features
essential to the conservation of the species (hereafter also referred
to as ``essential features'') and that may require special management
considerations or protection. 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.'' Further, our regulations at 50 CFR 424.12(b) for
designating critical habitat state that physical and biological
features that are essential to the conservation of a given species and
that may require special management considerations or protection may
include: (1) Space for individual and population growth, and for normal
behavior; (2) food, water, air, light, minerals, or other nutritional
or physiological requirements; (3) cover or shelter; (4) sites for
breeding, reproduction, rearing of offspring, germination, or seed
dispersal; and generally, (5) habitats that are protected from
disturbance or are representative of the historic geographical and
ecological distributions of a species.
For scalloped hammerhead shark DPSs, we define conservation as the
use of all methods and procedures necessary to bring scalloped
hammerhead sharks to the point at which factors related to population
ecology and vital rates indicate that the population 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 scalloped
hammerhead 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) Feeding, (2) pupping,
(3) migration, and (4) breeding. 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.
The Physical and Biological Features of Foraging Habitat That Are
Essential to the Conservation of the Species
Scalloped hammerhead sharks are opportunistic predators, with a
high degree of trophic plasticity (Torres-Rojas et al. 2006; Rojas et
al. 2014). They feed on a wide range of teleosts, crustaceans, and
cephalopods (Klimley 1987; Torres-Rojas et al. 2006; Junior et al.
2009; Hussey et al. 2011). As juveniles, when they occur primarily in
inshore and shallow coastal waters, their diet is a reflection of their
habitat and consists of small reef fish and crustaceans. For example,
in K[amacr]ne'ohe Bay, a coastal bay of Hawaii consisting of a shallow
reef, YOY scalloped hammered sharks (47-84 cm TL) were observed feeding
mainly on scarids and gobioids abundant around the reef (Clarke 1971).
The species of gobioids were characterized as ``rather ubiquitous and
found in a variety of habitats in the bay'' (Clarke 1971). For those
YOY that were captured in a part of the bay characterized by dead and
silted reefs and an absence of reef fish, stomach analysis showed that
these sharks primarily foraged on crustaceans (principally alpheids),
suggesting the species, even at a young age, is not limited in its
foraging habits but rather adapts to its present habitat and feeds on
whatever prey is available (Clarke 1971). Similarly, in an analysis of
stomach contents from 556 juvenile S. lewini, ranging from 48-160 cm
TL, Torres-Rojas et al. (2006) identified 87 prey species and concluded
that S. lewini is a generalist, un-selective feeder, with the type and
amount of prey consumed by the juvenile sharks primarily determined by
abundance and availability.
The species is also thought to undergo an ontogenetic change in
feeding habits. This change is estimated to occur when the species
reaches sizes of around 100 cm TL (Klimley 1987; Torres-Rojas et al.
2006; Kotas et al. 2012; Rojas et al. 2014). Generally, as the sharks
become
[[Page 71779]]
larger, they begin to venture into neighboring deep-water habitats to
feed on the larger pelagic fishes and squid. In their analysis, Torres-
Rojas et al. (2006) noted that scalloped hammerhead sharks <100 cm TL
in the southern Gulf of California, Mexico, fed primarily on
Loliolopsis diomedaea (46.7 percent Index of Relative Importance (IRI)
in diet), a squid found in shallow waters, whereas sharks >100 cm TL
had a diet consisting more of carangid fishes (30.6 percent IRI) and
Abraliopsis affinis (33.9 percent IRI), a squid more commonly found in
mid-depths and over continental shelves. Female scalloped hammerhead
sharks are thought to undergo this ontogenetic shift in feeding habits
at a smaller size than males, transitioning from juvenile foraging
grounds in shallow, nearshore waters to foraging in pelagic, deeper
water habitat. As Klimley (1987) observed in the Gulf of California,
Mexico, females <=160 cm TL had a higher percentage of pelagic prey and
much lower percentage of benthic prey in their diet compared to males
of similar sizes, consistent with this type of foraging behavior. Off
the coast of South Africa, Hussey (2011) observed that the diet
signatures for female sharks of 161-214 cm TL indicated prolonged
residence in offshore-pelagic waters (as opposed to continental shelf
habitats). The diet signatures of males and females became similar only
after male size increased to >214 cm TL. These findings also seem to
corroborate those from a detailed tracking study of a juvenile female
that was initially tagged in a nearshore nursery ground (La Paz Bay,
Mexico) (Hoyos-Padilla et al. 2014). The female was 95 cm TL when
tagged and spent the next 8 months primarily in shallow waters (<50 m
depths), close to shore and near the surface (Hoyos-Padilla et al.
