Report Prepared for Wildlife Trust by Lisa Carne
Survey team: Lisa Carne, Burton Shank, Linda Garcia, & Louis Godfrey
Project Funded by Disney Wildlife Conservation Fund
Project Coordinator: Nicole Auil

The MesoAmerican Barrier Reef Systems (MBRS) Project was implemented in Belize in 2003. It was designed to give regional consistency to monitoring efforts in Mexico, Belize, Guatemala and Honduras. The Synoptic Monitoring Program (SMP) was written using a combination of existing protocols and data have been collected since 2004 in seven sites in Belize, and three each in Mexico, and Guatemala/Honduras (combined). The data from 2004 and 2005 have been analyzed, recently released, and serve as a baseline for local monitoring results (Salgado et al. 2006).

Blue Field Range is approximately 15miles east of Southern Lagoon, Wildlife Trust’s primary research site. It has three small islands, and is approximately 2.5 miles west of the barrier reef; Middle Long Caye is northward and Alligator Caye southward. The MBRS SMP was used to monitor Blue Field Range reef sites for multiple reasons: it compliments and adds to the existing national data set as the closest MBRS sites are South Water Caye and Turneffe Atoll, and it documents and describes an important watershed area (Gales Point/Manatee River) and manatee reef habitat. Two deep (8-18m) fore reef sites and two back reef sites were surveyed using the MBRS Category 1 monitoring methods for corals, algae and fish (Almada-Villela et al. 2003) (http://www.mbrs.org.bz).

Summary of Results

I. Benthic

The average live coral cover for all four sites at Blue Field Range (BFR) is 26%. The average deep fore reef live coral cover is 20% and the average back reef live coral cover is 33%. Dead coral makes up an average of 8% of the benthic composition at all four sites: 7% dead coral on the fore reef and 9% on the back reef. However 61% of all corals measured (n=162) had partial old mortality. The average macro algae cover (which includes all fleshy algae and halimeda spp. and turf, to compare to MBRS results*) is 24% at Blue Field Range sites: 40% on the fore reef and 9% on the back reef.

Ia. Species Richness of Scleractinian corals
The average number species of hard corals at the four Blue Field Range sites is thirteen: 17 on the fore reef (mean) and 10 on the back reef sites (mean). The MBRS regional average is 11 hard coral species. In Belize, the only deep fore reef site with more hard coral species is South Water Caye (>20).

Click here to see Table 1

Ib. Coral Health (Size, Disease, Bleaching)
The mean maximum diameter for all corals sampled at all four sites is 54cm (n=162), compared to the MBRS regional results of 34cm. The fore reef average maximum diameter is only 24cm (n=96) versus 84 cm (average, n=66)) on the back reef sites. The fore reef results at BFR are below the MBRS Regional results (30cm) but the BFR back reef mean maximum diameter is much higher than the MBRS Regional results (40cm). However McField (2007) list a fore reef mean maximum diameter of 55cm and list anything under this value as “Red Flagged”; a warning. The average height for all corals sampled (includes plate corals) is 22cm, just above the MBRS regional results (21cm). The fore reef average height is 12 cm (MBRS=17cm) while the back reef average height is 31cm (MBRS=26cm).

On the fore reef at Blue Field Range 58 of the 96 corals measured (60%) had partial mortality. The MBRS Regional results for partial mortality on the fore reef are much lower: 35%. On the back reef 41 of 66 (62%) corals measured had partial (old) mortality, compared to the MBRS Regional results for this habitat of 45%. The amount of the coral colony that is dead averaged out to 34% on the fore reef and 40% on the back reef.

Four Acropora cervicornis colonies were recorded along the transect line with white band disease at one back reef site, giving a total of three percentage (3%) of colonies with disease (n=162) at Blue Field Range.

No bleaching was observed on any corals under the transect lines.

II. Reef Fish

IIa. Adult Fish Density
Both fore reef sites have an adult fish density of 45fish/100m2, well above the MBRS regional average of 33fish/100m2 (deep fore reef habitat). ALIBack has an adult fish density of 83individuals/100m2 and BFR2 has 47fish/100m2. Both are above the MBRS regional average (29fish/100m2) for back reef sites. All Blue Field Range Sites combined (across habitats) have an average adult fish density of 55fish/100m2, well above the Belizean MBRS National (across all habitats) results of 32fish/100m2. The only Belizean site with a comparable adult fish density (57ind/100m2) is Hol Chan, and that site has had protection for decades. Table 3a shows the adult fish density at BFR sites compared to MBRS regional and national averages. For a complete list of adult fish species surveyed see Appendix p. ii.

IIb. Adult Fish Density by Family
Lutjanidae (snappers), Scaridae (parrotfishes) and Haemulidae (grunts) are the most abundant families in both habitats (deep fore reef and back reef) surveyed at Blue Field Range.

