2073_C002.fm Page 25 Friday, April 7, 2006 4:36 PM A Thousand Cuts? An Assessment of Small-Boat Grounding Damage to Shallow Corals of the Florida Keys Steven J Lutz CONTENTS 2.1 2.2 2.3 Introduction 25 Materials and Methods 26 Results 29 2.3.1 Geographic Distribution .29 2.3.2 Reef Sites 30 2.3.3 Head/Cluster Size .31 2.3.4 Depth of Head/Clusters 32 2.3.5 Mooring Buoys 32 2.4 Discussion and Conclusions 32 2.4.1 Geographic Distribution .33 2.4.2 Reef Size 33 2.4.3 Head/Cluster Size .33 2.4.4 Depth of Head/Clusters 33 2.4.5 Mooring Buoys 34 2.4.6 Impacts to Individual Coral Heads 34 2.4.7 Trend in High User Pressure 34 2.4.8 Management Considerations 34 2.5 Conclusion 36 Acknowledgments 36 References 36 2.1 INTRODUCTION For thousands of years coral reefs have survived natural impacts, such as storms, diseases, and predation What they cannot withstand is the combination of these natural impacts with severe or repeated anthropogenic damage, such as overfishing, sedimentation, and excess nutrients Reefs around Jamaica and San Andres have been devastated by this combination,1,2 and Florida reefs are widely reported to decline.3,4 Indeed, according to Wilkinson (1992),5 South Florida’s reefs are so “threatened” that they may disappear in 20 to 40 years Anthropogenic impacts to corals can be divided into direct and indirect effects.6 Indirect anthropogenic impacts throughout the Florida Keys, which include poor water quality and high 25 © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 26 Friday, April 7, 2006 4:36 PM 26 Coral Reef Restoration Handbook sedimentation rates, have received great attention from the scientific community.4,7–11 However, there is comparatively little information on direct anthropogenic damage, such as broken or overturned corals, on Florida coral reefs Much of this research has been related to the damage and rehabilitation of larger vessel groundings, which are highly visible and well documented.12–14 In contrast, little or no information on direct physical damage to corals caused by smaller vessels is available Previous studies and reports have noted this form of damage,12,15–20 also referred to as “orphan groundings” by Florida Keys National Marine Sanctuary staff However, the amount of damage caused by small vessels that are able to leave grounding incidents under their own power is unreported and may be vast; certainly, such incidents are much more numerous than large vessel groundings In the Florida Keys small-vessel grounding damage may be particularly widespread because many of the reefs that attract visitors have shallow-water corals Assessing the extent, amount, and impact of this form of anthropogenic damage to coral is essential for reef management This report is the first estimate of the geographic distribution and severity of small-vessel grounding damage on shallow-water massive corals of patch reefs throughout the Florida reef tract In this assay 315 shallow-water massive coral colonies from 49 reef sites within the Florida reef tract were examined for signs of boat grounding damage 2.2 MATERIALS AND METHODS This study was conducted from August 1996 to January 1997 on 49 reef areas with high-profile shallowwater coral heads or clusters of heads in the Florida Keys reef tract (Figure 2.1 and Figure 2.2) All but one of the reef sites surveyed were patch reefs; the exception was Carysfort Reef, a bank-barrier reef Patch reefs occur throughout the Florida reef tract They are particularly abundant in the waters off northern Elliot Key and south Key Largo, which include over 5000 patch reefs.21 Patch reefs typically occur in water to m deep and vary from 30 to 700 m in diameter.22 In the Florida Keys, the framework builder coral species of patch reefs include Siderastrea siderea, Diploria strigosa, D labyrinthiformis, Colpophyllia natans, Montastraea annularis, and M faveolata These corals have been termed boulder or massive corals.23 Montastraea annularis (senso lato) is particularly important as it has been described as a “keystone” species24 and can exhibit lateral growth as it approaches sea level This massive coral can be found growing in individual colonies, or heads, and in groups of amalgamated colonies, or clusters, growing together They can grow to be up to 100 m2 in area and have up to m of relief.25 Shallow-water massive coral heads and clusters of shallow massive coral heads are termed head/clusters for the purposes of this study The geographic location of each reef site was recorded with a hand-held global positioning system The exact depth and diameter of each coral head/cluster found within m of the surface was recorded for each reef site The survey depth of m was chosen