Proceedings of the 11th International Coral Reef Symposium, Ft. Lauderdale, Florida, 7-11 July 2008 Session number 18

Demographic comparison of threatened Elkhorn coral, Acropora palmata, in the Caribbean: A case study in successful volunteer partnerships in a regional-scale monitoring program.

K.L. Kramer1,2, D.E. Williams2, M.W. Miller3, C. Bégin4, J. Fry4, A. Valdivia2

1) National Park Service, PACN Inventory and Monitoring, P.O. Box 52, Hawaii NP, HI 96718 2) University of Miami, CIMAS, 4600 Rickenbacker Cswy, Miami, FL 33149 3) NOAA Southeast Fisheries Science Center, 75 Virginia Beach Dr., Miami, FL 33149 4) SeaMester, P.O. Box 5477, Sarasota, FL, 34277

Abstract. Due to severe and ongoing population declines, Acropora palmata received US federally threatened status in 2006. NOAA has since released a protocol for demographic monitoring of this genus in order to assess population status, and to encourage monitoring partnerships throughout the Caribbean (Williams et al 2006). In 2006, NOAA partnered with the SeaMester program to include monitoring sites along their sailing routes, including the British Virgin Islands (BVI), Bequia (St. Vincent Grenadines), and Green Island (Antigua). Monitoring data collected by the SeaMester program in the BVI are presented here, along with NOAA monitoring data from Curacao (Netherlands Antilles). Six fixed A. palmata monitoring plots were established in BVI, and 9 were established in Curacao. Within these plots, 12-15 randomly selected colonies have been measured annually and examined for signs of disease, predation, and other notable conditions. Live area index (LAI), and white syndromes, snail predation, and damselfish territory prevalence were statistically compared between the two regions. The relatively user-friendly protocol coupled with basic field trainings with partners allowed for substantial spatial expansion of this monitoring program. This broader monitoring coverage is needed to guide prioritized Caribbean-wide management based on observed population condition and resilience.

Key words: Acropora, demographic monitoring, Coralliophila, Stegastes.

Introduction designed to promote collaborative monitoring The elkhorn coral, Acropora palmata, is a spectacular partnerships throughout the Caribbean. shallow-water branching coral species that offers structural framework, protective habitat, and tourist- Material and Methods appeal to coral reef ecosystems. Like many other In January 2006, education staff from the SeaMester coral reef species, disease and bleaching events, program volunteered to participate in monitoring hurricanes, and stressors associated with coastal efforts along its Caribbean sailing route, which development have driven dramatic population provided a unique opportunity to address the declines over the past 40 years (Gladfelter 1982, significant gap in A. palmata monitoring and research Nagelkerken and Nagelkerken 2004, Boulon et al in the eastern Caribbean. After receiving field training 2005). and guidance from the protocol authors, staff and In response, A. palmata and congener, staghorn students from the SeaMester program initiated A. coral (A. cervicornis), were listed as threatened under palmata monitoring off Virgin Gorda and West Dog the US Endangered Species Act (ESA) in May 2006 Island (British Virgin Islands), Bequia (St. Vincent (NMFS 2006). To satisfy the ESA mandate for Grenadines), and Green Island (Antigua). These regular status updates, the National Oceanographic complement existing NOAA monitoring locations in and Atmospheric Administration (NOAA) released a the Florida Keys, Puerto Rico, Navassa Island, and protocol for Acropora spp. demographic monitoring Curacao (Netherlands Antilles) (See Fig. 1). Results (Williams et al. 2006). The protocol aims to directly presented here will focus on monitoring efforts in document population status, and to apply findings to Curacao and the BVI. management activities. Also, the protocol was

765 territory prevalence (defined by live tissue ‘chimney’ structures topped with algal tufts (Fig. 2).

Figure 1: Current A. palmata demographic monitoring sites.

