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Jenis Kerang (Bivalvia) Daerah Pasang Surut Di Perairan Desa Teluk Bakau

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Jenis Kerang (Bivalvia) Daerah Pasang Surut Di Perairan Desa Teluk Bakau E-ISSN: 2685-8827 Jurnal Manajemen Riset dan Teknologi Universitas Karimun (JURNAL MARITIM) Vol. 2 No. 1. Agustus 2020 IDENTIFIKASI KEANEKARAGAMAN JENIS - JENIS KERANG (BIVALVIA) DAERAH PASANG SURUT DI PERAIRAN DESA TELUK BAKAU Mey Krisselni Sitompul Dosen Fakultas Sains dan Teknologi Universitas Karimun No Tel: 082288892040. Surel: [email protected] Abstrak Penelitian ini bertujuan untuk mengidentifikasi keanekaragaman jenis kerang (Bivalvia) di daerah pasang surut yang terdapat di perairan Teluk Bakau, Kabupaten Bintan, Provinsi Kepulauan Riau. Metode yang digunakan adalah metode Purposive sampling. Pengambilan sampel dilakukan pada saat surut terendah. Sampel diambil dari 3 stasiun, dimana pada masing-masing transek terdapat tiga titik sampling (3 plot) dengan ukuran 1 x 1 m2. Jarak antar garis transek adalah 50 meter. Hasil penelitian dari 4 stasiun ditemukan sebanyak 1.772 kerang Bivalvia dengan 14 jenis spesies yang berbeda. Suhu di masing-masing stasiun berkisar antara 29.90c – 30.50c. Lokasi pH pada 4 stasiun penelitian berkisar antara 8.33 – 8.38 sedangkan untuk DO dari 4 stasiun berkisar antara 7.2 mg/L – 7.7 mg/L. Hasil perhitungan keanekaragaman H’, peneliti menemukan keanekaragaman Perairan Desa Teluk Bakau bernilai H’= 2.451, dengan nilai tersebut tingkat spesies kerang (Bivalvia) yang ditemukan adalah sedang, (H’>3,322) yang berarti di perairan Desa Teluk Bakau tersebut keanekaragaman sedang, produktivitas cukup, kondisi ekosistem cukup seimbang dan tekanan ekologis sedang. Kata Kunci: Bivalvia, Metode, Teluk Bakau, pH, DO, Suhu, Keanekaragaman H’. I. PENDAHULUAN Zona Intertidal (Pasang surut) merupakan daerah tersempit dari semua daerah yang terdapat di samudera dunia. Walaupun luas daerah ini sangat terbatas, tetapi memiliki variasi fakrot lingkungan yang terbatas dibandingkan dengan daerah lautan lainnya. Pada daerah ini terdapat beragam kehidupan yang lebih besar salah satunya yaitu kerang-kerangan termasuk kelas bivalvia. Wilayah pesisir merupakan daerah pertemuan antara darat dan laut yang masih di pengaruhi sifat-sifat laut seperti pasang surut dan proses alami yang terjadi di darat seperti aliran air tawar maupun yang di sebabkan oleh kegiatan manusia di darat. Desa Teluk Bakau merupakan salah satu desa yang terletak di Kabupaten Bintan. Berdasarkan hasil survei pendahuluan yang dilakukan, zona intertidal perairan Desa Teluk Bakau banyak ditemukan berbagai aktivitas, seperti: pariwisata, aktifitas nelayan, dan rekreasi masyarakat local yang mencari kerang untuk di konsumsi sendiri. Bivalvia adalah biota yang biasa hidup di dalam substrat dasar perairan (biota bentik) yang relatif lama sehingga biasa digunakan sebagai bioindikator untuk menduga kualitas perairan. 