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Rev. BioI. Trop., 46 Sup!. 5: 145-156, 1998 Epizoism: a new threat to coral health in Caribbean reefs Amfried Antonius 1 and Enric Ballesteros2 1 Ins1. Paleontology, Univ. Vienna, Althanstrasse 14, A-1090 Vienna, AuStria. 2 CentreEstudis Avanyats-CSIC, C. Santa Bm-bara sin, E-17300 Blanes, Spain. (Rec. 25-VIl-I997. Rev. 26-1II-1998. Acep. 5-V-1998) Abstract: Coral reefs around Carrie Bow Cay, Belize, Central America were investigated in 1972 and reefs of the John Pennekamp Coral ReefState Park offKey Largo, Florida in 1973. Both sites were resurveyed in 1997 and anew threat to coral health was found: a rather epizootic occurrence of other organisms overgrowing living coral. On the reef-flat of the Barrier Reef north of Carrie Bow Cay, there are fields of Acropora cervicornis and Poriles poriles, scattered over shallow sand-bottom. A large number of these corals show either "tufts" of blue-green algae, or fila­ mentous "flags". Both may cover substantial portions ofindividualcoralla; the living tissue disappeared at the ofcon­ tact area. Another type ofovergrowth on living corals is represented by the red alga Melapeyssonnelia cora/lepida, as well as the brown alga Lobophora variegala. Both overgrow mainly Mi/lepora complanala and M. alcicornis, but also other corals with smooth surface, such as Poriles poriles and P aSlreoides. This syndrome occurs about equally abundant around Carrie Bow Cay, Belize, and in reefs offKey Largo, Florida. A similar kind oftightly attached over­ growth is represented by the sponge Cliona caribbea. It was found regularly in the reefs around Carrie Bow Cay on a wide variety of coral species. An identical type ofepizoism is represented by Chondri/la cf nucula, which, so far, was observed only in Belize. All these new syndromes together amount to a considerable coral-degrading factor, which was not found in these reefs 25 years ago. Key words: Reefcorals, space competitors, epizoism, coral death, reef degradation. Coral reefs around Carrie Bow Cay, Belize, When both reef-sites were resurveyed III Central America, located at 16° 48' N, 88° 05' early 1997, the most striking differences in W (Fig. 1) were investigated in 1972, and reefs comparison to the old surveys were that : 1) of the John Pennekamp Coral Reef State Park much larger portions of reef-crest and back­ off Key Largo, Florida, located at 25° 07' N, reef areas are dead today, and 2) a qualitatively 80° 18' W (Fig.2) in 1973 (Antonius 1974). new threat to coral health has emerged, consist­ Sinc~ 1972 was the year of discovery of the ing of a rather epizootic occurrence of certain black-band disease (BBD) of reef corals Cyanophyta, Rhodophyta, Phaeophyta, and (Antoni~ 1973), special emphasis in both sur­ Porifera overgrowing living corals. Thus, sub­ veys was put on coral health. Thus, along cer­ ject ofthis paper is a qualitative description of tain transects, live, diseased, otherwise impact­ newly observed phenomena of epizoism ed, and dead corals were recorded. Impacts on degrading coral health. live, corals other than diseases was found to be This does not mean that the "old" maladies mainly feeding damage by the fireworm have disappeared. On the contrary, BBD and Hermodice carunculata (Antonius 1973, 1975) white-band disease (WBD) are still common at in these old surveys. both locations (Antonius 1981), coral-tissue- 146 REVISTA DE BIOLOGIA TROPICAL ! t N ....,,-,) Victoria 16°50' ('" l.-.~_........ o I ~ . Sillee Point ../ (_...•..•...... ~ Carrie Bow Cay l ........! ! I 1; ,I / Channel { 5km \ 88°10' Fig. I. To the left (= west) the mainland of Belize just south ofthe town of Dangriga with the mouth ofthe Sittee River. To the right (= east) the patch-reefsystem ofthe lagoon and the barrier reefwith Tobacco Reef in the north, Curlew Bank in the south and Carrie Bow Cay in the center. Hawk p~ ROCkS:'?'· J 25°07' Greci~·~ Rocks if :-'{:" 1 km 80°18' Fig. 2. To the left (= west) Key Largo with Largo Sound (L. S.) and South Sound Creek (S). To the right (= east) the White Banks area with the Key Largo Dry Rocks and Grecian Rocks reefs. The shelfedge marks the 301n isobath. bleaching (TBL) is rampant especially in MATERIALS AND METHODS Belize (Antonius, in prep.), while Florida is being invaded by an array ofpreviously little or Underwater, on-site observations were unknown syndromes, such as white-pox, yel­ made along a total oftwelve transects: 3 north low-blotch, white-plague (Goreau et al. 1998), and 3 south ofCarrie Bow Cay, Belize, as well white-plague type 11 (Richardson et al. 1998), as 3 transects on Key Largo Dry Rocks and 3 or rapid-wasting disease (Cervino et al. 1997). on Grecian Rocks, Florida. However, in our opinion, the combined phe­ The Belt Method was used throughout in nomena of epizoism, described in this paper, order to register all syndromc:s on corals in the may pose an even more severe threat to coral