Distribution, Abundance and Adaptations of Three Species of Actiniidae (Cnidaria, Actiniaria) on an Intertidal Beach Rock in Carneiros Beach, Pernambuco, Brazil

Home , Actinia, Actinia bermudensis, Actinia tenebrosa, Actiniidae, Anemonia, Aulactinia

Miscel.lania Zoologica 21.2 (1998) 65

Distribution, abundance and adaptations of three species of Actiniidae (Cnidaria, Actiniaria) on an intertidal beach rock in Carneiros beach, Pernambuco, Brazil

P. B. Gomes, M. J. Belém & E. Schlenz

Gornes, P. B., Belérn, M. J. & Schlenz, E., 1998. Distribution, abundance and adaptations of three species of Actiniidae (Cnidaria, Actiniaria) on an intertidal beach rock in Carneiros beach, Pernarnbuco, Brazil. Misc. Zool., 21.2: 65-72.

Distribution, abundance and adaptations of three species of Actiniidae (Cnidaria, Actiniaria) on an intertidal beach rock in Carneiros beach, Pernambuco, Brazi1.- Bunodosoma cangicum Correa in Belém & Preslercravo, 1973; Actinia bermudensis (McMurrich, 1889) and Anthopleura krebsi Duchassaing & Michelotti, 1860 were studied in an intertidal beach rock at Carneiro's beach, Pernambuco, Brazil. According to the environrnental factors five rnicrohabitats occupied by the species were identified. Randorn surveys were made and a framework was used to calculate the mean specific density of each species in the different habitats. Ten specirnens of each species were rneasured. The Mann-Whitneytest was used to compare size and density of B. cangicum frorn different habitats. Specirnens of B. cangicum were found in three different habitats, with the lowest density (1.1 ind/m2) and the lowest size (1.2x3.8 cm, diam x height) in pools on the flats of the beach rock, exposed to the sun and to the rainfall. In this habitat, there was an increase in the ternperature and salinity of water during dry seasons and the species was almost absent during rainy seasons. In habitats 4 and 5, which were more protected, the mean density was 6.0 and 6.4 and the mean size of 4.5x6.3 cm and 5.3x6.4 cm, respectively. A. krebsi was present in two habitats with high density (24.5 ind/m2)in the habitat with longest air exposure time and this density seerns to be associated with asexual reproduction.A. bermudensiswas present in only one habitat with low density (1.4 ind/rn2)and size of 2.0x2.2 cm. No differences were observed in the statistical cornparison of the density of B. cangicum in two protected zones (P > 0.05) which were thus used as one and cornpared with another unprotected zone. The resulfs showed significant differences (P 10.05). The comparison of size showed differences among the three zones (P 10.05).

Key words: Actiniaria, Ecology, Pernambuco. Brazil

(Rebut: 14 X 97; Acceptació condicional: 27 IV 98; Acc. definitiva: 1 XII 98)

Paula Braga Gomes, Laboratório de Biología de Cnidarios, Depto. Cs. Mar, Fac. Cs. Ex. y Nat., UNMdfj Funes 3250-7600, Mar del Plata, Argentina (Argentine).- Maria Julia da Costa Belém, Retired ProfessorlUFRl, Caixa Postal 24.030, CEP20.522-970, Rio de Janeiro-RI, Brasil (BrazilJ. - Erika Schlenz, Depto. de Zoologia, Inst. de Bioci@ncias,USP Caixa Postal 1 1.461, CEP05422-970, Sáo Paulo-Sfj Brasil (Braziu.

