Title: U.S. Virgin Islands reef check surveys
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 Material Information
Title: U.S. Virgin Islands reef check surveys
Physical Description: Book
Language: English
Creator: Division of Fish and Wildlife, Department of Planning and Natural Resources
Publisher: Division of Fish and Wildlife, Department of Planning and Natural Resources
Place of Publication: St. Croix, USVI
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Bibliographic ID: CA01300931
Volume ID: VID00001
Source Institution: University of the Virgin Islands
Holding Location: University of Florida
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2003 US Virgin Islands Reef Check Surveys





Jason Vasques


Department of Planning and Natural Resources
Division of Fish and Wildlife


October 2003











Introduction
As part of a grant to assess benthic habitats in the US Virgin Islands the Division of Fish
and Wildlife (DFW) employed the Reef Check protocol to survey habitat, invertebrate
cover, and fish assemblages at two sites around St. Thomas. The Reef Check program is
a global volunteer program designed to provide public education and raise awareness of
the status of the world's reefs through the biological monitoring of key reef species. The
Reef Check program provides a broad assessment of reefs which may be repeated
annually for monitoring purposes. For more information of the Reef Check program see
Hodgson, et al. (2003) or the Reef Check website at http://www.reefcheck.org.

Methods and Site Selection
Great Bay- On 20 September 2003 two transects were surveyed in Great Bay, St.
Thomas. The transects in Great Bay were previously surveyed by Volson (2001).
Volson (2001) however, used a slightly different survey method. This site was selected
not only because it had been surveyed in the past but also because it is a nearshore reef
that may be influenced by anthropogenic impacts. The site is also within a marine
reserve. Transects 19 and 20 ran parallel to a linear reef. The transects were found by
using coordinates reported in Volson (2001) and finding the concrete blocks with PVC
pipes left by that study. Transect 19 was at a depth of 6.5 m and transect 20 was at a
depth of 8.5 m. Appendix 1 is the site description and coordinates for transects 19 and 20
as provided for Reef Check.

Savana Island- On 27 September 2003 two transects were completed at one site at
Savana Island, to the southwest of St. Thomas. This is an offshore cay that has no
population and is probably little affected by development and industry on St. Thomas.
There is however, commercial fishing and recreational diving around the island (see
Appendix 2 for the site description and coordinates). The reef at Savana Island is a linear
reef that lies in a semi-protected bay in the lee of the island. The deep transect was at a
depth of 13 m while the shallow transect ran at a depth of 7 m. Both transects followed a
contour parallel to shore.

Survey methods
At both sites the Reef Check protocol was used (see Hodgson, et al., 2003 for Reef
Check methods). This protocol was slightly modified to better fit the US Virgin Islands
needs. Modifications included a higher species resolution in the substrate surveys and the
addition of key species of fish and invertebrates that are important to the USVI.
Additional key fishes included; angelfishes, queen triggerfish, hamlets, and species level
identification of all grouper with size estimates for grouper. Conch were also added as a
key species in the invertebrate transect. Although conch are not necessarily a reef
organism, in the USVI they are often found near and among reefs and their presence may
be an indication of healthy conch populations. Two transects were conducted at each
site.

Results and Discussion
Great Bay- Tables 1 and 2 list the results of the substrate surveys conducted in Great
Bay at transects 19 and 20. In addition, coral bleaching occurred in 10% of the corals in









three of the four 20m transect segments along transect 19. Only one colony was damaged
by means other than bleaching, however, the mode of damage was not obvious. No
bleaching or damage was observed along transect 20.

Transect 20 was miss-placed and did not actually follow the original transect path. The
transect should have run along a slope (following a contour) that was dominated more by
hard corals. Instead it ran shoreward of the reef slope and spanned habitat more similar
to colonized hard bottom than coral reef. This may explain the high percent of sand,
rubble, and macroalgae in the substrate count as presented in Table 2.

The densities of key indicator species are presented in Table 3 for fish and invertebrates.
The most abundant fish were parrotfish across both transects. In Transect 20 parrotfish
counts included wrasse and also included fish of all size classes rather than just parrotfish
>20cm as specified in the Reef Check protocol. There were two grouper observed in the
belt transect, both were red hind approximately 30-35 cm TL. Gorgonians dominated
most of invertebrate counts across both transects.