to accommodate for tidal range (~1.5 m) and the maximum depth of typical hulls and/or propellers for small vessels (~1 m) The Northern Florida Keys tidal range was determined by inspection of tide tables.26,27 To account for tidal variation, all in situ depth measurements were standardized to depth below spring mean low water tide level Standardized depths ranged from 0.1 to 1.0 m According to vessel registration records, the majority of registered vessels in Miami-Dade and Monroe Counties are pleasure craft from 16 to 26 ft in length In the two counties, 36,312 such vessels were registered in 1994, accounting for 56% of all registered vessels.28 Miami-Dade and Monroe Counties are the closest counties to the northern Florida reef tract All of the corals in this survey were potentially susceptible to small-vessel grounding damage Reefs surveyed contained from one to 28 shallow-water head/clusters with the majority, 75%, containing from one to five head/clusters In total, 315 coral head/clusters were measured Head/clusters ranged in size from less than m (a singular head) to 18 m in diameter (a large cluster of amalgamated heads) The majority, 79%, were less than m in diameter Tidal range corrected depth of the top surfaces of head/clusters ranged from 25 cm to m in depth; 39% from to 0.25 m deep, 51% from 0.25 to 0.75 m deep, and 10% from 0.75 to m deep © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 27 Friday, April 7, 2006 4:36 PM A Thousand Cuts? 27 Bache Shoal patch reef Patch reef east of channel marker 11 Elli ot K ey South Florida Patch reef east of channel marker 13 Upper Keys Middle Keys Patch reefs southeast of channel marker 17 Caesar Creek N Patch reef east of channel marker 19 Lower Keys Patch reefs east of channel marker 21 Broad Creek Ha (ap wk C pro x nne rou l te) 25 20' Ke y La rgo East Basin Hill Shoals patch reefs Carysfort reef Basin Hill Shoals patch reefs 25 10' North Sound Land Cannon patch reef Mosquito Bank patch reefs South Sound Reef area with shallow head/cluster corals, undamaged Reef area with shallow head/cluster corals, damaged Dry Rocks patch reef 80 20' 80 10' FIGURE 2.1 Approximate locations of reef sites surveyed (North Florida reef tract) Of the 315 shallow-water head/clusters surveyed, 312 were Montastraea spp and three were S siderea Montastraea spp were identified according to the classifications of Weil and Knowlton (1994).29 Montastraea annularis and M faveolata were the only Montastraea spp recorded in the survey These two coral species commonly co-occur.30 © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 28 Friday, April 7, 2006 4:36 PM 28 Coral Reef Restoration Handbook South Florida A n Upper Keys Pl A Middle Keys B tio ta y Ke 25 58' an N Lower Keys w Ne Sn The Rocks patch reefs ak eC Land re ek Reef area with shallow head/ cluster corals, undamaged Reef area with shallow head/ cluster corals, damaged B 80 34' 81 28' Hawk Channel to the southeast 81 24' 24 38' Approach to Newfound Harbor Channel Newfound Harbor Keys Loggerhead Key Munson Heads patch reefs 24 36' Monkey Head patch reef Hawk Channel (approx route) FIGURE 2.2 Approximate locations of reef sites surveyed (Middle and South Florida reef tract) Although Acropora palmata is commonly found growing close to the surface, this coral was not included in the survey This coral species is particularly vulnerable to natural fragmentation during storms, which renders it difficult to distinguish between natural and anthropogenic damage.31,32 For underwater observations of direct physical damage a meter rule marked in 2- and 10-cm increments was used Damage was recorded in square centimeters and as the extent of surface area destroyed Two forms of physical damage were identified, collision damage and scarring damage Collision damage occurs when a coral is crushed and split by a vessel’s hull into multiple fragments Hull paint is often driven into the coral skeleton (Figure 2.3A and Figure 2.3G) Scarring damage, from boat propellers, tears off live coral, exposing the skeleton In propeller scarring, typical scarlike striations are seen (Figure 2.3B, Figure 2.3C, Figure 2.3D, Figure 2.3E, Figure 2.3F, and Figure 2.3I), and large fragments of coral can be chipped off (Figure 2.3E, Figure 2.3G, Figure 2.3H, and Figure 2.3I) Any damage whose source was not readily identifiable, for example when the surfaces were completely overgrown by turf algae and the corallites were not exposed or identifiable, was not included in the survey Statistical analysis was performed with the t-test and analysis of variance (ANOVA) where applicable © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 29 Friday, April 7, 2006 4:36 PM A