ISSN: 021 1-6529 O 1998 Museu de Zoologia Gomes et al. lntroduction ered during low tide, five zones were identified, according to environmental conditions, Benthic organisms like sea-anemones are sub- forming different microhabitats. These zones mitted to environmental factors that influence did not represent the total area of the beach or determine their distribution, such as the rock but the more conspicuous habitats oc- type of substrate and competitivity for it. The cupied by sea-anemones. fluctuation of tides is also important because The study area was located on the south it influences food availability, gamets and lar- coast of the State of Pernambuco, which has val dispersion and some adaptation is required warm humid weather with temperatures vary- to resist or avoid wave and current action ing from 25°C to 30°C with an average about WAINWRIGH& KOEHL, 1976). Several studies have 26OC; two defined seasons throughout the year. evaluated the actions of these factors. STOTZ one dry (September-February) and one rainy (1979) analysed the zonation of three species (March-August) and a high mean annual rain- of sea-anemones correlating with their mor- fall of about 2,500 mm. The water temperature phological adaptations. HARRIS(1991) consid- varied from 25°C to 32°C reaching 34°C in sum- ered that water flow is a factor of speciation mer in the shallow rock pool in the flats of in some populations of Metridíum senile beach rock. and salinity fluctuated in the ap- Linneus, 1767. These studies were intensified proximate range of 36.4%~- 37%~. on organisms of the intertidal zone, which present higher stress dueto desiccation than those that are submerged (BARNESet al., 1963). Material and methods The intertidal zone is a special place because the intertidal organisms need to develop mor- On the basis of previous work (COMES& MAYAL, phological, physiological and behavioural ad- 1997) and according to observations of envi- aptations to survive in this environment. The ronmental factors, five zones were identified principal adaptations developed by intertidal during low tides representing different sea-anemones are related to: 1. Reproductive microhabitats on the beach rock. The char- biology with different reproductive patterns acteristics of each microhabitat were ana- (SHICKet al, 1979); 2. Different strategies for lysed and correlated with the species presents colonization (SEBENS,1982); 3. lntra and and their size and density. interspecific aggression generally associated to Three species were studied: Bunodosoma the presence of marginal spherulae (BIGGER, cangicum Correa in Belém & Preslercravo, 1980; BRACE,1981); 4. The search for new 1973; Anthopleura krebsi Duchassaing & habitats by displacernent capacity (FUJII, 1985; Michelotti, 1860 and Actinia bermudensis WILLIAMS,1992) and 5. Several mechanisms to (McMurrich, 1889). decrease the wave and desiccation action Randorn surveys were carried out in the (OTTAWAY,1973; ZAMPONI,1981 ). study area on the following dates: 3 Vlll93, The present paper examines how envi- 18 IX 93, 14 X 93 and 12 1 94. The tempera- ronmental conditions influence the distribu- ture and salinity of water were rneasured in tion of three intertidal species of sea-anemo- August 93 (rainy season) and January 94 (dry nes from a beach rock at Carneiros beach season). The following measurements were (State of Pernarnbuco, Brazil) and the adap- made at each time point and in each of the tations developed by each species in differ- five microhabitats: ent microhabitats. 1. The diameter just above the pedal disk and the height of ten specimens of each species was measured. The specimens were Study area randomly selected among sea anemones with common aspect, avoiding specimens con- The area studied was an intertidal beach rock tracted or with distended column. (sensu GUILCHER,1985) at Carneiros beach 2. A framework (50x50 cm) was randomly (8"45' S 35'05' W), State of Pernambuco, Bra- positioned ten times and al1 sea anemones zil. It was 46 m long, 11 m wide and 0.60 m present were counted. high (maximum height). It was submerged al1 For each species in each microhabitat, the year round during high tide. When uncov- specific density (De) was calculated, accord- Miscel.lania Zoologica 21.2 (1998) 67 ing to ODUM(1959). Only the mean specific posed for two or three hours, but sea- density is presented since the seasonal fluc- anemones were permanently submerged in tuations are usually caused by varied repro- the pools, not suffering desiccation. These ductive patterns or different mechanisms of pools had the temperature and salinity of settlement of larvas and juveniles. water affected by exposure to the sun and Finally, a Mann-Whitney test (SOKAL& ROHLF, rainfall, during low tides. 1981) was applied with a significant level of Species present: B. cangicum (De = 1.1 ind/m2). 0.05 to compare the size and density of B. Observations: during rainy seasons the cangicum in different microhabitats at each mean temperature in these pools was 32OC time point. when sea water was 29°C. During dry sea- This was done to determine whether there sons there was an increase in water tempera- were differences between the protected and ture (34OC in pools and 32°C in sea-water) unprotected zone. B. cangicum was the only with a slight increase in salinity in the pools species used because of its distribution in from 36.7%0to 36.9%~.The number of sea- three habitats. A. krebsi was present in two anemones in this habitat decreased during habitats but the density and size of this spe- the rainy season. cies is influenced by its capacity for asexual reproduction. For the comparison of size, Habitat 3 only diameter was used since it is more sta- ble than the height of the sea-anemone. Characteristicr: horizontal crevices on the lateral wall on the shore side. Wave action: no wave action in this habitat. Results Time of air exposure: very prolonged; this was the last sector to be submerged. According to environmental conditions, Species present: A. krebsi (De = 24.5 ind/m2). five different microhabitats occupied by sea Observations: density of this anemone was anemones were identified on the beach high, forming a gregarious population in rock. the crevices with 0.40-0.50 m high.