2014). However, towards the end of the 10-month study period, the shark
was tracked making an increasing number of deeper dives, between 150 to
250 m depths, indicating a transition to offshore waters (Hoyos-Padilla
et al. 2014). At the point of recapture, 10 months later, the shark had
attained a size of 123 cm TL, which appears to fall within the
estimated sizes above which juvenile females begin their ontogenetic
migration (Klimley 1987; Torres-Rojas et al. 2006; Kotas et al. 2012;
Rojas et al. 2014). Klimley (1987) suggests that this offshore
migration occurs sooner for females, enabling them to achieve faster
growth to reproductively-active sizes through access to a greater
abundance of prey. This, in turn, translates to females achieving
maturity at similar ages as their male counterparts (Klimely 1987).
Although little is known regarding the foraging behavior of adults,
based on tracking and diet studies, it is thought that adults (and sub-
adult females that have already migrated offshore) tend to exhibit a
diel feeding pattern (Ketchum et al. 2014a, 2014b). During the day,
sharks are observed refuging in large aggregations in shallow,
nearshore coastal areas, off islands, and over seamount ridges (Klimley
1985; Ketchum et al. 2014a, 2014b). They tend to stay in a small core
area, making occasional vertical dives through the mixed layer, and
generally remaining above the thermocline in waters >23 [deg]C (Bessudo
et al. 2011; Ketchum et al. 2014a). These ``refuge'' areas tend to be
located on the up-current side of islands and also correspond to where
the pelagic assemblage is richer and represents lower-level trophic
groups (such as trevally, pompano, and jacks) (Hearn et al. 2010;
Bessudo et al. 2011; Ketchum et al. 2014a; 2014b; K. Lino, pers. comm.
2014). One theory is that this specific location on the island/
seamounts, where the current splits to flow around obstacles, may cause
an area of entrainment, providing the hammerheads with a food source
upstream of the island (Hearn et al. 2010). Another theory is that the
interactions between abrupt, sloping topography of seamounts and other
bathymetrical features, and the impact of currents, tides, and internal
waves, may enhance fluxes of near-bottom food particles, increasing
abundance of benthic suspension feeders and further supporting higher
densities of resident fish above seamounts (Mohn and Beckmann 2002;
Hearn et al. 2010). However, feeding has not been observed at these
refuge spots. Instead, it is thought that scalloped hammerheads may
aggregate at these locations to reduce energy costs (these refuge spots
are still areas of reduced currents relative to offshore) at areas that
may provide some degree of food availability (with food-rich
thermocline waters preferentially delivered to the up-current side of
the island) and other benefits (such as cleaning stations), but that
work more as a central and vantage location for foraging excursions
into open waters (Ketchum et al. 2014a, 2014b). Based on tracking data,
it is thought that individuals leave the adult aggregations at night to
forage as solitary individuals in the neighboring deep-water pelagic
habitats (Klimley and Nelson 1984, Klimley 1987, Klimley et al. 1988).
Diet analysis shows that cephalopods, in particular, constitute an
important prey item for adult scalloped hammerhead sharks. Deep-water
squid species recorded in the stomachs of scalloped hammerhead sharks
include: Ancistrocheirus lesueuri (Orbigny), Mastigoteuthis sp.,
Moroteuthis robustus (Verrill), Dosidicus gigas (Orbigny) (Klimley,
1987), Histioteuthis sp., Ommastrephes bartramii and Cranchiidae
(Junior et al. 2009). Many of these cephalopod species have a wide
geographic distribution, moving throughout the deep waters of the
ocean, and, as such, it would be difficult to link these prey species
to any ``specific'' areas within the oceanic geographic areas occupied
by the scalloped hammerhead DPSs.
Overall, the best available information indicates that scalloped
hammerhead sharks are opportunistic feeders. The species, regardless of
life stage, does not appear to be limited by foraging grounds, adapting
to its present habitat by feeding on whatever prey are 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. While the above information suggests that
scalloped hammerhead sharks may aggregate in tropical waters, near
seamount ridges or productive coastal areas that face the impinging
current, these areas are thought to be used more for refuging purposes
as opposed to foraging habitats. Although these refuging habitats may
be linked to foraging activities, this is purely speculative.
