1 The excavating sponge Cliona orientalis as a coral

G 2 reef competitor’s on Krakatau Islands colonisation, u 3 Indonesia i 4 d 5 6 Singgih Afifa Putra1 a 7 n 8 1 Department of Marine Education, LPPPTK KPTK – Ministry of Education and Culture, Gowa, c 9 South Sulawesi, Indonesia e 10 – 11 Corresponding Author: r 12 Singgih Putra 13 Jl. Diklat No 30 Pattallassang, Gowa, South Sulawesi, 92171, Indonesia e 14 Email address: [email protected] m 15 o 16 The recovery of coral reefs on Krakatau Islands after the destructive eruption in 1883 has been v 17 reported in very limited study (Putra et al. 2014). Coral reefs began to grow on all islands in the 18 Krakatau volcanic complex, including the highly active volcano island i.e. Anak Krakatau (north e 19 to west coast). Survival of coral reefs in the Krakatau Islands influenced by several factors such as t 20 predation, diseases, soft coral overgrowth, and also sediment covers (Putra et al. 2014). Somehow, h 21 sponges as one of killer-competitor of coral reefs have never been reported in the Krakatau Islands. 22 In 2012 and 2013, the author conducted research in three islands of Krakatau Volcanic Complex i 23 (i.e. Rakata, Panjang, Anak Krakatau). The survey was done with line intercept transect and found s 24 about 0 to 5 % of sponges cover from six localities. Generally, Cliona orientalis Thiele, 1900 b 25 (encrusting form) were found as an aggressive and competitive species to reef-building corals (Fig. 26 1a). Some sponges were found attacked and killed massive Porites sp. (Fig. 1c-d). This excavating o 27 sponge is known as bioeroding demosponge with very competitive and successful colonizer in a x 28 certain environment (Schönberg 2000; Schönberg and Wilkinson 2001; Schönberg 2003). Despite b 29 their competitiveness, the sponge also found inhabited by other organisms like Lance blenny, 30 Aspidontus dussumieri Valenciennes, 1836 (Fig. 1b). Before, C. orientalis was documented e 31 frequently found in eastern Indonesia (van-Soest 1990). This report presents a wider distribution f 32 of C. orientalis in the western part of Indonesian Archipelago. o 33 r e s u b m i t t i PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.27594v1 | CC BY 4.0 Open Access | rec: 18 Mar 2019, publ: 18 Mar 2019 n 34 35 Figure 1: Excavating sponge as a competitor of coral reefs in Krakatau Islands. (A) Some colonies 36 of excavating sponges (circles) commonly found in Rakata Island (06.13561°S, 105.45014°E). (B) 37 Close up of excavating sponge Cliona orientalis inhabited by Lance blenny Aspidontus dussumieri 38 dwelling old serpulid tube (scale bar 1 cm). (C) Excavating sponge covered almost 90 % of Porites 39 sp. (D) Three colonies of Porites sp. were covered by C. orientalis, one colony full covered 40 (middle), > 90 percent covered (left), > 75 percent covered (right), with some fish bites (arrow).

PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.27594v1 | CC BY 4.0 Open Access | rec: 18 Mar 2019, publ: 18 Mar 2019 41 42 Acknowledgements 43 Author thank to several rangers of Lampung Nature Conservation Agency (BKSDA Lampung) – 44 Ministry of Forestry for assisted during the survey. Research permit were issue by BKSDA 45 Lampung under SIMAKSI No: SI.800/BKSDA.L-1.Prl/ 2012. 46

47 References 48 Putra SA, Damar A, Samosir AM (2014) Colonization of coral communities in the 49 Krakatau Islands Strict Marine Nature Reserve, Indonesia. Indonesian Journal of Marine 50 Science 19(2): 63-74 51 Schönberg CHL (2000) Bioeroding sponges common to the central Australian Great Barrier Reef: 52 Descriptions of three new species, two new records, and additions to two previously 53 described species. Senckenbergiana Maritima 30(3-6): 161–221 54 Schönberg CHL (2003) Substrate Effects on the Bioeroding Demosponge Cliona orientalis. 2. 55 Substrate Colonisation and Tissue Growth. Marine Ecology 24(1): 59–74 56 Schönberg CHL and Wilkinson CR (2001) Induced colonization of Great Barrier Reef corals by a 57 clionid bioeroding sponge. Coral Reefs 20: 69–76 58 van-Soest RWM (1990) Shallow water reef sponges of Eastern Indonesia. In Rutzler K (ed) New 59 Perspectives in Sponge Biology. Smithsonian Institution Press, London, pp 302–308

PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.27594v1 | CC BY 4.0 Open Access | rec: 18 Mar 2019, publ: 18 Mar 2019