EPA's Vessel General Permit and Small Vessel General

Nemoto 1959, Nemoto 1970, Krieger and Wing. 1984, Krieger and Wing. 1986). Because most
humpback prey are likely found above 300 m depths, most dives are probably relatively
shallow, with typical diving depths of approximately 60-170 m (Hamilton et al. 1997). Dives
usually range between two and five minutes but can last to around 20 minutes (Dolphin 1987).
Invertebrates
Elkhorn coral
Description of the species
Although they resemble plants, elkhorn coral is a colony of invertebrates that collaboratively
form frond-like branches radiating from a central trunk that is firmly attached to the sea floor.
The largest species of its genus, colonies can reach at least 6.6 feet high and 13 feet in diameter
(Veron 2000). Corallites (branches of radial arms of calcium carbonate) are tube-like and
porous, 0.08 inch to 0.16 inch long, about 0.08 inch in diameter, white near the growing tip, and
brown to tan away proximally.
Distribution
Elkhorn coral is found widely in the Caribbean, including in the Florida Keys, Abaco Island (The
Bahamas), Alacran Reef, Mexico, Belize, Colombia, Costa Rica, Guatemala, Honduras,
Nicaragua, Panama, Venezuela, Bonaire, Cayman Islands, Jamaica, Puerto Rico, US Virgin
Islands, Navassa, and throughout the West Indies (Goreau 1959, Kornicker and Boyd 1962, Storr
1964, Scatterday 1974, Jaap 1984, Dustan and Halas 1987, NMFS 2006a). However, abundance
within the distribution is reduced, largely due to water temperature and quality issues.
Growth and reproduction
Elkhorn corals employ both sexual and asexual reproduction. Sexual reproduction is
accomplished by releasing sperm and egg during spawning events. Colonies are referred to as
simultaneous hermaphrodites, meaning that a given colony contains both female and male
reproductive sex organs (Szmant 1986). Spawning events are relatively short, with gametes
released only a few nights during July, August, and/or September. In some populations,
spawning is synchronous after a full moon. Annual egg production in Puerto Rico was estimated
to be 3,870 to 5,100 eggs per square inch of living coral tissue (Szmant 1986). Once fertilization
occurs, 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; over 80% of the colonies larger than 620 inches 2 were fertile.
Estimated colony size at sexual maturity was 248 inches 2 and the smallest reproductive colony
observed was 6.3 inches 2 by 3.15 inches 2 (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
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