Additionally, the particular physical or biological features of these
refuging habitats that make them preferential for scalloped hammerhead
aggregations are uncertain and their importance to the life-history
needs of scalloped hammerhead sharks is unknown. Furthermore, no
scalloped hammerhead sharks of the Central & SW Atlantic DPS or Eastern
Pacific DPS have been observed refuging or foraging in the geographic
areas under U.S. jurisdiction. The same holds true for the Indo-West
Pacific DPS, with the exception of a single, personal observation of an
adult scalloped hammerhead shark feeding on a large mullet in the Inner
Harbor of Guam (T. Donaldson, pers. comm. 2014). For the foregoing
reasons, it is not possible to identify any physical or biological
features related to foraging that are essential to the conservation of
the
[[Page 71780]]
species, nor are there any ``specific areas'' that appear to be used
for foraging purposes within waters under U.S. jurisdiction.
The Physical and Biological Features of Pupping Habitat That are
Essential to the Conservation of the Species
Scalloped hammerhead sharks are known to give birth in warm
tropical and temperate shallow, inshore waters. The specific nursery
habitat requisites for such factors as temperature, depth, and
substrate, are highly variable. Below is a summary of the information
on the habitat characteristics of known scalloped hammerhead nursery
areas, identified as such based on the: (1) Common presence of
neonates, YOY, and juvenile scalloped hammerhead sharks in the area,
(2) long residency period of immature individuals in these areas (e.g.,
weeks, months, years), and (3) repeated usage of the area over the
years by these age classes (Salmon-Aguilar et al. 2009).
Nursery habitats for scalloped hammerhead sharks are generally
identified as shallow inshore areas, including bays and estuaries.
K[amacr]ne'ohe Bay in Hawaii, for example, is a well-studied and
confirmed nursery ground for scalloped hammerhead sharks (and is part
of the range of the identified Central Pacific DPS, for which we
determined listing was ``not warranted''; 78 FR 20717, April 5, 2013).
K[amacr]ne'ohe Bay is the largest bay in the Hawaiian Islands (61
km\2\), located on the windward side of Oahu, and is separated from the
ocean by a large barrier reef (0-3 m deep) (Clarke 1971). There are
also two channels that provide access to the ocean on either side of
the bay, the North Channel (10 m deep) and the shallower Sampan Channel
(3 m deep). Most of the bay is around 14 m deep, with the deepest spots
at around 19 m. It has a muddy/silty bottom with temperatures ranging
from 20-30 [deg]C. Patch reefs and small islands are interspersed
throughout the bay. As mentioned above, the scalloped hammerhead
population within this bay has been studied for many years (Clarke
1971; Holland et al. 1993; Duncan and Holland 2006). The juveniles show
a preference for the southern end of the bay, which is characterized as
being more turbid and estuarine than the other parts of the bay. In
fact, females tend to drop the pups in the bay at the start of the
trade-wind season, which stirs up the bay and creates constantly turbid
waters, allowing the juveniles to remain in the bay for a significant
portion of the year (Clarke 1971). The preference for the turbid
portions of the bay is thought to be a defense mechanism, protecting
juveniles from predator visibility. Behavioral observations in this
nursery habitat show that juveniles tend to refuge in aggregations
during the day near the bottom (between 0.5 m and 1.5 m off the bay
floor) and in deeper areas of the bay (Holland et al. 1993). At night,
juveniles tend to disperse, possibly hunting where patch and fringing
reef walls meet the bay floor (Holland et al. 1993).
Identified nursery habitats in other regions also appear to share
many of the same characteristics as those physical and biological
features of K[amacr]ne'ohe Bay. For example, off the east coast of
Australia, along the tropical northern Queensland coastline, there are
a number of primarily shallow (<15 m) bays within which YOY scalloped
hammerhead sharks of the Indo-West Pacific DPS have been observed
(Simpfendorfer et al. 2014). These bays are protected seaward by the
Great Barrier Reef and are also characterized by substrate that is
dominated by silt and mudflats or mangrove-lined foreshores. The bays
themselves tend to vary in other factors, such as freshwater input and
seagrass abundance (Simpfendorfer et al. 2014). Young-of-the-year
scalloped hammerheads have been observed in many of these bays
(including Moreton, Rockhingham, Halifax, Cleveland, Bowling Green,
Upstart, Repulse), but their spatial distribution indicates a
preference for some (e.g., Rockingham, Cleveland, Repulse) more than
others (Simpfendorfer and Millward 1993; Taylor 2008; Simpfendorfer et
al. 2014; Australia Department of Environment 2014). The specific
aspects of these bays that make them more preferential as nursery
habitats over the others is not clear; although, based on information
from Simpfendorfer et al. (2014), these bays receive a greater input of
freshwater compared to some of the bays where scalloped hammerheads
have not been observed. In Cleveland Bay, for example, freshwater flows
from four creeks into the mangrove-dominated southern portion of the
bay, causing significant drops in salinity in the summer (from 39% to
36%) (Kinney et al. 2011). This is also the part of the bay where large
numbers of YOY scalloped hammerheads have been recorded throughout the
year in depths <5 m (Simpfendorfer and Milward 1993). Other physical
aspects of the bay include silty substrates with mangrove-lined
shorelines, areas of coastal reefs, and warm temperatures (SST ranges
from 22.5 [deg]C in winter to 30.5 [deg]C in the summer) (Kinney et al.