Thousand Cuts? 29 (A) (C) (E) (B) (D) (F) FIGURE 2.3 Damage to various head/clusters A Patch reef southeast of channel marker 17, Biscayne National Park (BNP) Arrows indicate boat hull paint embedded in coral B Patch reef east of channel marker 21, BNP Arrow indicates small propeller scar C Mosquito Bank patch reef, John Pennekamp Coral Reef State Park (JPCRSP) D East Basin Hill Shoals patch reef, Florida Keys National Marine Sanctuary (FKNMS) E Basin Hill Shoals patch reef, JPCRSP F Patch reef area southeast of channel marker 17, BNP G Bache Shoal patch reef, BNP Arrows indicate crushed coral and boat hull paint H Munson Heads patch reef, FKNMS I East Basin Hill Shoals patch reef, FKNMS 2.3 RESULTS 2.3.1 GEOGRAPHIC DISTRIBUTION The results indicate that boat damage was widespread Most (57.1%) of the shallow-water reef sites surveyed showed signs of damage Of the 315 coral head/clusters found on those reefs, 79 (25%) had been damaged The total estimated area of destroyed coral found was 37,675 cm2 The area of damage to individual head/clusters ranged from 25 to 5800 cm2 Most damage found on © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 30 Friday, April 7, 2006 4:36 PM 30 Coral Reef Restoration Handbook (H) (G) (I) FIGURE 2.3 (Continued.) individual head/clusters was under 250 cm2 (illustrated in Table 2.1) Two reefs, Bache Shoal and Mosquito Bank (see Figure 2.1), had much more severe extent of damage than all other reef sites (3366 +/– 1570 cm2 (n = 6) on Bache Shoal and Mosquito Bank compared to 775 +/– 109 cm2 (n = 22) on all other reef sites, P = 0.0017) These two reefs accounted for 60.2% of all damage found (20,200 cm2) However the occurrence of damage incidents to head/clusters was not statistically significantly higher than at other reef sites (48.5 +/– 12.3% of head/clusters damaged on Bache Shoal and Mosquito Bank compared to 28.9 +/– 5.98% damaged on all other reef sites) 2.3.2 REEF SITES Reef sites surveyed contained from one to 28 shallow-water massive coral head/clusters The total amount of damage found on head/clusters per each reef site ranged from 25 to 10,925 cm2 coral destroyed For a comparative assessment of reef size damage, reef sites were divided into three size categories: small (zero to five head/clusters per reef); medium (six to 15 head/clusters per reef); TABLE 2.1 Percent of Damaged Head/Clusters by Area of Coral Destroyed Area of Coral Destroyed (cm2) ≤250 Percent of damaged head/clusters 251 to 500 501 to 1500 1501 to 3000 49.3 (n = 39) 24 (n = 19) 20.3 (n = 16) (n = 4) © 2006 by Taylor & Francis Group, LLC >3000 1.3 (n = 1) 2073_C002.fm Page 31 Friday, April 7, 2006 4:36 PM A Thousand Cuts? 31 TABLE 2.2 Reef Size and Damage Reef Size Class (Number of Head/Clusters) Small (1 to 5) Number of head/clusters per reef size class Percent of reefs damaged Mean area (cm2) of damage Mean number of damaged head/clusters Medium (6 to 15) Large (Over 15) 36 42.2 (n = 17) 421 +/− 117 (n = 36) 66.5 (n = 4) 700 +/− 375 (n = 6) 100 (n = 7) 2557 +/− 1414 (n = 7) 0.806 +/− 0.19 (n = 36) 2.5 +/− 1.147 (n = 6) 5.0 +/− 0.976 (n = 7) and large (>15 head/clusters per reef) (illustrated by Table 2.2) Damage among these reef size classes was distributed in the following proportions: 17 of the 36 (47.2%) small reefs, four of the six (66.6%) medium reefs, and seven of the seven (100%) large reefs had signs of damage A significant correlation was found between the number of shallow-water head/clusters per reef site and the amount of damage (mean total area in square centimeters per reef site): large reefs = 2557 +/– 1414 cm2 (n = 7); medium reefs = 700 +/– 375 cm2 (n = 6); small reefs = 421 +/– 117 cm2 (n = 36), P = 0.0055 A significant correlation was also found between the number of shallow-water head/clusters per reef site and the mean number of damaged head/clusters per reef site: (large reefs = 5.0 +/– 0.976 (n = 7); medium reefs = 2.5 +/– 1.147 (n = 6); small reefs = 0.806 +/– 0.19 (n = 36), P = 0.0001 (illustrated by Table 2.2) However, the number of shallow-water head/clusters per reef site did not appear to influence mean damage incidence or wound size: large reefs = 431 +/– 158 cm2 (n = 17); medium reefs = 218 +/– 68 cm2 (n = 4); small reefs = 528 +/– 125 cm2 (n = 7) (illustrated in Table 2.2) 2.3.3 HEAD/CLUSTER SIZE In order to determine whether head/cluster size influenced damage incidence, the 315 shallowwater massive coral head/clusters were divided into three size categories: small (< m diameter); medium (5 to 10 m diameter); and large (>10 m diameter) (illustrated in Table 2.3) No connection was found concerning damage incidence; 54 of the 240 (22.5%) small head/clusters, 17 of the 47 (36.1%) medium