Detailed monitoring methods are available in Figure 2: A colony from a Curacao monitoring plot at site Williams et al. (2006). In each monitoring region, we ‘SeaAqrm’ impacted by an extensive three-spot damselfish (S. located 2-3 reef areas with moderately dense A. planifrons) territory. S. planifrons repeatedly bites areas of live palmata colonies (avoiding thickets and isolated coral tissue, which heal and overtime become chimney-like structures topped with fleshy macroalgae. colonies). In these areas, we haphazardly established three 7m radius permanent monitoring plots, and Datasets were first tested for normality and within in each plot, 12-15 colonies were randomly homogeneity of variance (Levene’s test), and if selected for tagging and detailed monitoring. Each needed, transformed (log , square-root) to correct for tagged colony has been annually measured, and 10 failed assumptions. Usable datasets were statistically examined for signs of disease, predation, bleaching, compared using a repeated measure (annual) fragmentation, growth anomalies and other notable hierarchical design ANOVA with survey plot nested conditions. within site and region. Using size measurements, we calculated a live area index (LAI) for each tagged colony, where: LAI= Results ((length x width x height)/3)2 x % live. This served as Live Area Index (LAI): Colony assemblages in the an index (not a direct estimate) of change in colony BVI and Curacao were very distinct, which was live tissue coverage. Importantly, LAI generally reflected in the live area index (LAI). A typical underestimates actual surface area, and this colony in the monitored areas of Curacao was underestimate increases with colony complexity. relatively large, with many long branches, and low When additional resources were available, we also partial mortality (resulting in a high LAI). A typical conducted annual total live tissue inventories colony in monitored areas of the BVI was small and (including recruitment) within each plot, genotype mostly encrusting with sometimes a few short analysis, growth measurements, and exploratory branches, and a moderate level of partial mortality regional mapping. (resulting in a low LAI). LAI varied significantly by Datasets and photographs were received within one region, and was twice as high for Curacao plots (Fig. month of each monitoring event conducted by 3). LAI increased slightly at all plots between 2006 SeaMester staff and students. NOAA staff regularly and 2007. addressed field questions, and datasets were quality- Disease Prevalence: White syndrome (WPx, WBD, assured by verifying observations with colony RTL) prevalence varied significantly by year and by photographs and through discussion with the region (Fig. 4). In 2007, white syndromes affected observers. 23.9-56.9% of monitored colonies in Curacao, We compared Curacao and BVI datasets for: a) compared to 19.4-36.0% in 2006, and to 0-2.8% for white syndrome prevalence (including white-band the BVI in 2006. By 2008, white syndrome disease (WBD), white pox (WPx), and rapid tissue prevalence in Curacao fell to 14.6-29.3% of colonies loss (RTL)), b) average colony live area index (LAI), affected, and healing lesions were frequently c) snail (Coralliophila abbreviata) predation observed. prevalence (defined by regions of exposed, clean white skeleton along the colony live tissue edges), and d) three-spot (Stegastes planifrons) damselfish

766 in 2006-2007 (+ affecting wh of Figure 4:Meanprevalence (+ index (LAI) colony livearea Figure 3:Mean factor. significant *Indicates astatistically palmata grazing by thecoral-eatingsnail, which rangedfrom 19.4-33.7%) (Fig. 2,Fig.6). colonies affected, except Curacao site ‘SeaAqrm,’ at all sites (ranging from 0-9.9% of monitored low wasgenerally (Fig. 6).Prevalence site monitoring planifrons vary significantly by year, region or site (Fig. 5). Predation prevalence washighly variable, and did not affected in Curacao, a ranged from 2.1-22.2% of monitored colonies Snail Predation: Predation: Snail Damselfish Territories: Damselfish

% Live colonies affected 100 LAI (m2) 20 40 60 80 10 15 20 0 0 5 colonies inCuracaoandtheBVI20062007. A. palmata ) territories varied significantly by CURACAO CURACAO 1 SE). *Indicates a statistically significant factor. factor. significant *Indicatesastatistically 1 SE). Sea Aqrm Sea Aqrm 2007 2006 colonies in Curacaoin2006-2008 and the BVI 2008 2008 2007 2006

Blau Baii Blau Baii The prevalence oflivetissue

nd 0-15.9% in the BVI. BVI. inthe nd 0-15.9% Boca SM Boca SM Three-spot damselfish ( ite syndromesite (WBD, WPx, RTL) Plot: p=0.031 (df=10) Site: p=0.335 (df=3) Region: Year: Site: p=0.057 (df=3) p=0.057 Site: (df=1) p=0.000* Region: Year:

p=0.286 (df=1) p=0.286 p=0.002*(df=1) p=0.035* (df=2) p=0.035*

Mtn Pt BVI Mtn Pt BVI C. abbreviata,

W Dog SE) 1 for W Dog

767 S. A. A.

2006-2007 (+ abbreviata Figure 5: Mean prevalence (% live (% prevalence Figure 5:Mean assist managers in appropriate mitigation, and can and mitigation, appropriate in managers assist this onecantrackpopulation circumstances. Regional mon populations to flourish under varying ‘threat’ genetics (Baums etal.2005)allowscertain habitat-driven morphology (Hubbard 1988), and environment, surrounding the on based variability important implications formanagers. Population in ‘reactions’ to and recovery from threats, can have A. palmata Management:Monitoring and Discussion Figure 6:Mean percentage of factor.significant 2008 and theBVI in2006-2007 (+ three-spot damselfish ( % Live colonies affected