2011). In the intertidal surf zone of Cleveland Bay, which is
characterized by mud and sand flats, neonates of S. lewini have also
been caught, but this is a brief occurrence (Tobin et al. 2014). They
appear to only be present during the summer, from October to January,
in depths typically <0.5 m, and thus are assumed to utilize this area
as either transient short-term protection from predators after birth or
possibly for prey resources (shrimp, small fishes), after which the
neonates disperse into the adjoining subtidal nursery area of Cleveland
Bay (Tobin et al. 2014). This migration may explain why more S. lewini
YOY were observed in the southern portion of the Bay from February to
July (Simpfendorfer and Milward 1993).
Apra Harbor, Guam, may also contain nursery habitat for the Indo-
West Pacific DPS of scalloped hammerhead sharks, but this supposition
is based only on anecdotal observations of juvenile sharks in Sasa Bay
and both adults and juveniles in the channel connecting the inner Apra
Harbor and Sasa Bay (personal communication, G. Davis and D. Burdick
2015). Sasa Bay, which is a no-take marine reserve, is a shallow bay
(0-11 m) that primarily consists of sand/mud substrate, with patch
reefs in deeper water and a mangrove swamp that extends along the
coastline. The inner Apra Harbor has been extensively modified through
dredging, construction activities, and landfills undertaken by the U.S.
Navy since 1945 (Smith et al. 2009). The inner Apra Harbor now consists
of a mud bottom of uniform depth, high turbidity, and an abundance of
planktonic and benthic suspension feeders (compared to other parts of
the harbor) but also has a relatively untouched mangrove area at the
mouth of the Atantano River. Depths in the inner Apra Harbor range from
0-11 m, with some deeper areas of 11-18 m (Smith et al. 2009). On the
opposite side of the island, the Pago Bay river mouth has also been
identified as an area where juvenile scalloped hammerhead sharks have
been observed. This area consists of a fringing reef flat, shallow
depths (<10 m) and temperatures that range from around 16 to 34 [deg]C
(Tsuda 2004). Further information about the habitat use of scalloped
hammerhead sharks that could provide insight into the specific physical
or biological features within these systems that support the life-needs
of the species is unknown, with the only available information from
general personal observations and interactions with the species.
Off South Africa, nursery habitats for the Indo-West Pacific DPS
have been identified on the continental shelf off
[[Page 71781]]
the geopolitical provinces that encompass KwaZulu-Natal (KZN) and
northern Eastern Cape. This area is characterized by a narrow
continental shelf and steep continental slope bordered at its eastern
edge by the warm south-westward flowing Agulhas Current (Hussey et al.
2009). In Tugela Bank, KZN, YOY scalloped hammerheads were caught on
trawling grounds in <50 m depths, where temperatures range from 21-27
[deg]C. This area also coincides with the deepest deposit of mud
originating from the discharges of numerous rivers in the area, and, as
a result, the water is permanently turbid (Fennessy 1994). Young-of-
the-year scalloped hammerheads were also caught year-round in the
Transkei area where temperatures range from 16.5-22 [deg]C (the coastal
area just south of KZN), particularly the Port St Johns region which is
the location of the mouth of the Mzimvbu River (Diemer et al. 2011).
These temperatures and depths appear to be a bit cooler and deeper,
respectively, than those described previously for nursery habitats in
this DPS' range.