Habitat 1 Habitat 4

Characteristics: small caverns in the lateral Characteristics: great crevice of 0.60 m deep wall on the sea side. perpendicular to the ocean. The sea-anemo- Wave action: very strong during the rise nes were low on the lateral walls. of the tide, but the caverns provided protec- Wave action: very little; there was a small tion for sea-anemones. channel at low tide and rising tide. Time of air exposure: short, as it was the Time of air exposure: individuals located first sector of the beach rock covered by at the bottom of the crevice were covered by water. the water of the small channel. Other indi- Species present: A. bermudensis and A. vidual~located on the lateral walls of the krebsi; both were randomly distributed with crevice suffered varied degrees of desicca- low specific density (Be = 1.4 ind/m2 and tion according to their height on the wall. De = 3.0 ind/m2, respectively). Species present: B. cangicum (De = 6.0 indlm2). Observations: species showed no prefer- Observations : some anemones on the low ente for different heights on the wall. sector of the lateral wall extended their tentacular crown towards the water channel. Habitat 2 Habitat 5 Characteristics: shallow rock pools formed at low tide in the flats of the beach rock. Characteristics: the low sector of the vertical Wave action: there was no direct wave wall on the shore side near remnant water action. During the rise of tide there was no on the bottom. impact of waves in the area. Wave action: during the rising tide, a Time of air exposure: this habitat was ex- small current was formed due to water en- Comes et al. tering on both sides of the wall. Comparison of the anemone size showed Time of air exposure: moderate; it was the that the three microhabitats are statistically last side reached by the water, but sea-anemo- different (P 10.05). nes, on the bottom, recovered quickly. Species present: B. cangicum (Be = 6.4 ind/m2). Observations: some specimens presented Discussion a distended column with the oral disk in the remnant water on the bottom. The density of al1 species fluctuated throughout the year, but no uniformity was ob- The annual mean size and annual mean spe- served. This fluctuation could be caused by cific density of al1 species in each micro- differences in the reproductive patterns of habitat are shown in table 1. Table 2 shows each species or in their displacement capac- the mean density and size (only diameter) of ity in response to unfavourable environmen- 8.cangicum from protected (microhabitats 4 tal conditions, as discussed by FUJII (1985). and 5) and unprotected (microhabitat 2) The species B. cangicum was almost ab- zones at each time point. The results of the sent in microhabitat 2 during the winter. In Mann-Whitney test showed no differences this habitat the individuals were exposed to in densities between microhabitats 4 and 5 rainfall which directly affected the tempera- (P > 0.05 in al1 time points). These two habi- ture and salinity. tats were thus used as one protected zone Wave action and desiccation caused by and compared with microhabitat 2. At al1 air exposure seem to be the most important time points there were differences between factors characterizing each microhabitat. The the two zones (for al1 U calculated, PI0.05). great diversity of microhabitats probably meets the needs of al1 species, thus keeping them separate. Only microhabitat 1 was shared by two species that were randomly distributed atlow densities. Table 1. Mean size (diameter of column B. cangicum occupied a high number of just above the basal disk x height of different microhabitats. This could be inter- column) and mean specific density (De) preted as indicating this species adapts bet- of sea-anemones in the five habitats. ter than others. One of these adaptations is Tamaño medio (diámetro de la its aggressive capacity due to the large size columna por sobre el disco basal x and the presence of marginal spherulae. For altura de la columna) y densidad media the same species BELÉM& PRESLERCRAVO(1973) específica (De) de las anémonas de mar observed aggressive behaviour in specimens en los cinco hábitats. kept in aquariums. Furthermore, this species needs a mechanism to resist the rise of temperature and salinity during summer in the Species microhabitat 2. In this habitat the virtual absence of B. cangicum in the winter could B. cangicum be interpreted as indicating movements of individuals into less exposed microhabitats in response to the decrease of salinity or mortality of anemones in more exposed areas. Microhabitats 4 and 5 were more protected from wind and sun but the anemones were exposed to air for some time and needed efficient mechanisms to attenuate the effects of desiccation. During low tides some specimens acquired a dome shape, which allowed them to keep water in the coelenteron and decreased their exposed area. This is important due to their large size and coincides with findings by DAYTON(1971). Miscel.lania Zoologica 21.2 (1998) 69