head/clusters, and eight of the 28 (28.5%) large head/clusters were damaged TABLE 2.3 Head/Cluster Size and Damage Head/Cluster Size Small (10 m Diameter) 240 47 28 22.5 (n = 54) 36.1 (n = 17) 28.5 (n = 8) 77 +/− 15 (n = 240) 282 +/− 131 (n = 47) 194 +/− 109 (n = 28) 2073_C002.fm Page 32 Friday, April 7, 2006 4:36 PM 32 Coral Reef Restoration Handbook TABLE 2.4 Depth of Head/Clusters and Damage Head/Cluster Depth to 0.3 m Number of head/clusters Percent damaged head/clusters Total area (cm2) of damage per head/cluster 0.4 to 0.6 m 0.7 to 1.0 m 123 30 (n = 37) 15,200 161 22.9 (n = 37) 21,775 31 16.1 (n = 5) 700 However, it was found that head/cluster diameter did influence the extent of damage (mean area in square centimeters per head/cluster size class) Medium and large head/clusters had more damage than did those in the small size class: small head/clusters = 77 +/– 15 cm2 (n = 240); medium head/clusters = 282 +/– 131 cm2 (n = 47); large head/clusters = 194 +/– 109 cm2 (n = 28), P = 0.0087 2.3.4 DEPTH OF HEAD/CLUSTERS The depth below mean low-water level of the top surfaces of the shallow-water head/clusters ranged from to 1.0 m In order to investigate the effect of depth on damage, the head/clusters were divided into three depth categories: to 0.3, 0.4 to 0.6, and 0.7 to 1.0 m depth (illustrated in Table 2.4) Damage incidence among the depth classes was distributed in the following proportions: 37 of the 123 (30%) 0- to 0.3-m deep head/clusters had signs of damage, as did 37 of the 161 (22.9%) 0.4to 0.6-m deep head/clusters and five of the 31 (16.1%) 0.7- to 1.0-m deep head/clusters Damage extent (total square centimeters of coral damaged per head/cluster) among the depth classes was distributed in the following proportions: 15,200 cm2 of the 0- to 0.3-m deep head/clusters coral was destroyed, 21,775 cm2 of the 0.4- to 0.7-m deep head/clusters coral was destroyed, and 700 cm2 of the 0.7- to 1.0-m deep head/clusters coral was destroyed The three depth categories not significantly differ from each other in either damage incidence or extent Neither, when damage occurs, does the depth of the top surfaces of shallow-water head/clusters affect the area of coral destroyed (mean area in square centimeters per damaged head/clusters) (0 to 0.3 m depth = 578 +/– 171 cm2 (n = 37); 0.4 to 0.6 m depth = 410 +/– 76 cm2 (n = 37); 0.7 to m depth = 140 +/– 67 cm2 (n = 5) 2.3.5 MOORING BUOYS Of the seven reef sites with mooring buoys that were surveyed, all but one had signs of damage Of the 42 reefs without mooring buoys surveyed, 22 had signs of damage However upon statistical evaluation, it was found that whether or not a reef had a mooring buoy did not affect the frequency of damage incidence (37.3 +/– 16.5% for reef sites with buoys [n = 7] compared to 30.3 +/– 5.9% for reef sites without buoys [n = 42]) Similarly, the extent of damage (mean area in square centimeters) found on reef sites is not affected by the presence or absence of mooring buoys (1415 +/– 485 cm2 [n = 22] on reefs without buoys compared to 1021 +/– 485 cm2 on reef sites with buoys [n = 6]) The presence or absence of mooring buoys on a reef did not significantly affect the degree of damage caused by small-boat groundings 2.4 DISCUSSION AND CONCLUSIONS Most damage found on individual head/clusters was under 250 cm2 Although this category of damage appears widespread throughout the study range, it does not suggest that it is a cause of any specific decline in the health of corals throughout the Florida Keys reef tract Additionally, the Florida Keys © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 33 Friday, April 7, 2006 4:36 PM A Thousand Cuts? 33 reef tract is a vast natural structure, most of which remains submerged out of smaller-vessel impact range during tidal fluctuations While the direct damage from small-boat contact does not pose a serious threat to its overall survival, the accumulated damage can degrade and destroy the structure of localized areas of shallow-water corals and coral clusters, demonstrating this impact’s importance to the health of localized head/clusters and contributing to the stresses these corals already experience 2.4.1 GEOGRAPHIC DISTRIBUTION The total amount of damage found at Bache Shoal and Mosqutio Bank was substantial, 60.2% of all damage found Indeed, these reefs show impact levels significantly higher than those of all other reefs Bache Shoal is one of the closest shallow reefs with mooring buoys to metropolitan Miami and is directly adjacent to a major boating channel, Hawk Channel (see Figure 2.1) To prevent vessel impacts, it is marked by a triangular reef warning tower and channel marker at its north tip It is