In the range of the Eastern Pacific DPS, Zanella et al. (2009)
noted significant catches of juvenile scalloped hammerhead sharks in
the vicinity of the mouth of the Tarcoles River, Costa Rica. Within
this area, YOY sharks primarily occurred in depths between 1 and 30 m,
whereas larger juveniles occurred in deeper areas of 61-90 m. Most
sharks were caught in the portion of the river mouth characterized by
muddy substrate, and shallow and murky waters. This area, in
particular, is characterized by higher sedimentation and nutrient flow
due to the influence of a mangrove ecosystem surrounding the coast and
river discharge from the Tarcoles River (Zanella et al. 2009).
Other sites in the Eastern Pacific DPS range that have been
identified as nursery areas are located in the Gulf of California and
further south off the Pacific coast of Mexico. Sites in the Gulf of
California include coastal waters off Mazatlan (Sinaloa) and San
Francisquito and El Barril (Baja California). In the eastern Gulf of
California, features of the areas where large numbers of YOY and
juvenile S. lewini have been observed include both shallow and wide
continental shelves (5-25 km), warm water temperatures, and highly
productive waters. In 2014, Hoyos-Padilla et al. tracked an older
juvenile female scalloped hammerhead shark in the Gulf of California
(tagged in La Paz Bay) and found that the shark generally remained in
depths less than 50 m, with a preference for temperatures of 23-26
[deg]C. The onset of the birthing and nursery period in this area
appears to be governed by temperature, when the temperatures increase
from 18-19 [deg]C in the spring to 30-31 [deg]C in the summer.
Significant upwelling events occur in the central and southern Gulf of
California in winter and spring, generating high productivity and
greater food availability during the peak breeding months and likely
contribute to this area's importance as a nursery habitat for scalloped
hammerhead sharks (Torres et al. 2008).
The Gulf of Tehuantepec, off the southern coast of Mexico, is also
thought to be an important spawning and nursery area for S. lewini
based on the presence of YOY, juveniles, and pregnant females in these
waters. It is characterized by a narrow continental shelf with rivers
and temporal streams that form large coastal lagoons and estuaries, and
well-developed mangrove forest communities that provide abundant food
resources (Alego-plata et al. 2007; Rios-Jara et al. 2009).The region
has a tropical warm sub-humid climate with an average annual
temperature close to 26 [deg]C (range 14-31 [deg]C at 10 m depths;
Tapia-Garcia et al. 2007). It also experiences numerous summer rains
(annual rainfall = 2500-3000[thinsp]mm), making this region one of the
wettest of Mexico (Rios-Jara et al. 2009). It is during the wet season
that observations of YOY and juveniles increase, with birthing thought
to occur in July and August. From October to May, this region
experiences the strong ``Tehauntepec winds'' that cause the collapse of
the thermocline and create upwelling of nutrients (Tapia-Garcia et al.
2007), likely providing a source of greater food availability during
the first years of growth for these juvenile sharks.
From the best available information, the physical features of
nursery areas in the Atlantic appear to be generally similar to those
found in the Pacific. In the range of the Central & SW Atlantic DPS,
Kotas et al. (2012) noted that in waters off Brazil pups tend to occur
in shallow, coastal, turbid areas, in depths <20 m with sandy
substrate. Juveniles are found near bays, estuaries, and over
continental shelf in depths up to around 275 m (Kotas et al. 2012). No
other information on nursery habitat characteristics for this DPS,
especially those physical and biological features that directly support
the life-history needs of the species, could be found. In fact, with
the exception of the anecdotal information from Guam waters, there are
no identified nursery grounds within waters under U.S. jurisdiction for
either the Central & SW Atlantic DPS or the Indo-West Pacific DPS. The
same is true for the Eastern Pacific DPS. Although YOY scalloped
hammerhead sharks have been observed in U.S. waters off southern
California, these individuals are identified as vagrants, with their
occurrence associated only with rare strong ENSO events (Lea and
Rosenblatt 2000; Shane 2001). In other words, the presence of YOY
scalloped hammerhead sharks in California waters is not common, nor
have scalloped hammerhead sharks displayed a repeated usage of these
areas over the years. As such, we do not consider U.S. waters off
southern California to contain identified nursery habitat for the
Eastern Pacific DPS.
Based on the foregoing information regarding known or presumed
pupping areas for scalloped hammerhead sharks, the general physical
oceanographic features that appear to be associated with this habitat
include: (1) Relatively shallow inshore bays/estuaries with areas of
moderate to high freshwater input; (2) tropical water temperatures
(>=20 [deg]C); (3) muddy/silty/sandy substrate bottom; (4) presence of
patchy reefs, mangrove systems, or seagrass beds; and (5) areas within
inshore habitats of higher turbidity/current flow. However, because of
the variability in the presence of the above physical features in the
different identified nursery areas (e.g., mud versus silt or sand, low
temperatures (16-22 [deg]C) versus higher temperatures (>30 [deg]C),
varying levels of salinity and freshwater input, shallow depths (<10 m)
versus areas with deeper waters (up to 275m)) we can only characterize
nursery grounds using broad terms to describe the physical features.