Savana Island- The results of the substrate transects at Savana are presented in Tables 4
and 5. The shallow transect had a considerable amount of live coral cover with
Montastraea annularis being the most prominent. Hard coral accounted for a mean of 21
+ 4.32 of the possible 160 counts for the transect. The deeper transect had less coral
cover (mean of 9.25 + 1.5 out of 160 possible counts). No bleaching was observed in the
shallow transect and less than 5% and 10% of the colonies were bleached in the last two
20 m survey segments of the deeper transect. Black band disease was observed on two
colonies (one in each of the two transects). The diseased corals had damaged tissue on
5% of the colony in the deeper transect and 30% of the colony in the shallower transect.
Anchor damage was apparent on two colonies (one in each transect). This area has one
mooring and experiences moderate use by recreational divers and dive operations. The
site has a potential to be damaged by anchors over time.

The results of key indicator species surveys for fish and invertebrates are presented in
Table 6. The most abundant fish across both transects were parrotfish. Grouper were
observed in both transects. Ten grouper (coney n= 7, and red hind, n= 3) were
encountered in the shallow transect. Sizes for the coney were 10, 15, 10, 30, 10 20, and
20 cm TL. The red hind sizes were 15, 20, and 40 cm TL.


Literature Cited
Hodgson G; L Maun; C Shuman. 2003. Reef Check Survey Manual for Coral Reefs of
the Indo Pacific, Hawaii, Atlantic/Caribbean, Red Sea and Arabian Gulf. Reef Check,
Institute of the Environment, University of California Los Angeles, CA. 33p.

Volson, B. 2001. Benthic Habitat Assessment Project. Division of Fish and Wildlife,
Department of Planning and Natural Resources, USVI. Final Report F-7. 115 pp.












Table 1. Substrate composition for Great Bay transects 19 and 20 2003 using Reef Check
categories (mean of each category over four 20 m segments + std. dev.).


Transect 19


Transect 20


Hard coral 5.75 + 2.75 Hard coral 4 + 1.63
Soft coral 1.25 + 1.26 Soft coral 0.25 + 0.5
Recently killed coral 0 + 0.0 Recently killed coral 0 + 0.0
Nutrient indicator algae 9.25 + 4.57 Nutrient indicator algae 9.5 + 2.65
Sponges 3.5+ 1.73 Sponges 3.75 + 0.96
Rock (dead coral) 6.5 + 1.29 Rock (dead coral) 3.5 + 2.65
Rubble 4.25 + 2.87 Rubble 8.5 + 3.42
Sand 9.5 + 6.24 Sand 10.5 + 4.65
Silt/clay 0 + 0.0 Silt/clay 0 + 0.0
Other 0 + 0.0 Other 0 + 0.0











Table 2. Substrate composition to species level
(based on four 20 m segments).


for Great Bay in transects 19 and 20


Transect 19 _Transect 20*
Category Count Percent of transect Category Count Percent of transect


Sand


Rubble

Rock

Dead coral w/
algae
Macroalgae

Lobophora
variegata
Dictyota spp.

Halimeda spp.

Encrusting
sponge
Tube sponge

Rope sponge

Ircinia
strobilina
Erythropodium
sp.
Pseudopterogor
gia sp.
Eunicea sp.

Siderastrea
siderea
Siderastrea
radians
Montastraea
annularis
Agaricia
agaricites
Diploria
strigosa
Dichocoenia
stokesii
Madracis
mirabilis
Porites porites

Porites
astreoides
Millepora spp.


Sand


Rubble

Rock

Macroalgae

Sponges

Gorgonia
ventalina
Porites porites

Montastraea
annularis
Siderastrea
radians


* Transect 20 was not completed with the same level of resolution as transect 19.











Table 3. Density of key species at Great Bay transects 19 and 20
Transect 19 Transect 20
Fish Mean no./m2 + SD Fish Mean no./m2 + SD
Butterfly fish 0.03 + 0.008 Butterfly fish 0 + 0.0
Grunts and 0 + 0.0 Grunts and 0.003 + 0.005
Margates Margates
Snapper 0 + 0.0 Snapper 0.003 + 0.005
Nassau grouper 0 + 0.0 Nassau grouper 0 + 0.0
Grouper 0.005 + 0.006t Grouper 0 + 0.0
Hamlets 0.01 + 0.008 Hamlets 0.085 + 0.047
Parrotfish 0.015 + 0.024 Parrotfish 0.35 + 0.148*
Angelfish 0.008 + 0.015 Angelfish 0 + 0.0
Moray eel 0 + 0. Moray eel 0 + 0.0
Invertebrates Invertebrates
Banded coral 0.0075 + 0.0096 Banded coral 0 + 0.0
shrimp shrimp
Diadema urchin 0.005 + 0.006 Diadema urchin 0 + 0.0
Pencil urchin 0.008 + 0.0096 Pencil urchin 0 + 0.0
Triton shell 0 + 0.0 Triton shell 0 + 0.0
Flamingo tongue 0.02 +0.022 Flamingo tongue 0.003 + .005
Gorgonian 0.32+0.124 Gorgonian 0.048 + 0.021
Sea egg 0.05 + 0.010 Sea egg 0.005 + 0.01
(Tripnustes) (Tripnustes)
Lobster 0 + 0.0 Lobster 0 + 0.0
Conch 0.003 + 0.005 Conch 0 + 0.0
Grouper were Epinephelus guttatus
* this count included parrotfish and wrasses of all sizes


Table 4. Substrate composition for Savana Island shallow and deep transects 2003 using
Reef Check categories (mean of each category over four 20 m segments + std. dev.).