significant to note that all shallow head/clusters surveyed at Bache Shoal were damaged, suggesting that its level of use or boat traffic (and related impacts) exceeds the safety methods used Mosquito Bank, located adjacent to Hawk Channel and directly in the line of boat traffic coming from slips on Key Largo and South Sound, also has a high percentage (42.6%) of head/clusters damaged, indicating a high level of use or traffic and the need for additional protection Results also suggest that these reef areas may be experiencing collisions by vessels that are larger and/or going much faster than on other reef sites Mosquito Bank’s high percentage of damage supports the Florida Department of Environmental Protection’s findings.33,34 Farther south, navigation channels and boater access may also play important roles in boat grounding damage, as The Rocks and Munson Heads are both adjacent to boating routes (see Figure 2.2) 2.4.2 REEF SIZE It appeared that reefs with five or more shallow-water head/clusters were more susceptible to smallboating damage than were reefs with fewer than five shallow-water head/clusters The more shallowwater head/clusters that a reef has, the more damage incidents or wounds, but the mean wound size remained the same, regardless of reef size Larger reefs may receive more damage because the likelihood of collision with a larger reef area is greater, even though smaller reefs are more numerous However, smaller reefs may also not be as attractive to small-boat traffic from tourists because they have less relief, smaller associated fish populations, and a smaller amount of live coral 2.4.3 HEAD/CLUSTER SIZE It appeared that the larger, in diameter, a shallow-water head/cluster, the more damage, but the frequency of damage remains the same, regardless of diameter It is possible that small-vessel impact damage is infrequent overall and occurs at random However, when such damage occurs, the larger in diameter a head/cluster, the greater the chance that a single damage incident will result in substantial damage 2.4.4 DEPTH OF HEAD/CLUSTERS It was interesting to find that within the 1-m depth range from spring low tide, the depth of the top surfaces of shallow-water head/clusters did not significantly influence either the degree or extent of damage caused by small-boat groundings Therefore, all corals within a 1-m depth range from spring low tide are susceptible to small-vessel grounding damage If the sample depth range of this survey had been extended to or m, frequency and extent of damage might have significantly correlated with depth; this, however, would have greatly lengthened survey time © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 34 Friday, April 7, 2006 4:36 PM 34 Coral Reef Restoration Handbook 2.4.5 MOORING BUOYS One would expect to find higher levels of damage to shallow-water massive corals at reef sites with mooring buoys since mooring buoys tend to attract more recreational boaters However, the presence or absence of mooring buoys on a reef did not significantly alter the frequency or extent of damage caused by small-boat groundings More recreational boaters may be drawn to reefs with mooring buoys, but they appear to avoid any significant additional damage to shallow-water massive corals 2.4.6 IMPACTS TO INDIVIDUAL CORAL HEADS It might be expected that small-vessel groundings are an important cause of damage on localized cluster-heads Because boating damage tends to occur on the top surfaces of coral colonies, their detrimental effects may be more substantial than those of other types of lesions Damage caused by storm rubble, in contrast, tends to occur more often on the sides of large colonies, rather than the tops Large lesions may not completely heal, although partial regeneration may occur at the edges.35,36 It has been found that within a week of a scarring event, filamentous algae colonize exposed skeleton and inhibit coral regeneration Turf algae or other reef organisms may be well established by the time the healing margin of live coral reaches them The encrustation of some organisms (e.g., boring sponges, encrusting zoanthids) can lead to further bioerosion of the colony Meesters (1995),36 in a study regarding damage and regeneration on scleractinian corals, showed that many lesions on the top surfaces of bleached coral colonies enlarged to numerous times their initial size, occasionally resulting in the death of the entire colony Indeed, it appears that M annularis may be very sensitive to bleaching.36–38 Herbivorous fish pecking at the edge of a scar can consume turf algae and coral at the same time.39 In addition, coral scarring may affect the total health of the colony by