transects as indicators ofthe health condition of health and wellbeing of the entire reef ecosys­ the respective reefs (Antonius 1995a). It is a tem. semi-quantitative time-count technique that uses 30-min scans to quantify frequency of occurrence of coral diseases and other coral- ANTONIUS & BALLESTEROS: A new threat to coral health 147 degrading syndromes on a scale from zero to ing data on the changes that have taken place in six. However, for the purpose ofthis paper, per­ these reefs over time, will be forthcoming at a centages of afflicted specimens of the respec­ future date (Antonius, in prep.). tive coral species were calculated. An overall The second point listed in the Introduction, account ofcoral (and thus reef) health, dealing the new phenomena of other organisms over­ with all the presently known syndromes on reef growing living coral, is the subject of this corals (Antonius 1995b), will be published paper. We would like to point out that the des­ elsewhere (Antonius, in prep.). ignation as "new" phenomena shall not suggest Samples taken in the field were preserved in that these syndromes had not existed in the 4% formalin-seawater, as well as in 70% dena­ past, but merely that they had not been a threat tured ethanol. All voucher specimens were to coral and to coral reef health a few decades deposited in the Herbario del Centre d'Estudis ago. Avancats, CSIC, in Blanes, Spain. The respec­ tive accession-numbers are listed in the Blue-green algae: The Atlantic Barrier "Results" section. Reef immediately north of Carrie Bow Cay, Belize, consists ofan approximately 50m-wide reefcrest, made up mainly ofAcropora palma­ RESULTS ta and Millepora complanata, followed by a For somebody who has not been back to these reefs for 25 years, the first sight was a TABLE 1 real shock. Especially the reefs around Carrie Summary ofpercentages ofcoral populations Bow Cay, in Belize which were teeming with overgrown by either cyanophytes, or macroal­ grouper, snapper, triggerfish, other colorful reef gae, or sponges in reefs ofCarrie Bow Cay, Belize and Key Largo, Florida. (n.r. = not reg­ fish, and with lobster and conch in the old days, istered) are now ghostly empty. The only larger fish seen during one month of survey was one par­ rotfish and two barracudas. Fish populations Belize Cyanophytes Florida % growing on % inside the National Marine Sanctuary at Key Largo, Florida, appeared to be in better shape. 50 Acropora cervicornis n.r. However, as mentioned under point one in the 50 Poriteslorites nx. n.r. reporte on 80 Introduction, large portions of reef-crest and Scleractinia and back-reef, which were documented as alive and Gorgonia in good condition 25 years ago, were found dead today. And this is true for Carrie Bow Belize Macr~algae Florida % growmgon % Reef in Belize, as well as for Grecian Rocks and Key Largo Dry Rocks in Florida. In all of 5 Millepora complanata IQ Millepora alcicornis 10 these reefs, large expanses ofstill standing, rel­ 5 5 Porites astreoides 2 atively undamaged coral skeletons (mainly 10 Porites porites 2 Acropora palmata and Millepora complanata) can be found, as well as other areas where these Belize Sponges Florida % growing on % skeletons are weathered down to stumps, and others again where even these are obliterated IQ Dendrogyra cylindrus n.r. and reduced to rubble. Carrie Bow Reef was 5 Acropora palmata 1 5 Millepora complanata 1 surveyed in 1972 (Antonius unpublished), and 2 Montastrea annularis n.r. the Key Largo reefs in 1973 (Antonius 1974). 2 Diploria strigosa n.r. An accounting ofthese old (1972/73) results in 2 Diploria labyrinthiformis n.r. comparison with the new (1997) ones, contain- 1 Agaricia tenuifolia n.r. 148 REVISTA DE BIOLOGIA TROPICAL Fig. 3. The typical "tufts" ofOscillatoria submembranacea on branches ofPorites porites. One ofthe branches has been com­ pletely covered by the cyanophyte. roughly 200m-wide reef flat that is about lm swept in from the outer reef, getting caught in deep behind the reef crest and 2m deep toward the branches, is not known at present. the lagoon (RUtzler and Macintyre 1982). Right Following Drouet's taxonomy, we identi­ behind the reefcrest, the bottom is mostly rub­ fied the "tufts" as Oscillatoria submem­ ble inbetween numerous Montastrea annularis branacea and the "flags" as Schizothrix mexi­ and Porites astreoides heads. Towards the cana, while according to classic taxonomy the lagoon, the floor becomes a sand-flat, studded "tufts" also match the characteristics of with Acropora cervicornis and Porites porites Microcoleus lyngbyaceus, and the "flags" those colonies. of Oscillatoria margaritifera. Since the taxon­ As mentioned earlier, compared to 1972, omy ofblue-greens is notoriously difficult, def­ the 1997 survey showed a much larger percent­ inite identification will undoubtedly require age of still standing, but dead coral colonies.

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