STUDI KEANEKARAGAMAN DAN KELIMPAHAN IKAN DI DANAU TOBA KECAMATAN BALIGE KABUPATEN TOBA

Abstrak

This study aims to determine the abundance of fish, fish diversity and physical-chemical factors of Lake Toba waters in Balige District, at three different research stations, namely station 1 Pelabuhan Mulia Raja Napitupulu Balige, station 2 Tambunan Sunset Beach, and station 3 Lumban Pea Village. The sampling method was carried out by Purposive Sampling using traps and scoops with three repetitions. The parameters observed included index, abundance, diversity, dominance, uniformity, physical parameters observed included temperature, light intensity, brightness, and current speed, chemical parameters observed included acidity (pH), dissolved oxygen (DO), and Biological Oxygen Demand (BOD). The results showed that there were nine species of fish caught, with Amphilophus labiatus being the most abundant and dominant species. The highest abundance index was the Red devil Amphilophus labiatus species with an average of 28.26% classified as a medium category. The diversity index of station 1 H’= 1.77, station 2 H’=1.76, and station 3 H’=2.01 is classified as medium category. The dominance index at station 3 has the highest value among stations 1 and 2 with a value of C= 0.71 classified as medium category. The uniformity index at the three research stations is E= 0.81 – 0.91 with a high category. The results of temperature measurements are 25°C-28.5°C, light intensity is 1275 -1686 Lux, brightness is 5.3 - 6.5 M, and current speed is 0.20 - 0.40 m/s. The state of chemical factors in the waters of Lake Toba, Balige District, The results of acidity measurement at the 3 research stations are the same, namely 7, DO is 6.4 - 7.2 mg/L, and BOD is 4.6 - 6.7 mg/L. These results indicate that the invasive species Amphilophus labiatus dominates the Lake Toba ecosystem and has the potential to suppress native species.