forcing the coral to reallocate resources to regeneration, and away from growth, reproduction, and combating disease Additionally, the cumulative effect of this form of damage to individual coral heads may have negative tourism consequences As impacts are to the shallowest and most accessible area of reefs, they are easily within snorkeling range Figure 2.3 clearly illustrates the diminished aesthetic value of damaged coral heads 2.4.7 TREND IN HIGH USER PRESSURE The increasing trend of recreational use of South Florida marine habitat is evidenced by the 40.8% increase in registered vessels in 10 years in Miami-Dade and Monroe Counties (from 62,274 in 1993 to 87,699 in 2003).40,41 Indeed, it appears almost certain that continued high user pressure on the most frequented reefs will, in a short time, degrade the aesthetic and recreational qualities of the reefs Additionally, the continued high and relentless incidence of damage to these colonies will result in loss of the larger and older massive coral colonies For these reasons it is imperative that management deal with the small-boat problem as a priority 2.4.8 MANAGEMENT CONSIDERATIONS This study indicates that the cumulative effect of small-vessel groundings presents a serious threat to localized coral eco-health and contributes significantly to other reef stresses Marine parks and management in the Florida Keys are charged with the protection of the natural resources, especially coral reefs, under their jurisdictions Table 2.5 illustrates coral damage on shallow water reef sites by management authority for reefs surveyed A comprehensive management plan is needed in order to reduce the number of small-vessel groundings Management’s options for minimizing this type of anthropogenic damage would vary according to available manpower and funds In order to present a scientifically based management plan, the author suggests that, first, localized shallow-water reef areas with high levels of user impact must be identified For “real time” observations, this type of survey should be carried out on an annual basis, © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 35 Friday, April 7, 2006 4:36 PM A Thousand Cuts? 35 TABLE 2.5 Reef Sites Surveyed and Management Authority Management Authority Biscayne National Park John Pennekamp Coral Reef State Park Florida Keys National Marine Sanctuary Percentage of Shallow Reef Sites Surveyed 22 10 17 Percentage of Shallow Reef Sites Surveyed with Damage 54.5 70 52.9 to gauge the direction of user pressure and to determine the effects of preservation and restoration actions The particular criteria for identifying such reefs should include an estimate of the percentage of impacted shallow-water coral colonies Special attention should be placed on reefs with over 15 shallow-water head/clusters, reefs with head/clusters over m in diameter, and reefs close to navigation channels and popular marinas These reefs are especially prone to this type of impact Severity of damage incidence can be estimated from measurements of the area of coral destroyed, as laid out in this chapter Reefs with a high percentage of shallow-water corals damaged or colonies with severe damage should be designated for immediate prevention and restoration action As a result of such surveys, the management options for damage prevention would depend upon the severity of impact and could include the following: The placement of additional “shallow reef ” markers or other navigational beacons highlighting shallow corals prone to this type of impact The targeted placement of additional mooring buoys (There are currently approximately 40 reef sites with mooring buoys throughout the Florida Keys.) The establishment of small targeted preservation zones, which would restrict a certain use (i.e., boating, diving, or fishing activities) and thereby lessen user pressure on a particularly stressed and sensitive ecosystem The establishment of critical zones, where all recreational and commercial access is prohibited (Currently, approximately 6% of the Florida Keys National Marine Sanctuary is set aside as fully protected zones known as ecological reserves, sanctuary preservation areas, and special use areas.) Education would also play an important part in reef preservation Marinas and boat rental shops close to damaged reefs could be targeted for educational materials, and boat pilot training programs highlighting this type of problem could be planned Advertising fines could help make boaters more cautious while boating in shallow reef areas Individual coral head/cluster restoration options would depend upon the severity of impact and could include the following: No action taken: the