42 E-ISSN: 2685-8827 Jurnal Manajemen Riset dan Teknologi Universitas Karimun (JURNAL MARITIM) Vol. 2 No. 1. Agustus 2020 Kepadatan jenis adalah sifat suatu komunitas yang menggambarkan tingkat keanekaragaman jenis organisme yang terdapat dalam komunitas tersebut. Kepadatan jenis bergantung pada pemerataan individu dalam tiap jenisnya. Kepadatan jenis dalam suatu komunitas dinilai rendah jika pemerataannya tidak merata. (Jamila, Nasution, & Efriyeldi, 2018). II. METODE PENELITIAN Penelitian ini dilaksanakan di zona intertidal pada bulan Juli hingga Agustus 2019 di perairan Desa Teluk Bakau, Kecamatan Gunung Kijang, Kabupaten Bintan. Penelitian ini menggunakan metode observasi yaitu metode penglihatan secara langsung. Metode observasi dalam penelitian ini, digunakan untuk melihat daerah habitat kerang, kedalaman kerang serta melakukan dokumentasi dan dilanjutkan dengan studi pustaka untuk melihat keanekaragaman kerang bivalvia. Jarak antar stasiun lebih kurang 500 meter, masing-masing stasiun terdiri atas tiga transek, transek garis ditarik tegak lurus dengan garis pantai berdasarkan zona intertidal yaitu di zona pasang tertinggi (upper zone), zona batas pasang tertinggi dan surut terendah (middle zone) dan zona batas surut terendah (lower zone). Pada Masing-masing transek terdapat tiga titik sampling atau total plot, dalam satu stasiun terdapat 9 plot dengan ukuran 1x1m2. Jarak antar garis transek adalah 50 meter. Berikut bagan stasiun penelitian. Penarikan pada setiap sub Stasiun pengamatan sebagai berikut: Gambar 1. Desain Penarikan Pada Setiap Sub Stasiun Pengamatan Indek Keanekaragaman (H’) Keanekaragaman bivalvia dihitung dengan menggunakan indeks keanekaragaman dari (Shannon Wiener, 1963) dalam (Fachrul, 2012) seringkali peneliti menggunakan formula Shannon-Wienner (H’) menggunakan Log 10. Dengan formula berikut: 43 E-ISSN: 2685-8827 Jurnal Manajemen Riset dan Teknologi Universitas Karimun (JURNAL MARITIM) Vol. 2 No. 1. Agustus 2020 Keterangan: Dimana: Pi=∑ni/N H : Indeks keragaman Shannon-Wienner Pi : Jumlah individu suatu spesies/ jumlah total seluruh spesies ni : Jumlah individu spesies ke-i N : Jumlah total individu Angka indeks keanekaragaman tersebut selanjutnya dinilai sebagai berikut: H’ yaitu: H’<1,0 = Keanekaragaman rendah; 1,0<H’<3,322 = Keanekaragaman sedang; H’>3,322 = Keanekaragaman tinggi III. HASIL DAN PEMBAHASAN 3.1 Stasiun Penelitian Pada Stasiun Penelitian kedalaman galian untuk mendapatkan spesies kerang Bivalvia berkisar antara ± 1 – 60 cm, jenis Tridacna Crocea ditemukan di dalam bebatuan karang dan jenis Isognomon ephippium ditemukan menempel di batu karang, jenis substrat sendiri memiliki substrat berlumpur dan berpasir yang bercampur batu karang. Di beberapa stasiun seperti stasiun II dan IV ini ditemukan aktivitas beberapa nelayan. Terdapat beberapa kelong di sekitaran stasiun (Tabel 1). Tabel 1. Parameter Lingkungan Perairan PARAMETER I II III IV KETERANGAN Notji, 2007 dalam Andri, Henky, Arief, 2015, kisaran suhu dianggap Suhu 29,90oC 28,90oC 31,90oC 28,9oC layak bagi kehidupan organisme akuatik adalah 2,70oC – 3,20oC. Derajat Tjutju (2009) Nilai yang ideal untuk Keasaman 8,33 8,35 8,38 8,36 kehidupan antara 7 – 8,5. (pH) Menurut (KMNLH, 2004 dalam Oksigen 7.2 7.4 7.7 7.5 Saraswati, Arthana, Hendrawan, Terlarut mg/L mg/L mg/L mg/L 2017) nilai DO yang baik untuk (DO) biota laut, yaitu >5 mg/L. 44 E-ISSN: 2685-8827 Jurnal Manajemen Riset dan Teknologi Universitas Karimun (JURNAL MARITIM) Vol. 2 No. 1. Agustus 2020 3.2 Klasifikasi dan Morfologi Kerang 3.2.1 Kerang Tridacna Crocea Klasifikasi Kingdom : Animalia