10 20 30 40 50 60 70 % Live colonies affected 0 10 20 30 40 50 60 0 ) predation inCuracao 2006-2008 and the BVIin 1 SE). populations, such asobserved differences

Sea Aqrm 2008 2007 2006

Sea Aqrm 2008 2007 2006 CURACAO CURACAO

S. planifrons Blau Baii Blau Baii

Boca SM Boca SM A. palmata 1 SE). *Indicates a statistically a 1SE).*Indicates ) territories in Curacao in ) territoriesinCuracao 2006- Site: Site: (df=3) p=0.002* p=0.416Region: (df=1) Year: itoring programsassuch colonies affected) of snail( of colonies affected) responses tothreats, can Site: p=0.775 (df=3) (df=1) p=0.637 Region: Year: Regional differencesin

colonies impacted by coloniesimpacted by p=0.445 (df=2) p=0.265 (df=2) p=0.265 Mtn Pt BVI Mtn Pt BVI

W Dog W Dog

C. potentially help predict the likelihood of population emergency removal by managers (Miller 2001). Snail survivorship, allowing managers to prioritize predation will continue to be monitored at all sites. accordingly (Vardi et al. 2008). Volunteer Involvement in a Monitoring Program: Typical colony morphologies in Curacao and in the Threatened and endangered species receive a great British Virgin Islands were very distinctive; an deal of attention from the media, often creating public average colony in monitored areas of Curacao was interest and volunteers willing to assist with relatively large and frondose, while a typical colony fieldwork. This enthusiasm can potentially in BVI plots was small and mostly encrusting, dramatically expand the spatial scale of regional sometimes with a few short branches. These monitoring studies. However, channeling this interest morphology differences resulted in significant and participation into scientifically meaningful and differences in LAI (Fig. 3), and can have important consistent data can be challenging. For the Acropora implications for asexual fecundity in this species spp. monitoring protocol (Williams et al. 2006), our (Fong and Lirman 1995, Williams et al. 2008). Thus, successful partnership with the SeaMester program in a typical colony in Curacao would be expected to the British Virgin Islands was facilitated by field yield greater asexual recruitment in a moderate storm trainings with experts during monitoring plot set-up or other fragmentation event, which suggests that the and initial surveys. The SeaMester program was an population is relatively better able to sustain itself ideal volunteer partner because of its on-board reproductively. Importantly, LAI generally education staff with a background in marine biology, underestimates actual surface area (particularly for and because it allowed us to gather consistent data more complex colonies) (Williams et al. 2008), so the from remote areas that would otherwise be regional difference in actual live tissue was probably inaccessible. greater. Observations and data collected by SeaMester and Monitored areas in Curacao recovered well other collaborators are always documented following frequent White pox (WPx) observations. In photographically, allowing NOAA staff to quality- 2007, white syndromes (usually WPx, but also assure data by reviewing a subset of observations sometimes WBD) affected 23.9-56.9% of monitored (including all unusual observations). Any questions colonies in Curacao, compared to 19.4-36.0% in from the field crews were addressed as quickly as 2006, and to 0-2.8% for the BVI in 2006. By 2008, possible, and a consensus was obtained prior to final white syndrome prevalence in Curacao fell to 14.6- data entry. 29.3% of colonies affected, evidence that colonies The protocol (Williams et al. 2006) is designed were able to overcome WPx, at least on the short- with various levels of participation options, based on term. Partial mortality from WPx lesions in 2007 was the time and expertise constraints of potential often still visible on the affected colonies during 2008 collaborators. Even if a potential partner is only able surveys, but was usually characterized by an to collect very basic monitoring data, odd or alarming advancing line of live tissue working toward the observations can serve as an ‘early warning system’ center of the old lesion. for further investigation by dedicated field teams. The long-term effects of three-spot damselfish Demographic Acropora spp. monitoring requires territories are not well understood. In this study, field training and advanced scuba diving abilities, territory prevalence was generally low at all particularly for A. palmata surveys (relative to monitored sites, ranging from 0-9.9% of colonies surveys of A. cervicornis, which tends to inhabit affected, except for Curacao site ‘Sea Aqrm,’ which deeper reef areas, and is slightly more compact and hosted significantly more territories, ranging from less structurally delicate). Monitoring sites are usually 19.4-33.7% (Fig. 2, Fig. 6). Subsequent annual very shallow, and located along at the reef crest where surveys will likely shed light on the long-term wave energy and surge is maximized. Volunteers are consequences of these territories on A. palmata required to have a certain degree of buoyancy colony condition. expertise in order to conduct monitoring activities Snail predation was low to moderate at the safely and without damaging corals. monitored sites (Fig. 5), ranging from 2.1-22.2% of Broad scale monitoring projects like this one offer a monitored colonies affected in Curacao, and 0-15.9% unique chance at understanding regional differences of affected in the BVI. In areas with substantial A. in Acropora spp. population response to a variety of palmata population declines, such as the Florida challenges. As global climate change, disease Keys, C. abbreviata grazing activities have been outbreaks, and coastal development continue to affect shown to be particularly detrimental, as snail density the Caribbean region, our broader knowledge of A. and predation increased on surviving colonies (Miller palmata can potentially guide prioritized Caribbean- et al 2002). Observations of detrimental snail wide management based on observed regional predation can potentially serve as justification for population condition and resiliency.

