Marine Resources Assessment for the Marianas Operating ... - SPREP

AUGUST 2005 FINAL REPORT
the species found in the study area are listed on the IUCN Red List of threatened species (IUCN
2004).
Distribution—The Carangids are a large family represented in all tropical and temperate seas with
the majority being found in coral reef waters (Allen and Steene 1987; Myers 1999).
The mackerel scad is a circumtropical species and is widespread throughout the Indian Ocean. This
species ranges from the Indo-West Pacific to the Marquesas Islands in the east, and from Japan in
the north, south to Australia (Smith-Vaniz 1999). The mackerel scad can be found from the Carolines
to the Marianas in Micronesia (Myers 1999).
Bigeye scad range from Japan and the Hawaiian Islands in the north, south to New Caledonia and
Rapa, and throughout Micronesia (Myers 1999). This species can be found off the coast of Guam
year round but is scarce in July and August, which may be due to spawning (Uchida 1983).
Habitat Preferences—Carangid eggs are planktonic and larvae are common in nearshore waters.
Juveniles can be found in nearshore and estuarine waters and occasionally form small schools over
sandy inshore reef flats (Myers 1999). Adults are widely distributed in shallow coastal waters,
estuaries, shallow reefs, deep reef slopes, banks, and seamounts (WPRFMC 2001). Adult Carangids
can range from reef habitats to deep slope habitats at depths of 0 to 350 m (WPRFMC 2001).
Mackerel scad are a schooling species that are most often found in open water and frequently in
insular habitats. This species can be found near the surface, but is commonly taken at depths from 40
to 200 m (Froese and Pauly 2004).
Small to large schools of bigeye scad are typically found inshore or in shallow-water and occasionally
over shallow reefs in turbid water to depths of 170 m (Smith-Vaniz 1999). Large schools of bigeye
scad appear seasonally in the Marianas from August to November in shallow sandy lagoons, bays,
and channels (Myers 1999).
Life History—Carangid species spawn in pairs within larger aggregations associated with the lunar
cycle. Little is known about the reproduction of these species but peak spawning occurs between May
and August (WPRFMC 2001).
Decapterus spp. and Selar spp. tend to spawn in pelagic environments. Eggs are also found in
pelagic waters and after hatching, larvae and juvenile fish remain in the pelagic environment where
they frequently form large aggregating schools. Juvenile aggregations have been identified as far as
90 miles (mi) offshore. Larval and juvenile fish remain in offshore pelagic waters for the first several
months of their life, after which they migrate to the nearshore adult habitat. Spawning occurs from
March to August, peaking from May to July (WPRFMC 2001).
EFH Designations—(WPRFMC 2001; Figures D-10, D-14, and D-18; Table 4-5)
Eggs and Larvae―The water column from the shoreline to the outer boundary of the EEZ to
a depth of 100 m.
Adult and Juveniles―All bottom habitat and the adjacent water column from 0 to 100 m.
♦ Carcharhinidae (Requiem Sharks)
Status—Five carcharhinid sharks are managed in Micronesia as part of the CHCRT by the WPRFMC
(2001) and occur in CNMI and Guam (Amesbury and Myers 2001; Myers and Donaldson 2003). All
have EFH designated within the boundaries of the study area (WPRFMC 2001; NMFS 2004c). In
addition, the four other species of requiem sharks found in the study area have EFH designated
under the PHCRT (WPRFMC 2001). Currently, no data are available to determine if requiem sharks
of the CHCRT are approaching an overfished situation (NMFS 2004a). Of the nine sharks managed
under CHCRT/PHCRT in the study area, five are listed on the IUCN Red List of threatened species.
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