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

AUGUST 2005 FINAL REPORT
♦ Octopodidae (Octopuses)
Status—Two species of Octopus are managed in Micronesia as part of the CHCRT by the WPRFMC
(2001) and are reported as occurring in CNMI and Guam (Ward 2003). Both species have EFH
designated within the boundaries of the study area (WPRFMC 2001; NMFS 2004c). In addition, the
remaining 22 species of octopus found in the study area have designated EFH under the PHCRT
(WPRFMC 2001). Currently, no data are available to determine if octopuses of the CHCRT are
approaching an overfished situation (NMFS 2004a). These species are primarily harvested for human
consumption but are also used as bait in other fisheries (Norman 1998). None of the species found in
the study area are listed on the IUCN Red List of threatened species (IUCN 2004).
Distribution—Members of the family Octopodidae occur in all the oceans of the world from the
equator to polar latitudes (Norman 1998, Waikiki Aquarium 1998a). The day octopus, Octopus
cyanea, and the night octopus, O. ornatus, are found widely throughout the shallow-waters of the
Indo-West Pacific from Hawai’i in the east to the east African coast in the west. This species has
been reported as far north as Japan and as far south as New South Wales, Australia (Norman 1998).
Habitat Preferences—Reef-associated octopuses are bottom-dwelling species that usually occupy
holes and crevices or coral areas. These species are found from the shallowest part of the reef down
to approximately 50 m (WPRFMC 2001). Octopuses occur on a wide range of substrates including
coral and rock reefs, seagrass beds, sand, and mud. Octopus eggs are demersal and typically
attached in clusters within the rocky depths of the reef (WPRFMC 2001).
The day octopus and night octopus are found from intertidal reefs, shallow reef flats and reef slopes
to depths of at least 25 m and are associated with both live and dead corals. As the name implies the
day octopus is more active throughout day with peak activities at dusk and dawn (Norman 1998). The
night octopus is nocturnal, resting by day and foraging at night (Waikiki Aquarium 1998a).
Life History—Life history information is lacking for these species of octopus (WPRFMC 2001). Eggs
are demersal and females tend the eggs until they hatch. Octopuses may migrate up to 100 m in
search of food (Norman 1998, Waikiki Aquarium1998a).
EFH Designations—(WPRFMC 2001; Figures D-10, D-14, and D-18; Table 4-5)
Eggs, Juvenile, and Adult―EFH for the adult, juvenile phase and demersal eggs are defined
as all coral, rocky, and sand-bottom areas from 0 to 100 m.
♦ Polynemidae (Threadfins)
Status—One species, the sixfeeler threadfin (Polydactylus sexfilis), of the family Polynemidae is
managed in Micronesia as part of the CHCRT by the WPRFMC (2001) and has been reported as
occurring in CNMI and Guam (Amesbury and Myers 2001; Myers and Donaldson 2003). EFH has
been designated within the boundaries of the study area (WPRFMC 2001; NMFS 2004c) for this
species. Currently, no data are available to determine if the sixfeeler threadfin of the CHCRT is
approaching an overfished situation (NMFS 2004a). This species is highly valued as food-fish
(WPRFMC 2001). This species is not listed on the IUCN Red List of threatened species (IUCN 2004).
Distribution—The sixfeeler threadfin is found throughout the tropical waters of the Atlantic and Indo-
Pacific Oceans from 30°N to 0°N (WPRFMC 2001; Froese and Pauly 2004). In the Indo-Pacific this
species ranges from India to the Hawaiian, Marquesan, and Pitcairn Islands, north to the Yaeyama
and Bonin Island, and throughout Micronesia (Myers 1999).
Habitat Preferences—Adult sixfeeler threadfin are found near reef areas and inhabits turbid waters
along sandy shorelines and over sandy lagoon bottoms usually associated with high-energy surf
zones (Myers 1999; Feltes 2001; WPRFMC 2001). This species is most common at depths from 20
to 50 m (Feltes 2001). Sixfeeler threadfin eggs and larvae are pelagic but after larval metamorphosis
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