Table 2. Mean density (De, ind/m2 ) and mean size (Ms, cm)(%. Mean; s.d. Standard desviation) of B. cangícum in protected and unprotected zones at each time point. Results of Mann-Whitney test for the comparison of the densities of 8.cangicum from habitats 4 and 5, and (4+5) and 2 (U and its probability). Densidadmedia (De, ind/mzJy talla media (Ms, cm) (Y.Media; s.d. Desviación estándar) de B. cangicum en zona protegida y desprotegida en cada muestreo. Resultados del test de Mann-Whitney para la comparación de las densidades de B. cangicum provenientes de los hábitats 4 y 5 y (4+5) y 2 (valores de U y sus probabilidades).

Protected zone Unprotected zone Habitats (Habitats 4 and 5) (Habitat 2) 4x5 (4+5)x2 Dates De Ms (21s.d.) De Ms (j7ks.d.) U(P) U(P)

Another adaptation to intertidal life is the the low rate of respiration of anemones in presence of vesicles on the column. These protected zones compared with exposed works like a unit of water retention, by cap- zones. In this way individuals conserve more illarity, during the contraction period. The energy which can then be channelled into secretion of mucus to which small particles, greater growth. such as grains of sand, adhere, acts as pro- The behaviour in some individuals of dis- tection from the effects of wind and solar tending their tentacular crown into the rem- radiation. This agrees with observations by nant water has been described previously by STOTZ (1979) for the anemone Phymactis BELÉM& PRESLERCRAVO(1973) and seems to be clematis Dana.1849. AcuÑn & ZAMPONI(1995) related to food catch, the presence of light, and ZAMPONI& PEREZ(1996), studying this same sea tides and avoidance of desiccation dur- species, found a larger sized and greater ing low tides. abundance of individuals in protected zone All these mechanisms presented by B. as compared to exposed areas. This was also cangicum justify its great distribution along observed by BRACE& QUICKE(1986) in Actinia the Brazilian coast and also in Uruguay equina (Linné, 1758). by ZAMPONI& PEREZ(1997) (TRALDI& SCHLENZ, 1990; ZAMPONIet al., in in Aulactinia marplatensis (Zamponi, 1977) press). The low density seems to be caused and Aulactinia reynaudi (Milne-Edwards, by reproductive patterns or settlement ca- 1857) and also in B. cangicum in the present pacity, and a detailed study is needed. Until study. The mean size of this species in pro- the present study asexual reproduction in tected zones (habitats 4 and 5) was bigger this species had not been observed. than that in unprotected ones (habitat 2). A. krebsi was present in two habitats with Nevertheless, there were also differences a high density in microhabitat 3. In this zone between the two protected zones. Since these anemones were seen in the crevice without two habitats showed similar environmental any distance between them. This very close patterns, this could be associated with stages distribution and the smaller size of speci- of development of species. mens, as compared to these from others Some authors (BRACE& QUICKE,1986; MULLER- beaches in Pernarnbuco State (first author's PARKER,1987) associated the larger size with personal observations) seem to be related to Gomes et al. its great capacity for asexual reproduction zone to develop mechanisms which allow by longitudinal fission described by BEL~M& them to occupy microhabitats on the basis PINTO(1990) and observed in some individu- of their ecological preference and the envi- als in the study area. It seems that in this ronmental conditions. region A. krebsi used a reproductive strat- egy based on asexual reproduction, probably due to the stress conditions to which it Resumen is submitted. EXCOFFON& ZAMPONI(1995) observed the same pattern in the anemone Distribución, abundancia y adaptaciones de