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

AUGUST 2005 FINAL REPORT
Seaward reefs, outer deep reef slopes, banks, and deeper waters of coral reefs comprise the slope areas
(Heemstra and Randall 1993; Allen 1985; Myers 1999; Amesbury and Myers 2001; Allen and Adrim
2003). The deep-water complex inhabits areas of high relief with hard rocky bottoms such as steep
slopes, pinnacles, headlands, rocky outcrops, and coral reefs (Allen 1985; Parrish 1987; Haight et al.
1993).
Life History—Very little is known about the ecology (life history, habitat, feeding, and spawning) of the
bottomfish species managed in the area (WPRFMC 1998). However, limited information is available for
various larval, juvenile, and adult bottomfish genera of the shallow-water and deep-water complexes.
Within the shallow-water complex, snappers form large aggregations and groupers/jacks occur in pairs
within large aggregations near areas of prominent relief. Spawning coincides with lunar periodicity
corresponding with new/full moon events (Grimes 1987; Myers 1999; Amesbury and Myers 2001).
Groupers have been shown to undergo small, localized migrations of several kilometers to spawn
(Heemstra and Randall 1993). Large jacks are highly mobile, wide-ranging predators that inhabit the open
waters above the reef or swim in upper levels of the open sea (Sudekum et al. 1991) and spawn at
temperatures of 18° to 30°C (Miller et al. 1979).
Within the deep-water complex, snappers aggregate near areas of bottom relief as individuals or in small
groups (Allen 1985). Snappers may be batch or serial spawners, spawning multiple times over the course
of the spawning season (spring and summer peaking in November and December), exhibit a shorter,
more well-defined spawning period (July to September), or have a protracted spawning period (June
through December peaking in August) (Allen 1985; Parrish 1987; Moffitt 1993). Some snappers display a
crepuscular periodicity and migrate diurnally from areas of high relief during the day at depths of 100 to
200 m to shallow (30 to 80 m), flat shelf areas at night (Moffitt and Parrish 1996). Other snapper species
exhibit higher densities on up-current side islands, banks, and atolls (Moffitt 1993).
EFH Designations—(WPRFMC 1998; Figures D-1, D-2, and D-3; Table 4-2)
Eggs and Larvae―EFH for these life stages is the water column extending from the shoreline to
the outer limit of the EEZ down to a depth of 400 m and encompasses both the shallow-water and
deep-water complexes.
Juveniles and Adults—For these life stages, EFH encompasses the water column and all bottom
habitat extending from the shoreline to a depth of 400 and includes the shallow-water and deepwater
complexes.
HAPC Designations—(WPRFMC 1998; Figures D-1, D-2, and D-3). Based on the known distribution
and habitat requirements, all life stages of the BMUS have HAPC designated in the study area that
includes all slopes and escarpments between 40 and 280 m.
4.2.2 Pelagic Management Unit Species
Status—Thirty-three species are currently managed as PMUS by the WPRFMC through the Fishery
Management Plan for the Pelagic Fisheries of the Western Pacific Region (WPRFMC 1986b) and
subsequent amendments (WPRFMC 1998). PMUS are divided into the following species complex
designations: marketable species, non-marketable species, and sharks (Table 4-1). The designation of
these complexes is based on the ecological relationships among the species and their preferred habitat
(WPRFMC 1998). The marketable species complex has been further divided into temperate and tropical
assemblages. The temperate species complex includes those PMUS that are found in greater abundance
outside tropical waters at higher latitudes (e.g., broadbill swordfish, Xiphias gladius; bigeye tuna, Thunnus
obesus; northern bluefin tuna, T. thynnus; and albacore tuna, T. alalunga). Additionally, a potential squid
PMUS consisting of three flying squid species has been proposed by the WPRFMC for incorporation into
the existing PMUS (NMFS-PIR 2004).
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