ABSTRAKBulu babi adalah kelompok hewan tidak bertulang belakang Avertebrata yang termasuk dalam filum Echinodermata.  Hewan ini banyak ditemukan  pada perairan  dangkal dan biasanya terdapat  pada padang lamun dan daerah  terumbu karang.  Di seluruh dunia, terdapat kurang lebih 800 jenis bulu babi dari kelas Echinodea   yang   terbagi dalam dua subkelas yaitu Perischoechinoidea dan Echinoidea. Oi Indonesia sendiri, terdapat  kurang  lebih  84 jenis  bulu babi  yang berasal  dari  31 suku dan 48  marga. Perairan pulau  Gill  Raja  Panjang memiliki beberapa  biota echinodermata salah satunya bulu babi. Bulu babi tersebar di ekosistem padang lamun dan terumbu karang. Keberadaan bulu babi berpengaruh pada  terumbu  karang,  karena dapat  mejadi  kontrol  bagi perkembangan mikroalga  dan  meningkatnya bulu babi akan  berdampak   negatif bagi ekosistem lamun. Bulu babi yang di dapatkan yaitu Diedema setosum, Sa/macis belli, Mespi/ia g/obu/us, Echinometra mathaei. Kelimpahan bulu babi di Pulau Gill Raja berkisar antara 3-4.33 ind/m2,  dengan kelimpahan tertinggi terdapat di Stasiun II 4.33 ind/m2 dan terendah di stasiun I yaitu sebesar 3 ind/m2. Keanekaragaman bulu babi di Pulau Gili Raja tergolong dalam keanekaragaman rendah  dengan nilai sebesar 0,415, keseragaman tergolong keseragaman rendah sampai tinggi mempunyai nilai sebesar 0,743 sempai 0,498, dan dominansi tergolong  dalam dominansi sedang dengan  nitai sebesar 0,712.Kata Kunci  : Bulu Babi,  line transect,  dan Statified random  sampling.ABSTRACTSea urchins are a group of invertebrate animals belonging to the phylum Echinoderms. These animals are mostly found in shallow waters and are usually found in seagrass beds and coral reef areas. Worldwide, there are approximately 800 species of sea urchins from the Echinodea class which is divided into two subclasses, Perischoechinoidea and Echinoidea. Oi Indonesia itself, there are approximately 84 types of sea urchins originating from 31 tribes and 48 genera. The waters of the Gill Raja Panjang island have several echinoderms, one of which is sea urchins. Sea urchins are scattered in seagrass and coral reef ecosystems. The presence of sea urchins has an effect on coral reefs, because it can be a control for microalgae development and the increase in sea urchins will have a negative impact on seagrass ecosystems. The sea urchins that were obtained were Diedema setosum, Sa/macis belli, Mespi/ia g/obu/us, Echinometra mathaei. The abundance of sea urchins on Gill Raja Island ranged from 3-4.33 ind/m2, with the highest abundance at Station II 4.33 ind/m2 and the lowest at station I at 3 ind/m2. The diversity of sea urchins on Gili Raja Island is classified as low diversity with a value of 0.415, uniformity belonging to low to high uniformity has a value of 0.743 to 0.498, and dominance is classified as moderate dominance with a value of 0.712.Keywords : Sea urchins, line transect,  dan Statified random  sampling 
                        
                        
                        
                        
                            
                                Copyrights © 2022