Shallow (Depth = 7m)


Deep (Depth = 13m)


Hard coral 21 + 4.32 Hard coral 9.25 + 1.50
Soft coral 4.5 + 1.00 Soft coral 3 + 2.16
Recently killed coral 0 + 0.0 Recently killed coral 0 + 0.0
Nutrient indicator algae 4.5 + 0.58 Nutrient indicator algae 9.25 + 5.12
Sponges 1+ 1.41 Sponges 3.75 + 0.96
Rock (dead coral) 4.5 + 1.73 Rock (dead coral) 6 + 1.15
Rubble 1.25 + 1.26 Rubble 1.5 +1.29
Sand 3 + 2.94 Sand 7 + 4.55
Silt/clay 0 + 0.0 Silt/clay 0 + 0.0
Other 0.25 +0.50 Other 0.5 +0.58














Table 5. Substrate composition to species level for Savana Island shallow and deep
transects (based on four 20 m segments).
Shallow transect Deep Transect
Category Count Percent of transect Category Count Percent of transect


Acropora
cervicornis

Agaricia agaricites
Dead coral w/ algae

Dichocoenia stokesii

Dictyota sp
Diploria sp

Diploria strigosa

encrust sponge

Erythropodium
Eunicea sp
Lobophora variegata
Millepora alcicornis
Montastraea
annularis
Montastraea
cavernosa
Plexaura homomalla

porites astreoides
porites porites

Pseudoplexaura sp


18.8


Rubble


Rock


Sand
Siderastrea siderea

Solenastrea sp
tube sponge
unknown


Agaricia
agaricites
Agaricia
lamarcki
Agelas conifera
Amphimedon
compressa
Aplysina
fistularis
Aplysina sp
Briareum
asbestinum
Dead coral w/
algae
Dichocoenia
stokesii
Dictyota sp
encrust sponge
Eunicea sp
Eusmilia
fastigiana
Lobophora
variegata
Madracis sp
Meandrina
meandrites
Millepora sp
Montastraea
annularis
Montastraea
cavernosa
Plexaura
homomalla
Porites
astreoides
Porites porites
Pseudoplexaura
sp
Rubble
Rock
Sand
Siderastrea
radians
Siderastrea
siderea
unknown


14.4


1.9
3.8
0.6
17.5













Table 6. Density of key species at Savana Island transects
Shallow transect Deep transect
Fish Mean no./m2 + SD Fish Mean no./m2 + SD
Butterfly fish 0.008 + 0.010 Butterfly fish 0.005 + 0.006
Grunts and 0.005 + 0.010 Grunts and 0 + 0.0
Margates Margates
Snapper 0.008 + 0.02 Snapper 0 + 0.0
Nassau grouper 0 + 0.0 Nassau grouper 0 + 0.0
Grouper 0.03 + 0.021t Grouper 0.005 + 0.006*
Hamlets 0.02 + 0.010 Hamlets 0.003 + 0.005
Parrotfish 0.04 + 0.018 Parrotfish 0.018 + 0.017
Queen 0 + 0.0 Queen 0 + 0.0
Triggerfish Triggerfish
Angelfish 0 + 0.0 Angelfish 0 + 0.0
Moray eel 0 + 0. Moray eel 0 + 0.0
Invertebrates Invertebrates
Banded coral 0 + 0.0 Banded coral 0.005 + 0.010
shrimp shrimp
Diadema urchin 0.003 + 0.005 Diadema urchin 0 + 0.0
Pencil urchin 0 + 0.0 Pencil urchin 0 + 0.0
Triton shell 0.003 + 0.005 Triton shell 0 + 0.0
Flamingo tongue 0.023 + 0.017 Flamingo tongue 0.018 + 0.024
Gorgonian 1.26 + 0.437 Gorgonian 1.79 + 0.495
Sea egg 0 + 0.0 Sea egg 0 + 0.0
(Tripnustes) (Tripnustes)
Lobster 0.005 + 0.010 Lobster 0 + 0.0
Conch 0 + 0.0 Conch 0 + 0.0
Grouper were Epinephelus guttatus and Cephalopholisfulva
* Grouper were Epinephelus guttatus and Cephalopholisfulva




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