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

AUGUST 2005 FINAL REPORT
substrate to mature (primarily a complex reef habitat; Bailey-Brock 2003). Feather-duster worms can
also propagate by fragmentation. They can also regenerate body parts (Hawaii Biological Survey
2001a).
4.2.4.3 Potentially Harvested Coral Reef Taxa
The PHCRT are managed under the FMP for the CRE by the WPRFMC (2001). Taxa included under
PHCRT consist of thousands of coral reef associated species, families, or subfamilies that encompass
fish, invertebrate, and sessile benthos MUS (WPRFMC 2001). These MUS are limited to those
families/species known or believed to occur in association with coral reefs during some phase of their life
cycle (WPRFMC 2001). Since little information is available about life histories and habitat of this biota
beyond general taxonomic and distributional descriptions, WPRFMC has adopted a precautionary
approach in designating EFH for PHCRT.
EFH for all life stages of PHCRT is designated as the water column and bottom habitat from the shoreline
to the outer boundary of the EEZ to a depth of 100 m (Figure D-22, D-23, and D-24; Table 4-5;
WPRFMC 2001).
A complete list of the PHCRT occurring in the study area is found in Table 4-1. All of the family,
subfamily, or species that are listed in the CHCRT also occur on the PHCRT list. Descriptions of these
taxa will be presented only in the CHCRT section. Descriptions of the individual families, subfamilies, or
species comprising the fish, invertebrate, and sessile benthos MUS are described in the following
paragraphs.
4.2.4.3.1 Fish management unit species
♦ Sphyrnidae (Hammerhead Sharks)
Status—Two species of hammerhead sharks are managed in Micronesia as part of PHCRT by the
WPRFMC (2001). Only the scalloped hammerhead (Sphyrna lewini) has been reported from the
CNMI and Guam (Myers and Donaldson 2003) and has EFH designated within the boundaries of the
study area (WPRFMC 2001; NMFS 2004c). Currently, there is no data available to determine if the
scalloped hammerhead of the PHCRT is approaching an overfished situation (NMFS 2004a).
Hammerhead sharks are generally caught in low numbers as part of longline fishery (NMFS-PIR
2001) and are readily available to inshore primitive and small commercial fisheries (Compagno 1998).
This species is listed on the IUCN Red List of threatened species as near threatened (Kotas 2000).
Distribution—Hammerheads are wide-ranging, coastal-pelagic, and semi-oceanic sharks that inhabit
tropical and warm temperate waters which occur over continental and insular shelves (Compagno
1984, 1998).
Habitat Preferences—Hammerhead sharks are found in a wide variety of coral reef habitats
(Hennemann 2001). They are very active swimmers occurring in pairs, in schools or solitary, ranging
from the surface, surfline, and intertidal region down at least 275 m depth (Compagno 1984).
Juveniles often occur in schools frequently inhabiting inshore areas such as bays, seagrass beds,
and lagoon flats for foraging near the bottom before moving into deeper waters as adults (WPRFMC
2001). As adults, they can be found in shallow inshore areas during mating or birthing events
(Compagno 1984).
Life History—Hammerhead sharks make long seasonal, north-south migrations to warmer waters in
the winter and cooler waters in the summer (Hennemann 2001). They are viviparous, having a
gestation period of about 12 months (WPRFMC 2001). The scalloped hammerhead produces an
offspring of 15 to 31 pups per liter and utilizes shallow, turbid coastal waters (e.g., Guam’s inner Apra
Harbor) as nursery areas (Compagno 1984; Myers 1999).
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