Keanekaragaman dan Distribusi Bivalvia di Pantai Modung, Kabupaten Bangkalan Madura

Pantai Modung merupakan salah satu pantai landai yang berada di pesisir selatan Pulau Madura. Pantai ini memiliki tipe substrat yang kompleks, yaitu sebagian bersubstrat pasir berlumpur, berbatu karang, dan juga beberapa bagian berhutan mangrove sehingga memiliki substrat yang cenderung berpasir. Penelitian ini bertujuan untuk mengkaji keanekaragaman, distribusi, dan pemanfaatan bivalvia di Pantai Modung Madura. Penelitian dilakukan di zona intertidal Pantai Modung, Kecamatan Modung, Kabupaten Bangkalan Madura. Sampel diambil dengan menggunakan metode transek dan koleksi bebas. Di setiap daerah intertidal atas, tengah, dan bawah diambil dua kuadran sampling berukuran 1 m x 1 m. Setelah preservasi, sampel diidentifikasi berdasarkan karakter morfologi. Wawancara dengan penduduk setempat dilakukan untuk mengetahui jenis-jenis bivalvia yang dimanfaatkan oleh penduduk. Data dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa Pantai Modung memiliki keanekaragaman bivalvia yang tinggi, yaitu terdapat 38 spesies bivalvia yang tergolong dalam 15 famili. Bivalvia di Pantai Modung tersebar di daerah intertidal atas, bawah dan tengah. Bivalvia yang terdapat di intertidal atas merupakan bivalvia epifauna, yaitu sebanyak sepuluh spesies. Bivalvia infauna memiliki kemampuan meliang yang berbeda dan ciri taksonomi yang penting untuk mengetahui distribusi vertikal ini adalah kondisi lekuk palial. Sebagian besar bivalvia (82%) yang terdapat di Pantai Modung dikonsumsi oleh masyarakat dan semua bivalvia tersebut tergolong dalam pemakan suspensi. Modung Beach is located at the sourthen shore of Madura. It has complex bottoms, namely mud, muddy sand, and rocky substratum. These kinds of substratum support variety of bivalves. The purpose of this research was to know the diversity, distribution, and economic significance of bivalves in the intertidal zone of this beach. Both of death shells and living specimens were collected and preserved for further identification.  The results revealed that different substratum was occupied by different families of bivalves. Field study were done in intertidal zone by using transect lines method as well as free collection. It was defined three intertidal zone, namely upper, middle, and lower intertidal. All samples were preserved in ethanol 70%. After preservation, samples were indentified based on their morphological characters.  In addition to sampling and identification, interview was done to the local people to know the bivalves that were consumsed by them. Data were analyzed descriptively. The results revealed that there were 38 species of bivalves that belong to 15 families. All of them were distributed in upper, middle, and lower intertidal. Bivalves that occupied the upper zone were epifauna (there were 10 species). Infauna bivalves which were found in the middle and lower zones have different burrowing ability, and these related to their characters of pallial sinus. Pallial sinus is important taxonomic character to know the vertical distribution of bivalves. Majority of bivalves (82%) were consumed by local people, and all of those bivalves were suspension feeder bivalve.