wound size is so minimal that the coral’s natural healing process will suffice to restore the damage, or restoration action may lead to further direct physical damage to corals and surrounding benthos Stabilization and restructuring of unconsolidated coral fragments in a wound area, as required, in order to mimic the look and function (biological and aesthetic) of the original ecosystem The removal of bioeroding and competing organisms and/or the possible transplantation of coral in an unnatural wound area, giving the natural healing process of damaged coral colonies a “boost” (only feasible on the most severe of damage incidents) © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 36 Friday, April 7, 2006 4:36 PM 36 Coral Reef Restoration Handbook 2.5 CONCLUSION In conclusion, this study shows that small-boat groundings on reef areas present a serious widespread negative impact to localized coral eco-health, especially on larger reef areas and to massive corals, and make a significant contribution to the stresses and pressures that corals already endure throughout the Florida Keys reef tract (including bleaching, disease, pollution, large-vessel groundings, high use, etc.) It is imperative that small-vessel grounding damage be minimized This distinct category of anthropogenic damage is a major insufficiently recognized negative impact to highly visited coral reef areas that must be dealt with in any scientifically based management plan ACKNOWLEDGMENTS The author thanks the Florida Keys National Marine Sanctuary, Biscayne National Park, and John Pennekamp Coral Reef State Park for their assistance, advice, and permission to conduct studies under their jurisdictions and R.N Ginsburg for project guidance, comments, and review This project was funded by the Filipacchi Hachette Foundation as part of the International Year of the Reef Program (IYOR) and produced a masters thesis for the Division of Marine Affairs and Policy, University of Miami, Rosenstiel School of Marine and Atmospheric Science (RSMAS) REFERENCES Hughes, T., et al 1985 Mass mortality of the echinoid Diadema antilarum phlippi in Jamaica Bull Mar Sci 36:377–384 Hallock, P., et al 1993 Coral reef decline National Geographic Research & Exploration 9:385–387 Porter, J.W., Meier, O.W 1992 Quantification of loss and change in Florida reef coral populations Amer Zool 32:625–640 La Pointe, B 1994 Phosphorus inputs and eutrophication on the Florida reef tract In: Ginsburg, R.N (ed.) 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Poster presented at the South Florida Restoration Science Forum, Boca Raton, FL Shinn, E.A., Lidz, B.H., Hudson, J.H., Kindinger, J.L., Halley R.B 1989 Reefs of Florida and the Dry Tortugas: IGC Field Trip Guide T176 Washington, DC: American Geophysical Union, p 53 10 Cole, J 1990 The state of our seas Florida Keys Magazine 13(6):20–24 11 Dustan, P., Halas, J.C 1987 Changes to the reef-coral community of Carysfort Reef, Key Largo, Florida: 1974 to 1982 Coral Reefs 6:91–106 12 Causey, B.D 1990 Biological assessments of damage to coral reefs following physical impacts resulting from various sources, including boat and ship groundings In: Jaap, W.C (ed.) Proc Am Acad Underwater Sci., 10th Annual Diving Symposium, St Petersburg, Florida, pp 49–57 13 Wheaton, J.L., Jaap, W.C., Kojis, B.L., Schmahl, G.P., Ballantine, D.L., McKenna, J.E 1992 Transplanting organisms on a damaged reef at Pulaski Shoal, Ft Jefferson National Monument, Dry Tortugas, FL (abstract) Bull Mar Sci 54:1087–1088 14 Miller, S.L., McFall, G.B., Hulbert, A.W 1993 Guidelines and Recommendations for Coral Reef Restoration in the Florida Keys National Marine Sanctuary, workshop report NOAA, p 38 15 Dustan, P 1977 Besieged reefs of the Florida Keys Nat His 86:73–76 © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 37 Wednesday, April 12, 2006 10:23 AM A Thousand Cuts? 37 16 Hudson, J.H., Goodwin, W.B 2001 Assessment of vessel grounding injury to coral reef and seagrass habitats in the Florida Keys National Marine Sanctuary, Florida: protocols and methods Bull Mar Sci 69:509–516 17 Jaap, W.C 1999 Coral Reefs Presentation to the Florida Keys Carrying Capacity Study Ecosystems Workshop, Marathon, FL, July 7–8, 1999 18 Tilmant, J.T 1987 Impacts of recreational activities on coral reefs In: Salvat, B (ed.) Human Impacts of Recreational Activities on Coral Reefs: Facts and Recommendations Antenne Museum E.P.H.E French Polynesia: pp 195–209 19 Tilmant, J.T., Schmale, G.P 1981 A comparative analysis of coral damage on recreationally used reefs within Biscayne National Park, Florida In: Proc 4th Int Coral Reef Symp Manila, 1:187–192 20 Voss, G 1983 An Environmental Assessment of