Given this level of resolution, and the fact that these features vary
even for nursery grounds within a DPS' range, it is unclear which of
the above physical characteristics, if any, are necessary to facilitate
successful pupping behavior. In other words, we cannot identify whether
any or a combination of these characteristics of nursery grounds are
essential for the conservation of the species. Although scalloped
hammerhead sharks may prefer areas that contain these characteristics,
the available information does not allow us to identify any physical or
biological features within these areas that are essential to support
the life-history needs of scalloped hammerhead sharks. Additionally,
while the available data suggest nursery habitats share many of the
above physical characteristics, these general features are relatively
ubiquitous throughout the global range of the species and not all areas
with the
[[Page 71782]]
above features provide meaningful pupping or nursery habitat.
Furthermore, there is no evidence of scalloped hammerhead sharks being
limited to a specific nursery ground. In fact, Duncan et al.(2006)
provided mtDNA data that argued against strong natal homing behavior by
the species and anecdotal information of scalloped hammerhead sharks
using artificially enlarged estuaries in Hawaii as nursery grounds
(which were 100-600 km from confirmed nursery habitats). In other
words, the species is highly migratory and does not appear to be
limited to certain nursery areas.
As mentioned previously, for the listed DPSs, there are no
confirmed nursery grounds for the species in U.S. waters. Due to the
rarity of the presence of the Central & SW Atlantic DPS in waters under
U.S. jurisdiction, both historically and presently, these waters do not
likely provide important pupping habitat. Similarly, the waters under
U.S. jurisdiction in the Eastern Pacific are considered unoccupied
areas used solely by vagrants of the Eastern Pacific DPS and only
during rare weather events. As such, these waters do not provide
important nursery habitat for the DPS. The anecdotal observations from
Guam lend support to the potential use of waters under U.S.
jurisdiction by juvenile scalloped hammerhead sharks; however, without
knowledge of the essential features that create meaningful pupping
grounds, we cannot identify any areas that meet the definition of
critical habitat. Simply the observation of the presence of juveniles
utilizing these waters (with unknown abundance, duration, habitat use,
or frequency of occurrence) is not enough information to indicate that
these areas contain physical and biological features that are essential
to the conservation of the species. Additionally, the waters under U.S.
jurisdiction for the Indo-West Pacific DPS represent an extremely small
percentage of the suitable habitat available for the DPS (which
comprises the waters of the entire Indian Ocean and Western Pacific
Ocean), and based on the absence of any recent observations of juvenile
scalloped hammerhead sharks utilizing waters off Guam, these waters
under U.S. jurisdiction do not appear to contain important nursery
habitat that could be characterized as essential for the conservation
of the DPS.
The Physical and Biological Features of Migratory Habitat That Are
Essential to the Conservation of the Species
Both small and large-scale migratory movements are a necessary
component in the life-history of the scalloped hammerhead shark.
Examples of small scale migratory movements (<300 km) include those
undertaken for feeding and refuging (Ketchum et al. 2014b; Diemer et
al. 2011; Hearn et al. 2010; Klimley and Nelson 1984). Large scale
migrations have also been observed by scalloped hammerhead sharks and
are thought to occur for foraging but also reproductive purposes
(Ketchum et al. 2014b; Bessudo et al. 2011). Pregnant females must make
large scale migrations from their offshore habitats to coastal inshore
nursery habitats for successful reproduction. Similarly, juvenile
females are also thought to make this migration in the opposite
direction as they attain larger sizes (>100 cm TL). The extent of
juvenile and adult male migrations is unknown, but as some have been
observed in schools offshore (Klimley 1985; Ketchum et al. 2014) and
some in nearshore nursery areas (Clarke 1971; Dudley and Simpfendorfer
2006), it is likely that a proportion of the male population may also
undergo larger scale migrations. For logistical reasons, survey efforts
have been focused in nearshore habitats, with a number of studies
conducted around the island chains in the Eastern Tropical Pacific
(Galapagos, Cocos Island, and Malpelo Island), part of the Eastern
Pacific DPS range. For example, in the Galapagos, Ketchum et al.
