EPA's Vessel General Permit and Small Vessel General

planktonic larvae form before settling and metamorphosizing on appropriate substrates,
preferably coralline algae (Bak 1977, Sammarco 1980, Rylaarsdam 1983). Initial calcification
ensues and develop into daughter corallites.
Studies indicate that larger colonies (as measured by surface area of the live colony) have higher
fertility and fecundity rates; colonies with a branch length longer than 3.5 inches were fertile and
over 80% of colonies with branches longer than 6.7 inches were fertile (Soong and Lang 1992).
Estimated size at sexual maturity is 6.7 inches in branch length and the smallest known
reproductive colony was 3.5 inches in branch length (Soong and Lang 1992).
Biological and physical factors affect spatial and temporal patterns of recruitment. These include
substrate availability and community structure, grazing pressure, fecundity, mode and timing of
reproduction, behavior of larvae, hurricane disturbance, physical oceanography, the structure of
established coral assemblages, and chemical cues (Lewis 1974, Birkeland 1977, Goreau et al.
1981, Rogers et al. 1984, Baggett and Bright 1985, Harriott 1985, Hughes and Jackson 1985,
Sammarco 1985, Morse et al. 1988, Fisk and Harriott 1990, Richmond and Hunter 1990).
Growth rates are relatively rapid, expressed as the linear extension of branches, ranging from 1.2
to 4.3 inches annually, and have enabled staghorn coral to construct significant reefs in several
locations throughout the Caribbean (Vaughan 1915, Jaap 1974, Adey 1978). Branching species,
such as acroporid corals, grow differentially in response to light such that coral polyp growth
maximizes exposure to available light (Kaniewska et al. 2009). During the 1970s there were vast
fields, or thickets, of staghorn coral on many reefs. The nominal situation in 2004 was isolated
branches and small thickets, 1.6 to 3.3 feet across. Growth can also occur from fragmentation
and dispersal (Tunnicliffe 1981, Bak and Criens 1982). A broken branch may be carried by
waves and currents to another location and, if favorable, branches grow into a new colony.
Rapid growth and fragment dispersal facilitate a competitive advantage for staghorn coral
relative to other coral and benthic species (Shinn 1976, Neigel and Avise 1983, Jaap et al. 1989).
Larval recruitment is influenced by the type and availability of benthic substrate, with certain
types of coral or rock substrates resulting in greater or lesser recruitment success (Ritson-
Williams et al. 2009).
Habitat
Historically, staghorn coral so dominated reef systems within the 23 to 49 feet depth that the area
became known as the staghorn zone. In other reef systems (Jamaica, Cayman Islands, Belize,
and eastern Yucatan), staghorn coral was a major mid-depth (33 to 82 feet) reef-builder (Adey
1977, 1978). Historically, staghorn coral was reported from depths ranging from surface to 200
feet, although it is considered rare below 66 feet (Goreau and Goreau 1973). In southeastern
Florida, this species historically occurred on the outer reef (52 to 66 feet), on spur, groove bank,
and transitional reefs, and on octocoral-dominated hard-bottom (Goldberg 1973, Davis 1982,
Jaap 1984, Wheaton and Jaap 1988). Colonies were common in back- and patch-reef habitats
(Gilmore and Hall 1976, Cairns 1982). Although staghorn coral colonies are sometimes found
interspersed among colonies of elkhorn coral, they are generally in deeper water or seaward of
the elkhorn zone and more protected from wave action.
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