the John Pennekamp Coral Reef State Park and the Key Largo Coral Reef Marine Sanctuary (unpublished report) 21 Marszalek, D., Babashoff, G., Noel, M., Worley, P 1977 Reef distribution in south Florida Proc 3rd Int Coral Reef Symp., Miami, FL 2:233–230 22 Jaap, W.C., Hallock, P 1990 Coral reefs In Myers, R.N and Ewel, J.J (ed.) Ecosystems of Florida University of Central Florida Press: pp 574–616 23 Humann, P 1993 Reef Coral Identification Paramount Miller Graphics, Inc., Jacksonville, FL 24 Hudson, H 1981 Growth Rates in M annularis: a record of environmental change in Key Largo Coral Reef Marine Sanctuary, FL, Bull Mar Sci., 31:444–459 25 Ginsburg, R.N., Shinn, E.A 1993 Preferential distribution of reefs in the Florida reef tract: the past is key to the present In: Ginsburg, R.N (ed.) Global Aspects of Coral Reefs, Health Hazards and History University of Miami, FL, pp 21–26 26 International Marine 1996 Tide Tables: High and Low Water Predictions, East Coast of North and South America Camden, ME 27 International Marine 1997 Tide Tables: High and Low Water Predictions, East Coast of North and South America Camden, ME 28 Boating Research Center 1994 Atlas of Boats, Florida, 1994 University of Miami Rosenstiel School of Marine and Atmospheric Science 29 Weil, E., Knowlton, N., 1994 A multi-character analysis of the Caribbean coral Montastraea annularis and its two sibling species, M faveolata and M franksi Bull Mar Sci 55:151–175 30 Knowlton, N., Mate, J.L., Guzman, H.M., Rowan, R., Jara, J 1997 Direct evidence for reproductive isolation among three species of the Montastraea annularis complex in Central America (Panama and Honduras) Mar Bio 127:705–711 31 Fong, P., Lirman, D 1995 Hurricanes cause population expansion of the branching coral Acropora palmata (Scleractinia): wound healing and growth patterns of asexual recruits Mar Ecol 16:317–335 32 Highsmith, R.C 1982 Reproduction by fragmentation in corals Mar Ecol (Prog Ser.); vol 7, no 2: pp 207–266 33 Deaton, A.S., Duquesnel, J.G 1996 Marine Research and Resource Monitoring in John Pennekamp Coral Reef State Park, 1995 Update Report, Update to Section I, Part C Boat Grounding Assessments Florida Dept of Environmental Protection, Division of Recreation and Parks, District Administration, pp 1–12 34 Skinner, R.H., Deaton, A.S., Duquesenel, J.G 1993 Marine Research and Resource Monitoring in John Pennekamp Coral Reef State Park Florida Dept of Environmental Protection (eds.), Division of Recreation and Parks, Region VII Administration: pp 9–35 35 Bak, R., Brouns, J., Heys, F 1977 Regeneration and aspects of spatial competition in the scleractinian corals Agaricia agaricites and Montastrea annularis In: Proc 3rd Int Coral Reef Symp Miami, FL, pp 143–149 36 Meesters, E.H 1995 Effects of coral bleaching on tissue regeneration potential and colony survival In Meesters, E.H.: The Function of Damage and Regeneration in the Ecology of Reef-Building Corals (Scleractinia) Netherlands Institute for Sea Research (thesis publication): pp 27–42 37 Goreau, T.J., Macfarlane, A.H 1990 Reduced growth rate of Montastrea annularis following the 1987–1988 coral bleaching event Coral Reefs 8:211–215 38 Szmant, A.M., Gassman, N.J 1990 The effects of prolonged bleaching on the tissue biomass and reproduction of the reef coral Montastraea annularis Coral Reefs 8:217–224 39 Glynn, P.W 1990 Coral mortality and disturbances to coral reefs in the tropical eastern Pacific In Glynn, P.W (ed.) Global Ecological Consequences of the 1982–83 El Nino–Southern Oscillation © 2006 by Taylor & Francis Group, LLC 2073_C002.fm Page 38 Friday, April 7, 2006 4:36 PM 38 Coral Reef Restoration Handbook 40 Boating Research Center 1994 Atlas of Boats, Dade County, Florida, 1993 University of Miami Rosenstiel School of Marine and Atmospheric Science 41 Florida Fish and Wildlife Conservation Commission 2004 2003 Boating Accident Statistical Report Retrieved October 2004 Available online at: http://www.floridaconservation.org/law/boating/2003 stats/2003StatBook1.pdf © 2006 by Taylor & Francis Group, LLC ... 28 .5 (n = 8) 77 +/− 15 (n = 24 0) 28 2 +/− 131 (n = 47) 194 +/− 109 (n = 28 ) 20 73_C0 02. fm Page 32 Friday, April 7, 20 06 4:36 PM 32 Coral Reef Restoration Handbook TABLE 2. 4 Depth of Head/Clusters... proportions: 15 ,20 0 cm2 of the 0- to 0.3-m deep head/clusters coral was destroyed, 21 ,775 cm2 of the 0. 4- to 0.7-m deep head/clusters coral was destroyed, and 700 cm2 of the 0. 7- to 1.0-m deep head/clusters... Francis Group, LLC 20 73_C0 02. fm Page 36 Friday, April 7, 20 06 4:36 PM 36 Coral Reef Restoration Handbook 2. 5 CONCLUSION In conclusion, this study shows that small-boat groundings on reef areas present