Tricnidactis errans Pires, 1988 in Mar del Plata, algunos Actiniidae (Cnidaria, Actiniaria) en Argentine. A detailed study of the repro- un arrecife intermareal de la playa de los duction strategies of this species is needed Carneiros, Pernambuco, Brasil to clarify this question. The presence of marginal spherulae in A. En este trabajo fue analizada la distribución y krebsi indicates an aggressive capacity, prob- abundancia de Bunodosoma cangicum Correa ably lower than that presented by B. cangicum in Belém & Preslercravo, 1973; Anthopleura due to the difference in size between them. krebsi Duchassaing & Michelotti, 1860 y This capacity could contribute to the nu- Actinia bermudensis (McMurrich, 1889) en un merical superiority of this species compared arrecife de arenito intermareal de la playa de with others and also to its isolation, with los Carneiros, Pernambuco, Brasil. Según las apparently clonal behaviour. condiciones ambientales fueron identificados Other studies on species from the genus cinco microhábitats distintos donde se Anthopleura (FRANCIS,1973; SMITH & Pons, ubicaban las especies, con distintos tiempos 1987) demonstrated that clonal behaviour is de exposición al aire y acción de las olas. very common in this genus. A lo largo de un año se realizaron censos In both microhabitats occupied by A. con la utilización de un cuadrado de 50x50 cm krebsi, this species is in protected zones such para el cálculo de la densidad específica me- as small caverns (microhabitat 1) or in crevices dia de cada especie en los diferentes (microhabitat 3). The small size and the con- microhábitats. In situ se midió la talla (diáme- traction capacity allow this species to occupy tro y altura) de diez ejemplares de cada espe- very protected zones and also decrease the cie en cada hábitat (tabla 1). amount of body surface exposed to desicca- La especie B. cangicum estuvo presente tion. In spite of this, individuals, specially in en tres hábitats distintos con menor densi- microhabitat 3, were exposed to a very long dad (1,l ind/m2) y menor talla (2,2x3,8 cm, period to air and needed some adaptations. diam x alt) en el hábitat 2, formado por In the column there are numerous verrucaes pozas en la plataforma superior del arrecife to which particles, such as pieces of shells y el más expuesto a la acción del sol y de la and calcareous algae adhere, thereby form- lluvia. En estas pozas hubo un incremento ing a protective layer which protects against de la temperatura y salinidad del agua du- desiccation. rante el verano y una casi ausencia de la A. bermudensis was only observed in especie en el período lluvioso. En los hábitats microhabitat 1 and few individuals were 4 y 5, más protegidos, tuvo densidad media found, suggesting this species is not well de 6.0 y 6.4 ind/m2y tallas medias de 4,5x6,3 adapted to this environment. In fact, this cm y 5.3x6.4 cm, respectivamente. dark red anemone clearly absorbs solar heat A. krebsi se presentó en dos hábitats dife- and its smooth column favours desiccation. rentes con talla pequeña y densidad baja en The only adaptations presented by this spe- cavernas ubicadas en la pared del arrecife cies are the domeshape during low tide que miraba al mar (0,9xl,l cm y 3,O ind/m2)y and its location in a microhabitat quickly gran densidad en el ambiente con mayor covered by water, thus resisting the wave tiempo de exposición al aire, donde esta impact and being in protected zones such densidad parece estar relacionada con la ca- as small caverns. pacidad de reproducción asexuada presen- The results of the present study confirm tada por dicha especie. the need for sea anemones in the intertidal A bermudensis estuvo presente en un solo hábitat com pequeña densidad (1,4 ind/m2)y pecific acrorhagial aggressive behaviour

