Struktur Komunitas Gastropoda di Pantai Nyanyi, Tabanan, Bali

Abstract

This study aimed to identify gastropod species, analyze their community structure, assess water quality conditions, and examine the relationship between gastropod abundance and water quality at Nyanyi Beach, Tabanan, Bali. A descriptive quantitative approach was applied using purposive sampling at five observation points. Samples were collected from 50 quadrats measuring 1 × 1 m during the lowest tide. A total of 273 gastropod individuals were recorded, comprising 12 families, 14 genera, and 22 species. Trochus radiatus had the highest proportion (19%), followed by Trochus ochroleucus (12%) and Bursa ranelloides (10%). The gastropod community was relatively stable, with a moderate diversity index (H’) of 2.19-2.55, a high evenness index (E) of 0.87-0.95, and a low dominance index (C) of 0.09-0.14. Water temperature ranged from 29-30 °C, dissolved oxygen from 5.3-5.6 mg/L, salinity from 33-34 ppt, and pH from 7.31-7.40. Temperature showed the strongest relationship with abundance (R² = 0.1091), followed by dissolved oxygen (R² = 0.084), salinity (R² = 0.0266), and pH (R² = 0.0006). Overall, Nyanyi Beach supported a relatively balanced and stable gastropod community