A summary of the Dry Tortugas National Park Long Term Monitoring
and Assessment Project (DRTO CREMP) results through 2005.
*Not included in this summary is data from two Dry Tortugas
sites where sampling began in 1999 as part of the Florida Keys
National Marine Sanctuary (FKNMS) CREMP.
Dry Tortuagas National Park Survey
Long-term Status and Trends from 2004 to 2006 for the
Coral Reefs of the Dry Tortugas National Park
Scleractinian Species (Stony Coral) Inventory
- In 2005, a total of 29 stony coral species were identified for
the 23 Dry Tortugas monitoring stations compared to 33 total
species in 2004.
- In 2005, five species were present at all survey stations;
Porites astroides, Millepora alcicornis,
Montastrea annularis (species complex), Diploria
strigosa, and Agaricia agaricites.
- The mean, or average, number of stony coral species per station
decreased from 2004 to 2005 at five of the six study sites that
have data for both years.
- In 2005, bleaching or disease was recorded at 18 of 23 survey
Video Transect Survey
- The mean percent cover of stony corals per station for all of
the Dry Tortugas decreased from 2004 (7.2 percent) to 2005 (6.7
percent). This decline was not statistically significant.
- Statistically significant declines from 2004 to 2005 were found
at two sites: Bird Key (12.6 percent to 11.3 percent) and Prolifera
Patch (15.1 percent to 13.8 percent). These two sites had the
highest mean percent of stony coral cover for both years. With the
exception of Palmata Patch (mean percent stony coral cover of
roughly 5.5 percent for both years), no other site had stony coral
cover above five percent.
- At Bird Key the coral species with the highest mean percent of
cover across all survey stations were Montastrea annularis, M.
cavernos, Colpophyllia natans, and Siderastrea siderea.
- When averaged across all stations for each site, octocorals are
the most abundant taxonomic group at five of the seven Dry Tortugas
- At Temptation Rock the mean percent cover of the zoanthid
Palythoa caribaeorum (about 13 percent for 2004 and 2005)
is much higher than at any other survey site.
Clionid Sponge Survey
- The mean clionid sponge area per station for each site
decreased from 2004 to 2005 at five of the seven survey sites.
- Palmata Patch had no clionid sponges in either year.
- At White Shoal the mean clionid cover is below 0.5 centimeters
squared/meters squared (cm2/m2) for both
years, but increased slightly from 2004 to 2005.
- The coral species most affected by clionid sponges are
Montastrea annularis (complex), M. cavernosa, and Siderastrea
Octocoral Abundance Survey
*This survey was conducted at only one site, Mayer's Peak.
- Octocorals from 10 different genera, or classifications, were
observed at Mayer's Peak in 2005, the first year of the Octocoral
- The most common Octocoral genera were Briareum (six
colonies/meters squared [m2]) Erythropodium (five
colonies/m2), Eunicea (4.5 colonies/m2), and
Pseudopterogorgia (four colonies/m2).
As shown by the two Dry Tortugas sites monitored since 1999, see
the CREMP 2007 executive summary, coral cover has been declining in
the Dry Tortugas for several years. Although significant declines
are not observed at most survey sites, decreases in coral cover
have continued from 2004 -2005. The frequency and intensity of
tropical storms and hurricanes that have passed over this area
during this time period may have contributed to the observed
declines. Continued monitoring of these sites is necessary in order
to understand how coral reefs are changing in Dry Tortugas National
View the complete Dry Tortugas National Park (DRTO) Long Term
Monitoring and Assessment Project 2007 Annual Report (3.65
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The DRTO CREMP 2007 Annual Report was prepared by the Fish and
Wildlife Research Institute
To obtain DRTO CREMP Annual Reports from previous years or
inquiry about CREMP data please contact the Fish and Wildlife
Research Institute corals group at Corals@MyFWC.com
Learn more about CREMP field and
Funding for DRTO CREMP has been provided by the National Parks Service