" talla media de 2,0x2,2 cm. among sea anemones: a recognition of El test de Mann-Whitney fue utilizado self and not-self. Biol. Bull., 159: 117-1 34. para comparar las tallas y densidades de la BRACE,R .C., 1981. lntraspecific aggression in especies B. cangicum en los distintos hábitats the colour morphs of the anemone (tabla 2). La densidad de esta especie en las Phymactis clematis from Chile. Mar. Biol., dos zonas protegidas no mostró ninguna 64: 85-93. diferencia significativa (P > 0.05). Estas dos BRACE,R. C. & QUICKE,D. L. J., 1986. Seasonal zonas fueron comparadas con otra zona changes in dispersion within an aggre- desprotegida y se observaron diferencias sig- gation of the anemone Actinia equina nificativas (P 10,05). with a reappraisal of the role of Con relación a la talla, las tres zonas pre- intraspecific aggression. J. Mar. Biol. Ass. sentaron diferencias entre sí (P 1 0,05). Se U. K., 66: 49-70. observó que la distribución y densidad de DAYTON,P. K., 1971. Competition, disturbance, las especies están relacionadas principalmen- and community organization: the provi- te con la incidencia de las olas y el tiempo sion and subsequent utilization of space de exposición al aire. Se discuten las adapta- in a rocky intertidal community. Ecol. ciones morfológicas, fisiológicas y compor- Monogr., 41 : 351-389. tamentales de las especies según su distribu- EXCOFFON,A. C. & ZAMPONI,M. O., 1995. The ción en los distintos hábitats. reproductive biology of Tricnidactis errans (Actiniaria, Haliplanellidae) from rocky shore of Mar del Plata (Argentina). Cah. Acknowledgements Biol. Mar., 36: 175-179. I FRANCIS, L., 1973. Clone specific segregation in We want to thank to Dr. Mauricio O. the sea anemoneAnthopleura elegantissíma. Zamponi for his suggestions and revision of Bi01. BuII., 144: 64-72. the paper and Prof. Mariel Amato for the FUJII, H., 1985. Locomotion and distribution revision of the English version. of sea anemone Anthopleura asiatica (Uchida) in microhabitat. Special Publica- tion of the Mukaishima Marine Biological References Station, 252: 167-172. I GOMES,P. B. & MAYAL,E. M., 1997. Levanta- Acuiún, F. H. & ZAMPONI,M. O., 1995. Ecología mento preliminar das anemonas-do-mar de anémonas intermareales. Densidad, dis- (Cnidaria, Actiniaria) da costa de Pernam- persión y autoecología de Phymactis buco, Brasil. Biociencias, 5(2): 45-52. clematis Dana, 1849 (Anthozoa: Acti- GUILCHER,A., 1985. Coral reef geomorphology niaria). Ciencias Marinas, 21(1): 1-12. 1-XIII. John Wiley & Sons, New York. BARNES,H., FINLAYSON, D. M. & PIATIGORSKY,J., HARRIS,L. C., 1991. Comparative ecology of 1963. The effect of desiccation and anaero- subtidal actiniarians from the coasts of bic conditions on the behaviour, survival California and the Gulf of Maine, USA. and general metabolism of three common Hydrobiologia, 21 6/217: 271-278. cirripedes. J. Anim. Ecol., 32: 233-252. MULLER-PARKER,G., 1987. Seasonal variation in BEL~M,M. J. &PINTO,S. M., 1990. Morphological light-shade adaptation of natural popula- and microanatomical study of Anthopleura tions of the symbiotic sea anemone krebsi Duchassaing & Michelotti, 1860 Aiptasia pulchella (Carlgren,1943) in Ha- (Cnidaria, Anthozoa, Actiniidae), a new record waii. J. Exp. Mar. Biol. Ecol., 112: 165-183. in Brazil. An. Acad. Bras. Ci., 62(2): 183-192. ODUM,E. P., 1959. Fundamentals of Ecology. W. BELÉM, M. J. & PRESLERCRAVO,J. C., 1973. B. Saunders Co., Philadelphia & London. Contribui~oesao conhecimento da fauna OITAWAY,J. R., 1973. Some effects of tempera- de Cnidarios do Espírito Santo, Brasil. l. ture, desiccation and light on the inter- Consideracbes sobre Actiniaria do Muni- tidal anemone Actinia tenebrosa Farquhar cípio de Aracruz, ES. Bol. Mus. Biol. Prof. (Cnidaria: Anthozoa). Aust. J. Mar. Fresh. Mello LeitSo, S. Zoologia, 80: 1-14. Res., 24: 103-126. BIGGER,C. H., 1980. lnterspecific and intras- SEBENS, K. P., 1982. Recruitment and habitat 72 Comes et al.

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