Kepadatan, Pola Distribusi dan Pola Pertumbuhan Kepah (Polymesoda erosa) di Perairan Estuari Karang Gading Kabupaten Deli Serdang, Sumatera Utara.

Abstract

Mangrove ecosystems are complex ecosystems consisting of flora and fauna. P. erosa is a filter feeder animal as well as a suspension feeder that lives at the bottom of the water and immerses itself in muddy substrates. Crabs are often found in the waters of the Karang Gading Estuary, Deli Serdang Regency, North Sumatra. The high activity of the fishing community in the waters of the Karang Gading Estuary by taking the clams continuously can lead to decrease it’s populations as well as the resource of the clams in the waters of the Karang Gading Estuary. This study aims to analyze the density, the distribution pattern and the growth pattern of P. erosa clams, as well as to analyze the relationship of aquatic physico-chemical factors with the density of P. erosa clams in the waters of the Karang Gading Estuary, Deli Serdang Regency, North Sumatra. Sampling points were determined by using the Purposive Sampling method with 3 stations. The measurement of the physico-chemical factors of the waters carried out was temperature, salinity, pH, light penetration, C-organic content, DO and BOD5. The density of clams was analyzed by looking at the number of clams and compared among the area of the plot, the distribution pattern of clams determined by using the morisita index, the growth pattern of clams by measuring the length and wet weight of clams and the correlation analysis between density and chemical physics properties of the waters by using SPSS version 26.00. The results of the study show that the density of clams range from 14,898 to 23,319 ind/m2, the distribution pattern range from 3.06 to 3.16 which means that the distribution pattern of clams as grouped. The value of constant b is less than 3 which means it has a negative allometric clam growth pattern. The results of the correlation analysis find that temperature, salinity, C-organic content, DO and BOD5 have unidirectional and positive influence on the density of clams, while pH and light penetration are not unidirectional and negative.