Interspecific Aggression in Hermatypic Corals from Panjang Island

Abstract

Penelitian terhadap agresi interspesifik antara koral hermatipik dari Pulau Panjang dilakukan di akuarium antara bulan September - Desember 2000 di Laboratorium Kelautan Teluk Aawur Iepara. Resultan hirarki dibuat dengan melakukan rangking terhadap kemampuan suatu spesies untuk 'merusak' kompetitor. Studi lapangan dilakukan untuk mekonfirmasi apakah spesies paling agresif merupakan spesies yang mendominasi. Hasil munjukkan ditemukannya proses fusi terhadap semua pasangan dari koloni yang sama. Histoinkompatibilltas ditemukan setelah seminggu waktu kontak dengan adanya respon penolakan. Hal ini menunjukkan bahwa digesti oleh filamen mesenterlal merupakan mekanisme paling penting dalam proses agresi, diikuti dengan overgrowth dan unindirectional woundings yang diakhiri dengan reaksi penolakan. Stylophora pistillete merupakan spesies paling agresif, diikuti oleh Pectinia sp. Dan Pocillopora damicornis. Sedangkan Montipora dan Acropora memiliki sifat agresif lemah. Hasil ini menunjukkan bahwa karakteristik morfologi berperan penting dalam intereksi kompetitif. Tidak ditemukan interaksi intransitif pada hirarki yang ada. Namun studi lapangan menunjukkan bahwa spesies paling agresif tidak selalu merupakan spesies yang mendominasi. Agresifitas diduga bukan merupakan satu-satunya factor yang menentukan distribusi dan zonasi karang di Pulau Panjang. Kata kunci: Agreasi, interspesiflk, karang, Pulau Panjang Interspecific aggression between hermatypic corals on Panjang Island reef has been investigated by aquarium study. This study was performed between September and December 2000 at Marine Station Research Center, Kampus Teluk Awur Jepara. Resultant hierarchy was constructed by ranking the abilities of species to damage competitors. Field study was conducted to check whether the most highly aggressive species are those occupying the greatest area of sea floor. Fusion was observed In all same colony pairs by the end of experiment, regardless duration after initial contact. Hlstoincompatibility was visible after a week of contact with rejection was the most common response. It suggest that digestion by mesenterial filaments is the most important mechanism of aggression followed by overgrowth and unidirectional woundings that ended as a stand-offs reaction. Stylophora pistillata being the most highly aggressive species in Panjang Island followed by Pectinia sp and Pocillopora demtcornts while Montipora and Acropora are weakly aggressive. This result confirmed that differences in morphological characteristics play an important role during competitive interactions. No intransitive interaction was observed from the present hierarchy. Field study revealed that the most highly aggressive species is not necessary to those occupying the greatest area of sea floor. Aggression may not the single factor which influence spatial distribution and zonation of coral reefs in Panjang Island. Keywords: interspecific anggression, corals, Panjang Island