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Coral Reef Evaluation and Monitoring Project 2007 Executive Summary

Long-term status and trends from 1996 to 2006 for the corals reefs of the Florida Keys National Marine Sanctuary

(Summarized results)

• From 1996 to 2006 the mean, or average, number of stony coral species per station decreased from 18 to 13 in the lower keys (Key West to Moser Channel); decreased from 17 to 14 in the middle keys (Moser Channel to Lower Matecumbe Key); and decreased from 16 to 12 in the upper keys (Lower Matecumbe Key to Key Largo). These declines were fairly consistent through time, but are not statistically significant.
• From 2005 to 2006 the mean number of stony coral species per station decreased by two species in the lower keys and decreased by one species in the middle keys and upper keys. Analysis of this data is incomplete.

Dry Tortugas 

• From 1999 to 2006 the mean number of stony coral species per station decreased from 22 to 17. The largest change was observed from 2003 to 2004. Analysis of this data is incomplete.
• From 2005 to 2006 the mean number of stony coral species per station decreased by less than one species.

• In the lower keys from 1996 to 2006 the mean percent cover of stony corals per station decreased from 15 to 7 percent. The largest decrease was observed from 1997 (15 percent) to 1999 (nine percent). Since 1999 stony coral cover has steadily decreased. 
• In the middle keys from 1996 to 2006 the mean percent cover of stony corals per station decreased from seven to five percent. The largest decrease was observed from 1997 (seven percent) to 1999 (five percent). Since 1999 stony coral cover has remained the same. 
• In the upper keys from 1996 to 2006 the mean percent cover of stony corals per station decreased from 12 to 6 percent. The largest decrease was observed from 1996 (12 percent) to 1999 (seven percent). From 1999 to 2005 stony coral cover remained the same, but from 2005 to 2006 a notable decrease occurred. 
• These decreases in mean percent coral cover have been mainly attributed to the demise of three species Montastrea annularis (species complex), Acropora palmata, and the hydrocoral Millepora complanata.
• In the Florida Keys the five most abundant species throughout the course of the study have been M. annularis (species complex), M. cavernosa, Siderastrea siderea, Porites astroides, and Colpophyllia natans.
• The percent cover of M. annularis averaged across all stations in the Florida Keys decreased drastically from 1997 (4.5 percent) to 2000 (three percent) and continued to decrease steadily from 2000 to 2006 (2.5 percent). The percent cover of the other four species averaged across all stations in the Florida Keys has remained fairly constant through time: M. cavernosa 1.3 percent; S. siderea one percent; P. astroides about 0.7 percent; and C. 0.5 percent.
• The percent cover of octocorals averaged across all stations in the Florida Keys decreased steady from 1996 (12 percent) to 2000 (9 percent) than increased steadily to 2004 (14 percent). A decrease in coverage was observed from 2005 (14 percent) to 2006 (12 percent). 
• The percent cover of sponges averaged across all stations in the Florida Keys has decreased slightly throughout the course of the study from three percent in 1996 to twp percent in 2006.

Dry Tortugas

• From 1999 to 2006 the mean percent cover of stony corals per station decreased from 19 percent to nine percent. Three major decreases in stony coral cover were observed; from 2001 (17.5 percent) to 2002 (14 percent), from 2003 (13.5 percent) to 2004 (11.5 percent), and from 2005 (11.5 percent) to 2006 ( nine percent). 
• In the Dry Tortugas the five most abundant species throughout the course of the study have been Acropora cervicornis, Colpophyllia natans, M. annularis (species complex), M. cavernosa, and Siderastrea siderea.
• The mean percent cover of all stations in the Dry Tortugas of: A. cervicornis decreased steadily from 1999 (two percent) to 2004 (zero percent); C. natans decreased steadily from 1999 (two percent) to 2006 (one percent); M. annularis decreased drastically from 2001 (eight percent) to 2002 (5.5 percent) and again from 2005 (5.5 percent) to 2006 (four percent); M. cavernosa decreased steadily from 1999 (3.5 percent) to 2006 (two percent); S. siderea remained fairly constant through time (one percent).
• The percent cover of octocorals averaged across all stations in the Dry Tortugas was fairly constant from 1999 to 2003 (12 percent), but has decreased steady from 2003 to 2006 (eight percent).  
• The percent cover of sponges averaged across all stations in the Dry Tortugas has decreased steadily from 1999 (four percent) to 2006 (0.5 percent). 

• The area of clionid sponges averaged across all stations in the Florida Keys decreased from 2001 (7.1 centimeters squared/meters squared [cm²/m²]) to 2002 (4.4 cm²/m²) and then increased steadily to 2006 (5.7 cm²/m²).
• This trend mainly reflects a pattern observed at hardbottom habitats, whereas offshore deep, offshore shallow, and patch reef habitats have remained fairly constant through time.

Dry Tortugas 

• The area of clionid sponges averaged across all stations in the Dry Tortugas decreased from 2001 (12.3 centimeters squared/meters squared [cm²/m²]) to 2003 (5.9 cm²/m²) and then increased steadily to 2006 (13.6 cm²/m²).

The decreases in stony coral cover and species richness documented by the CREMP are evidence that multiple sources are creating stress upon corals at local, regional, and global scales and are continuing to have negative impacts on coral reefs in the Florida Keys National Marine Sanctuary.

Several major events have occurred that may have contributed to changes in coral reef condition. Declines in coral reef condition as reflected by changes in substrate cover and species richness coincided with a strong El Nino event in the late 1990's. The strong hurricane season in 2005 has also likely had some adverse impacts to Florida's coral habitats. The drastic decreases in clionid sponges observed in the early 2000's are consistent with a phytoplankton bloom, or algae bloom, that occurred on the west coast of Florida.

The CREMP 2007 Executive Summary was prepared by the Fish and Wildlife Research Institute

To obtain CREMP Executive Summaries from previous years or inquire about CREMP data please contact the Fish and Wildlife Research Institute corals group at Corals@MyFWC.com

Learn more about CREMP field and laboratory methods

Funding for CREMP has been provided by the Environmental Protection Agency and the National Oceanographic and Atmospheric Administration