IIc. Fish Size Structure/Distribution
The most abundant size category of fishes in the Blue Field Range back reef habitat is 11-20cm, which is comparable to the MBRS Regional results for back reef habitat. However the BFR fore reef habitat contained the most fishes in the smallest category (6-10cm) which differs from the MBRS regional data for the deep fore reef habitat (the highest numbers were in the 11-20cm category for the regional deep fore reef habitat). Coupled with the small amount of any fish over 30 cm in either habitat, this is a clear indication of overfishing.

Introduction/Site Selection

Blue Field Range is located approximately midway between Belize City and Dangriga, and approximately 12 miles due East of Manatee River (see map). No MBRS surveys have been done in this area; the closest sites surveyed in 2004/5 were Turneffe Atoll to the East and South Water Caye to the South. Blue Field Range and Alligator Caye are mostly mangrove cayes, with little fringing reef (based on Manta Tows performed in 2006 by Wildlife Trust).

Click here to see the MBRS Survey Sites, including Wildlife Trust sites at Blue Field Range (BFR) and Alligator Caye

Conclusions/Recommendations

These initial surveys at Blue Field Range begin to fill in a gap in the National reef monitoring efforts. MBRS surveys have been completed at South Water Caye and Turneffe, and some AGRRA surveys have been conducted 8-12 miles south of Blue Field range. While the fore reef sites at Blue Field range are fairly representative of deep fore reef habitat in other parts of Belize, the back reef sites at Blue Field Range are exceptional for their live coral cover and fish density - even more so considering theses sites are not in any marine reserve. The coastal area to the West of Blue Field Range is as yet undeveloped compared to the Northern and Southern regions of Belize, and one must suspect this to be the reason for the relative excellent health in the back reef habitat here. Additionally there is little to no tourism traffic here (bare boat charters perhaps). However the lack of any large fish (as elsewhere in Belize) reflect the incredible fishing pressure that has yet to be addressed nationally.

Both back reef sites have exceptional live cover of two endangered coral species: Acropora palmata (elkhorn coral) and A. cervicornis (staghorn coral). These sites should be monitored closely on a regular basis, especially considering the incidence of disease at both sites: is it just beginning to take effect? Will it eventually kill all of the coral as it has in other areas?

The back reef at one site was covered in Iciligorgia schrammi (deep water sea fan) a species normally found in deep fore reef habitats. And several C. aculeatus (longsnout butterflyfish) were recorded at the second back reef site, a fish species also normally found on the deep fore reef.

Ideally, additional survey sites should be included in this area: monitoring around Rendezvous and Goff’s Caye should be included as a comparison for tourism impact, and further sites should be explored to the south to see how far this exceptional back reef healthy habitat extends. No real statistics were performed for this report as there were only two data sets for each habitat: additional sites will make the habitat results more meaningful.

Since Blue Field Range is manatee habitat, seagrass, mangrove and water quality monitoring should also be included in this area: limited data is currently available for this central region of Belize. Additionally mangrove and seagrass are crucial habitats for many commercial species of fish and the juvenile fish surveys should be concentrated in these habitats, as opposed to reef habitats.

Since reef monitoring is costly and time consuming, not all objectives can be achieved. However due to the exceptional quality of the back reef sites at Blue Field Range, the lack of any other data from this area, the as-yet undeveloped coastline and the lack of any marine protection, expanded and continued monitoring here is crucial. If it can be shown that the healthy back reef environment (and potentially healthy sea grass/juvenile commercial species habitat) is directly linked to the lack of coastal development (by exploring sites further south and comparing to data from sites in front of heavily developed coastlines), this information would be valuable to many. It might also redefine how we think of marine protected areas in terms of what are the most important parameters to control.

The Belizean Fisheries Department, Department of Environment, Department of Natural Resources and PACT would all benefit from further data gleaned from this area. Monitoring here also compliments and adds to both MBRS and AGRRA data set for Belize.

REFERENCES

Almada-Villela, P. C., P. F. Sale, G. Gold-Bouchot, B. Kjerkve. 2003. Manual of methods for the MBRS synoptic monitoring program. Selected methods for monitoring physical and biological parameters for use in the Mesoamerican region. Mesoamerica Barrier Reef Systems Project. Belize City. 149 pp.

Humann, P. 2002. Reef Coral Identification. New Word Publications, Inc.

Humann, P. 2002. Reef Fish Identification. New Word Publications, Inc.

McField, M. and P. Richards Kramer. 2007. Healthy Reefs for Healthy People: A Guide to Indicators of Reef Health and Social Well-being in the Mesoamerican Reef Region. With contributions by M. Gorrez and M. McPherson. 208 pp. Available at http://www.healthyreefs.org/

McField, M. 2001. The Influences of Disturbances and Management on Coral reef Community Structure in Belize. PhD Dissertation. College of Marine Science, University of South Florida. St. Petersburg, Florida, USA.