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

AUGUST 2005 FINAL REPORT
2001; NMFS 2004c). Polychaetes are important food resources of reef fishes and invertebrates with
some species being indicators of environmental perturbation and reef condition (Bailey-Brock 2003).
Distribution—Polychaetes are primarily marine worms that are extremely abundant and widespread
in tropical and temperate oceans. There are very few brackish and freshwater forms living in streams
and estuaries of tropical regions (Colin and Arneson 1995). Islands in the tropical central and western
Pacific region have species-rich polychaete communities that are mostly cryptic, endolithic, or
infanual (Bailey-Brock 1995).
Habitat Preferences—Benthic coral reef polychaetes are associated with hard or softbottom
materials or live among marine vegetation (Bailey-Brock 1995). The polychaetes occupying all these
econiches in the coral reef biotopes and are classified into two groups: free-living (free-swimming)
errant and sedentary (tube-dwelling) segmented worms (Sorokin 1995). Specific types of coral reef
habitats frequently colonized by these polychaetes include rocky intertidal areas (e.g., tide pools and
shallow sand-filled depressions associated with lava rocks, basalt, and limestone benches), mud and
sand at the sediment-water interface, reef flats, sandy tops of patch reefs, sandy cays, seagrasses,
mangroves, and fleshy or thalloid algae (Bailey-Brock 1995; Sorokin 1995). In addition to coral reefs,
polychaetes also colonize vessel hulls, docks, and harbor walls as well as floating slippers, glass
floats, and debris (Bailey-Brock 1995). Polychaetes stabilize sand on reef flats by their tube-building
activities, bore into coral rock contributing to the erosion of reef materials, or are commensals of
sponges, mollusks, holothurians, and hydroids (Sorokin 1995).
Life History—Most polychaetes have separate sexes, although some are unisexual and a few
change sex. Fertilization of eggs takes place in the water column for species, which release their
gametes into the water. Other species mate and female retain the fertilized eggs within their body
cavities (Colin and Arneson 1995). Some species swarm in water during their breeding season,
others spawn during the first lunar cycle, and some undergo asexual breeding by simple division of
the body into several pieces (Sorokin 1995)
4.2.4.3.3 Sessile benthos management unit species
♦ Algae (Seaweeds)
Status—All algae (blue-green, green, brown, and red) are managed in Micronesia as part of the
PHCRT by the WPRFMC (2001). Over 370 species of algae occur in CNMI (137 species; WPRFMC
2001) and Guam (237 species; Lobban and Tsuda 2003) and have EFH designated within the
boundaries of the study area (WPRFMC 2001; NMFS 2004c). Algae are classified as EFH because
they are direct contributors to the well-being and protection of fish species, both as a source of food
and protection to larvae and small fish species (WPRFMC 2001). Currently, there is no fishery for
algal species in the American Flag Pacific Islands (WPRFMC 2001). Green, brown, and red algae are
commonly harvested for sale at local markets or used as bait for rod and reel fishing on Guam
(Hensley and Sherwood 1993). None of the species found in the study area are listed on the IUCN
Red List of threatened species (IUCN 2004).
Distribution—Algae are found worldwide along most shorelines and shallow-water environments. In
the Indo-Pacific they have a discontinuous distribution and a low level of endemicity (South 1993).
Habitat Preferences—Seaweeds are prominent organisms in the shallow-water photic zone ranging
from the spray zone well above the high tide level to depths as great as 268 m (South 1993). From
the intertidal to shallow subtidal zones, they occur on soft and/or hard substrata within a variety of
marine benthic habitats such as flat reefs, sheltered bays and coves, and rocky wave-exposed areas
along the shore or on the edge of the reef (Truno 1998). Algae occupy a wide range of habitats
including but not limited to: sandy bottoms of lagoons; shallow, calm fringing reefs; barrier reef coral
bommies; outer reef flats; and the outer reef slope (WPRFMC 2001). Coralline algae are of primary
importance in constructing algal ridges that are characteristic of exposed Indo-Pacific reefs
preventing oceanic waves from eroding coastal areas (WPRFMC 2001).
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