Title: Coral Reefs of the Virgin Islands
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Permanent Link: http://ufdc.ufl.edu/CA01300972/00001
 Material Information
Title: Coral Reefs of the Virgin Islands
Physical Description: Book
Language: English
Creator: U.S. Virgin Islands
Publisher: U.S. Virgin Islands
Place of Publication: U.S. Virgin Islands
Publication Date: 2005
 Record Information
Bibliographic ID: CA01300972
Volume ID: VID00001
Source Institution: University of the Virgin Islands
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.

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Coral Reefs of the Virgin Islands


Tropical coral reefs are complex associations of thousands of
species of plants and animals. Hard corals make up the basic
physical structure of the reef. Corals are colonial animals,
meaning they live together in a large group. The holes in a piece
of coral each contain a small animal called a polyp, which
resembles a sea anenome. The polyps are able to extract dissolved
calcium carbonate from the surrounding sea water. They use it to
build the stony skeleton which makes up the coral. This skeleton
grows in many different forms, depending on the species of coral.



SCoral Polyps




The living coral tissue that covers the skeleton contains
microscopic symbiotic algae called zooxanthellae which remove
carbon dioxide and other metabolites from the coral and provide it
with oxygen through photosynthesis. Many of the most common hard
corals, such as elkhorn, pillar, star, finger and brain corals are
named for their interesting shapes.



Large Star Coral




Coral reefs thrive in tropical conditions where the water
temperature stays between 70 and 850 F, with clear water, bright
sunlight and stable salinity. Clear water and a relatively
shallow depth with plenty of sunlight allow the symbiotic algae to
photosynthesize and enable the corals to grow faster. Reefs may
form near shore or may be found scattered across the insular shelf
many miles from land. Reefs generally form on rocky outcroppings
on the sea bottom where corals find a solid surface to attach.
Gentle wave action helps remove sediment which could suffocate the
coral polyps, but rough seas caused by storms can cause reef
damage. Sediment- free water allows the corals to feed on
planktonic organisms in the water. The health of the coral reef
depends upon a delicate natural balance.















Pillar Coral


Coral is very fragile, even though it may appear to be hard like
rock. Handling or stepping on coral kills the coral polyps.
Sediments from land that wash into the sea can smother the coral.
Runoff from land muddies the water, blocking the sunlight needed
for the symbiotic algae to photosynthesize. When this happens,
the coral becomes unhealthy. Changes in the water's salt content
caused by flooding or the discharge of hot, salty water from
desalination plants can also harm coral. Chemical and waste
pollution in our waters is hazardous to coral reefs and sea life.
Anchoring on coral reefs can crush or break off entire coral
colonies. Plastic bags discarded into the ocean can cover corals,
literally smothering the life from them. Overfishing can unbalance
the coral reef when too many fish of a particular species are
caught.
Many reef corals are becoming affected by a variety of
diseases. It is not known what causes these diseases but some may
be transported from land by sediment runoff. These diseases are
having a serious affect on some of our reefs. The first evidence
of disease is bleaching of the coral as it expels the symbiotic
algae due to stress.




Lag n Reef Crest

Seagrasses S Forereef
Reef

Caribbean Reef Cross-section
Sand/
SAlgal
Plain ,.


Coral reefs are the underwater equivalent of rainforests in
their diversity of species. They provide food, habitat and shelter
for a variety of marine animals. Many of the fish we eat live on
the reef or spend part of their lives there. Fishermen depend on
the reefs for their livelihood. Reefs can also act as a barrier,










slowing down waves before they reach the shore. This helps reduce
shoreline erosion, and may create an area of calm water where
seagrass beds and mangroves can grow. As coral reefs naturally
degrade from wave action and such things as parrot fish scraping
the dead corals for algae, sand is formed which produces and
maintains our beaches. Our tourism depends in large part on the
health of our reefs and waters as an attractant for visitors.
The physical and chemical damage our reefs are being
subjected to by human activities is causing the loss of this
valuable resource. Without them, our shorelines will begin to
erode from wave action. Our beaches will lose more sand than will
be produced, causing a net loss of beaches. Our fishermen and
associated businesses will lose their source of income. Tourism
will decline as people travel elsewhere to enjoy and experience
clean, healthy marine ecosystems.
Therefore, when visiting our coral reefs, do not damage them.
Anchor in sand. Return your garbage to shore. Take only the fish
you can eat. Don't touch the corals. When on land, dispose of
waste oil properly. Keep sediment out of the water by using
sediment control measures on your land.


Red Hind










St. Thomas Coral Reefs


1. Stumpy Bay
2. Santa Maria/Hendricks Bay
3. Caret Bay
4. Neltjeberg Bay
5. Inner Brass Island
6. Hull Bay
7. Magens Bay
8. Hans Lollik Island
9. Thatch Cay
10. Lindquist Bay
11. Pelican Beach/Prettyklip Point
12. Great Bay
13. Great St. James "Bareass" Bay
14. Whelk Rocks
15. Little St. James
16. Cow and Calf Rocks
17. Cas Cay to Long Point
18. Bolongo Bay
19. Water Island
20. Saba Island
21. Black Point
22. Perseverance Bay

Note: This map shows only the main nearshore coral reefs around
St. Thomas. These reefs are all accessible by snorkling and are
generally less than 30 feet in depth. Many other areas have coral
communities living on hard bottom but are not considered true
coral reefs.



















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St. John Coral Reefs


1. Turtle Bay 26. Reef Bay
2. Hawksnest Bay 27. Fish Bay
3. Denis Bay 28. Rendezvous Bay
4. Jumby/Trunk Bays 29. Maria Bluff
5. Johnson's Reef 30. Moravian Point and shoals
6. Windswept Point 31. Stevens Cay
7. Cinnamon Cay
8. Whistling Cay Shoals
9. Mary's Point/Creek
10. Waterlemon Cay
11. Threadneedle Point
12. Brown Bay
13. Mennebeck Bay
14. Haulover Bay
15. Newfound Bay
16. East End Reefs
17. Harbor Point
18. Lagoon Point
19. LeDuck Island
20. Friis Bay
21. John's Folly
22. Ram Head
23. Kiddel Bay
24. Grootpan Bay
25. Lameshur/Europa Bays
Note: This map shows only the main nearshore coral reefs around
St. John. These reefs are all accessible by snorkling and are
generally less than 30 feet in depth. Many other areas have coral
communities living on hard bottom but are not considered true
coral reefs.









































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St. Croix Coral Reefs


1. Rust-Op-Twist
2. Salt River
3. White Horse Reef
4. Long Reef
5. Green Cay
6. Buck Island
7. Tague Bay Bank Barrier Reef System
8. Northeast Bank Barrier Reef System
9. East End Bay
10. Isaac Bay
11. Jack Bay
12. Grapetree Bay

Southeast St. Croix Bank Barrier Reef System:
13. Turner Hole
14. Rod Bay
15. Robin Bay
16. Great Pond
17. Fareham Bay to Canegarden Bay

Note: This map shows only the main nearshore coral reefs around
St. Croix. These reefs are all accessible by snorkling and are
generally less than 30 feet in depth. Many other areas have coral
communities living on hard bottom but are not considered true
coral reefs. St. Croix has an extensive bank barrier reef system
not found in the other Virgin Islands. These produce productive
back reef lagoons which contain a high diversity of marine plants
and organisms.








































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