(2014b) tagged 134 scalloped hammerhead sharks, 80 percent of which
were females. The most common movement exhibited by these sharks was
short back and forth inter-island movement (<50 km), which was thought
to represent focused foraging movements. However, five tagged scalloped
hammerhead sharks were also tracked making long-distance migrations
(>300 km) across the eastern Pacific, primarily during the warm season
(March to May). One female (possibly mature with a size of 170 cm TL)
was tracked moving from Wolf Island (Galapagos) to Cocos Island off
Costa Rica, a distance of around 700 km. Two other female sharks (both
likely mature, 200 cm TL) were tracked migrating from Darwin Island
(Galapagos) to Cocos Island, a distance of 679 km. One of the females
even returned to Darwin Island, indicating that these long distance
migrations may be directed movements. Similarly, a female tagged at
Malpelo Island (off Colombia) was tracked migrating to Cocos Island and
then to Wolf and Darwin Islands. Results from another tagging study of
scalloped hammerheads around Malpelo Island found many pregnant females
leaving the island around March-April (Bessudo et al. 2011). As pupping
tends to occur in the summer months off the continental Eastern Pacific
(Torres et al. 2008; Rios-Jara et al. 2009; Zanella et al. 2009), it is
thought that these long distance and seemingly directed movements
across the Eastern Pacific may be conducted by female sharks during the
final stages of the gestation period, with the sharks likely migrating
to the continental coast for parturition (Bessudo et al. 2011; Ketchum
et al. 2014b). Additionally, in the Ketchum et al. (2014b) study, one
mature male scalloped hammerhead shark (218 cm TL) was also tracked
making a long-distance migration. The shark travelled from Darwin
Island to Malpelo Island (a distance of 627km) (Ketchum et al. 2014b).
Given that this migration occurred during the same season as the female
long-distance migrations, it could be that a small proportion of the
mature male population may also undergo long-distance migrations,
following reproductively active females to coastal nursery habitats for
mating purposes.
Although the available information suggests that these sharks do
undergo short and long-distance migrations, the space or migratory
corridor used by scalloped hammerhead sharks during these migrations
remains unknown. In addition, we are not aware of any migratory
tracking studies that have been conducted in waters under U.S.
jurisdiction and, therefore, have no information on any potential
migratory corridors that may exist within waters under U.S.
jurisdiction for the listed scalloped hammerhead DPSs. Based on the
foregoing information, we cannot identify any specific essential
features that define migratory habitat for scalloped hammerhead sharks.
The Physical and Biological Features of Breeding Habitat That Are
Essential to the Conservation of the Species
Important areas for mating are largely unknown for scalloped
hammerhead sharks. To identify potential sites as mating grounds, we
looked for the presence of both mature females and males. For the most
part, adult females are usually found schooling offshore with subadult
females (Klimley 1985; Ketchum et al. 2014b). Studies have documented
that these schools also consist of a few adult males (Klimley 1985;
Ketchum et al. 2014a, 2014b). As such, potential mating events may
occur in these offshore refuging schools, but this has not been
confirmed. Furthermore, none of these refuging schools described above
have been observed in waters under U.S. jurisdiction for the listed
scalloped hammerhead DPSs.
[[Page 71783]]
Additionally, adult females, including ones that have recently
given birth, are occasionally observed in identified nursery habitats
along with adult males (Clark 1971; Dudley and Simpfendorfer 2006;
Hussey et al. 2011). It is thought that mating may also occur during
the principal pupping season, and potentially near these nursery areas
(possibly over continental shelf or even near shelf slope; Kotas et al.
2012), with adult females moving inshore for a short time to mate and
then proceeding to migrate offshore (Clarke 1971). Adult males,
however, tend to be observed in larger numbers (sometimes with no
evidence of mature females) staying in these inshore areas for longer
periods of time, perhaps as a way to maximize the number of breeding
females they can encounter (Clarke 1971; Dudley and Simpfendorfer 2006;
Hussey et al. 2011; Yates et al. 2015). However, as stated above, the
areas where scalloped hammerhead shark mating occurs remain unknown and
purely speculative. There has not been any systematic evaluation of the
particular physical or biological features that facilitate or are
necessary for mating to occur. As such, we cannot identify physical or
biological features of breeding habitat that are essential to the
conservation of the species.
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(e) specify that we shall
designate as critical habitat areas outside the geographical area
presently occupied by a species only when a designation limited to its
present range would be inadequate to ensure the conservation of the
species. Our regulations at 50 CFR 424.12(h) also state: ``Critical
habitat shall not be designated within foreign countries or in other
areas outside of United States jurisdiction.''