Filum : Mollusca Kelas : Bivalvia Ordo : Cardiida Klasifikasi Family : Cardiidea Cangkang besar dengan panjang Kerang sekitar 15 cm, Genus : Tridacn dengan lebar sekitar 20 cm, dengan panjang lingkaran ke seluruhanya sekitar 55 cm di temukan kedalaman sektar 30 Sumber: Mey, (2019) - 80 cm. 3.2.2 Kerang Pitar tumens Klasifikasi Kingdom : Animalia Filum : Mollusca Kelas : Bivalvia Ordo : Venerida Family : Veneridae Klasifikasi Genus : Pitar Panjang maksimal kerang pitar tumens adalah 5-6 cm. Panjang umum untuk jenis kerang ini adalah 4 cm. Perairan Sumber: Mey, (2019) Indonesia banyak dijumpai dengan ukuran 4-6 cm. 3.2.3 Kerang Anadara antiquate Klasifikasi Kingdom : Animalia Filum : Mollusca Klas : Bivalvia Ordo : Arcida Klasifikasi Family : Arcoidea Genus : Anadara Ukuran panjang A. antiquata saat pertamakali matang gonad berkisar antara 20,7–22,1 mm,. A.antiquata mampu Sumber: Mey, (2019) menghasilkan 1652000 butir/induk/pemijahan. 3.2.4 Kerang Fragum Unedo Klasifikasi Kingdom : Animalia Filum : Mollusca; Klas : Bivalvia Ordo : Cardiida; Klasifikasi Family : Cardiidae; Warnanya putih krem dengan sisik merah stroberi dan Genus : Fragum memiliki cangkang keras, berusuk kuat dengan punggung Sumber: Mey, (2019) yang ditandai di satu sisi. 45 E-ISSN: 2685-8827 Jurnal Manajemen Riset dan Teknologi Universitas Karimun (JURNAL MARITIM) Vol. 2 No. 1. Agustus 2020 3.2.5 Kerang Ruditapes decussatus Klasifikasi Kingdom : Animalia Filum : Mollusca; Kelas : Bivalvia Ordo : Venerida; Klasifikasi Family : Veneridae; Genus : Ruditapes Kerang Ruditapes dapat terkubur hingga kedalaman 15-30 cm di pasir dan pot, menahan fase pasang surut di Sumber: Mey, (2019) kedalaman. Sifon dipisahkan satu sama lain 3.2.6 Kerang Perna Perna Klasifikasi Kingdom : Animalia Filum : Mollusca; Kelas : Bivalvia Ordo : Mytilida; Klasifikasi Family : Mytilidae; Kerang Perna memiliki anatomi dengan Panjang tubuh Genus : Perna antara 6,5 – 8,5 cm dan diameter sekitar 1,5 cm. Organ yang terdapat dalam kerang adalah ginjal, jantung, mulut, Sumber: Mey, (2019) dan anus. 3.2.7 Kerang Anadara Granosa Klasifikasi Kingdom : Animalia Filum : Mollusca Kelas : Bivalvia Ordo : Arcoida Klasifikasi Family : Arcidae Hewan ini gemar memendam dirinya de dalam pasir atau Genus : Anadara lumpur dan tinggal di mintakat pasang surut. Dewasanya Sumber: Mey, (2019) berukuran 5 sampai 6 cm panjang dan 4 sampai 5 cm lebar. 3.2.8 Kerang Donax trunculus Klasifikasi Kingdom : Animalia Filum : Mollusca; Kelas : Bivalvia Ordo : Cardiida; Klasifikasi Family : Donacidae; Cangkang kecil kosong memiliki ukuran (15 hingga 25 Genus : Donax mm) Hewan-hewan yang hidup sering terlihat di mana ombak mencuci pasir di bagian paling dangkal zona littoral Sumber: Mey, (2019) ketika tingkat pasang surut berubah. 46 E-ISSN: 2685-8827 Jurnal Manajemen Riset dan Teknologi Universitas Karimun (JURNAL MARITIM) Vol. 2 No. 1. Agustus 2020 3.2.9 Kerang Pitar citrinus Klasifikasi Kingdom : Animalia Filum : Mollusca Kelas : Bivalvia Ordo :Venerida Klasifikasi Family : Veneridae Cangkang berukuran kecil sampai sedang; cangkang tidak Genus : Pitar terlalu tebal dan berat; cangkang berwarna luar krim pekat, ukuran yang didapatkan: 4 – 5 cm; habitat: hidup membenamkan diri di dalam
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