768 Acknowledgements Hubbard DK (1988) Controls of modern and fossil reef Financial support for our monitoring work has come from the development common ground for biological and geological th NOAA Coral Reef Conservation Program and the NMFS Southeast research. Proc. 6 Int. Coral Reef Sym 1: 243-252 Regional Office. Efforts in Curacao initiated from and were Miller MW (2001) Corallivorous snail removal: Evaluation of supported by a grant from Royal Caribbean International impact on Acropora palmata. Coral Reefs 19(3): 293-295 (Adventure of the Seas) and the Education and Research Miller MW, IB Baums, DE Williams, AM Szmant (2002) Status of Department of the Curacao Sea Aquarium. Many thanks for field candidate coral, Acropora palmata, and its snail predator in the support in Curacao from Andrea Anton, Lyza Johnston, Steve upper Florida Keys National Marine Sanctuary: 1998-2001. Piontek and the Education staff of the Curacao Sea Aquarium. NOAA Technical Memorandum. NMFS-SEFSC-479:1-26 Thanks to the SeaMester program coordinators who facilitated this Nagelkerken I, WP Nagalkerken (2004) Loss of coral cover and monitoring effort, and to students that assisted with fieldwork. biodiversity on shallow Acropora and Millepora reefs after 31 years on Curacao, Netherlands Antilles. Bull Mar Sci 74(1): 213-223 References NMFS (2006) Endangered and threatened species: Final listing Baums IB, MW Miller, and ME Hellberg (2005) Regionally determinations for Elkhorn and Staghorn coral. Federal Register isolated populations of an imperiled Caribbean coral, Acropora 71:26852-26861 palmata. Mol Ecol 14:1377-1390 Vardi T, DE Williams, KL Kramer (2008) What is the future of Boulon R, M Chiappone, R Halley, W Jaap, B Keller, B threatened Acropora palmata? Population projections and Kruczynski, M Miller, C Rogers (2005) Atlantic Acropora management recommendations. Proc 11th Int Coral Reef Sym (in Status Review. Report to National Marine Fisheries Service, review) Southeast Regional Office. Williams DE, MW Miller, KL Kramer (2006) Demographic Fong P, Lirman D (1995) Hurricanes cause population expansion of monitoring protocols for threatened Caribbean Acropora spp. the branching coral Acropora palmata (Scleractinia): Wound corals. NOAA Technical Memorandum NMFS-SEFSC-543:91 healing and growth patterns of asexual recruits. Mar Ecol Williams DE, MW Miller, KL Kramer (2008) Recruitment failure 16:317-335 in Florida Keys Acropora palmata, a threatened Caribbean coral. Gladfelter WB (1982) White-Band Disease in Acropora palmata: Coral Reefs 27(3): 697-705 Implications for the structure and growth of shallow reefs. Bull Mar Sci 32:639-643

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