As discussed previously, the waters off California are not
considered part of the geographical area occupied by the Eastern
Pacific DPS at the time of listing. We also conclude that it is not an
unoccupied area essential to the DPS' conservation, given the rare,
errant use of the area by vagrant scalloped hammerhead sharks in the
past, with this use associated only with sporadic weather events, and
the fact that we have no information to suggest the area is essential
to the conservation of the DPS. Furthermore, for the areas under U.S.
jurisdiction off USVI, Puerto Rico, Navassa Wildlife Refuge, and CNMI,
which we could not conclude were occupied by the applicable scalloped
hammerhead DPSs at the time of listing, we found no information that
would indicate these areas are essential for the conservation of the
listed DPSs. Scalloped hammerhead sharks are highly migratory, and
although they may have historically been observed in these waters, the
lack of historical or anecdotal data or information tends to suggest
these may have been rare or sporadic occurrences as the shark passed
through these waters. We do not find that these unoccupied areas under
U.S. jurisdiction, which additionally comprise such small portions of
the overall ranges of the listed DPSs, are essential to the
conservation of the listed DPSs. As such, we find that there are no
identifiable areas outside the geographical areas occupied by the
listed DPSs that would meet the definition of critical habitat for the
scalloped hammerhead shark DPSs.
Any conservation actions for the listed scalloped hammerhead shark
DPSs that would bring these DPSs to the point that the measures of the
ESA are no longer necessary will need to be implemented by foreign
nations. As noted in the final rule (79 FR 38213, July 3, 2014), the
significant operative threats to the listed scalloped hammerhead DPSs
are overutilization by foreign industrial, commercial, and artisanal
fisheries and inadequate regulatory mechanisms in foreign nations to
protect these sharks from the heavy fishing pressure and related
mortality, with illegal fishing identified as a significant problem in
areas outside of U.S. jurisdiction. Thus, recovery of the listed DPSs
is highly dependent upon international conservation efforts. This
includes increased protection for the listed DPSs from fishery-related
mortality, especially within those foreign areas described above where
the biological behaviors that support the life-history needs of the
listed DPSs have been observed (e.g., the identified nursery grounds in
foreign waters). We are committed to increasing the awareness of the
threats to these listed DPSs and encourage the development of
conservation programs by foreign nations and international regulations
to protect these DPSs. For example, we recently collaborated with a
coalition of countries to gain support for a proposal to add three
hammerhead shark species (scalloped, smooth, and great) to Appendix II
of the Convention on the International Trade in Endangered Species of
Wild Fauna and Flora (CITES). In March 2013, at the 16th Meeting of the
Conference of the Parties to CITES, member nations, referred to as
``Parties,'' voted in support of this proposal, an action that will
complement existing international shark protection measures by ensuring
trade of these hammerhead shark species is sustainable and does not
threaten their survival. We will continue to be a leader in promoting
the conservation and management of sharks globally, and will work
internationally within regional fisheries management organizations and
other international bodies to promote the adoption of conservation and
management measures, particularly for the listed scalloped hammerhead
shark DPSs.
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 with 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.
Therefore, we conclude that for the Eastern Pacific DPS, Central & SW
Atlantic DPS, and the Indo-West Pacific DPS, there are no specific
areas within their respective ranges and under U.S. jurisdiction that
meet the definition of critical habitat. Since there is not any habitat
of scalloped hammerhead sharks in waters under U.S. jurisdiction that
is considered to be critical habitat, there is no critical habitat to
designate under ESA section 4(a)(3)(A)(i).
Although we have determined that no areas meet the definition of
critical habitat for the listed scalloped hammerhead DPSs, the areas
occupied by the DPSs under U.S. jurisdiction will continue to be
subject to conservation actions implemented under section 7(a)(1) of
the ESA, as well as consultation pursuant to section 7(a)(2) of the ESA
for Federal activities that may affect the listed scalloped hammerhead
DPSs, 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 these species and
their habitat. In addition, the prohibitions against importing,
exporting, engaging in foreign or interstate commerce, or ``taking'' of
the scalloped hammerhead sharks of the Eastern Pacific DPS and Eastern
Atlantic DPS under section 9 of the ESA continue to apply.
[[Page 71784]]
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: November 10, 2015.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
[FR Doc. 2015-29262 Filed 11-16-15; 8:45 am]
BILLING CODE 3510-22-P