Potensi Ikan Introduksi Menjadi Ikan Invasif di Perairan Danau Toba Kecamatan Onan Runggu

Abstract

The research about the potential of introduced fishes to be invasive fish in Lake Toba, Onan Runggu District, was carried out from March to May 2021. The purpose of this study was to analyze the diversity of introduced fishes and their potential to become invasive fish and their relationship to water physico-chemical factors. The research was conducted at four sampling stations selected by purposive sampling method based on activities around the station. Fishes samples were taken using nets and then identified, characterized and analyzed for density, relative density, frequency of presence, diversity index, uniformity index, dominance index, and correlation of water physico-chemical factors and density of potentially invasive fish. The results showed that there were five types of introduced fishes. Diversity (H) is low with a value range of 0.4153-0.7573, uniformity (E) is moderate in the range of values 0.2996- 0.5463, and the dominance value (D) at the four stations indicates that there are species that dominate. Based on the characteristics of invasive fish, the introduced fish that has the potential to become an invasive fish is Amphilophus citrinellus. This fish is classified as a carnivorous fish with canine and molariform tooth types and dominates the catch in the four research stations. The physico-chemical factors that strongly influence the density of the fish in the waters are light intensity, light penetration and DO (Dissolved Oxygen), BOD5, Nitrate, and Phosphate.

Penelitian mengenai potensi ikan introduksi menjadi ikan invasif di perairan Danau Toba Kecamatan Onan Runggu telah dilaksanakan pada bulan Maret sampai Mei 2021. Tujuan penelitian ini adalah menganalisis keanekragaman ikan introduksi dan potensinya menjadi ikan invasif serta keterkaitannya terhadap faktor fisika kimia perairan. Penelitian dilaksanakan di empat stasiun yang dipilih dengan metode purposive sampling berdasarkan kegiatan masyarakat di sekitar stasiun. Sampel ikan diambil menggunakan jaring kemudian dilakukan identifikasi, karakterisasi dan analasis, yaitu analisis kepadatan, kepadatan relatif, frekuensi kehadiran, indeks keanekaragaman, indeks keseragaman, indeks dominansi serta korelasi faktor fisika kimia perairan dan kepadatan ikan yang berpotensi invasif. Hasil penelitian menunjukkan terdapat lima jenis ikan introduksi. Keanekaragaman (H) tergolong rendah dengan kisaran nilai 0,4153- 0,7573, keseragaman (E) tergolong sedang pada rentang nilai 0,2996- 0,5463, dan nilai dominansi pada keempat stasiun menunjukkan terdapat spesies yang mendominansi. Berdasarkan karakteristik ikan invasif, ikan introduksi yang berpotensi menjadi ikan invasif adalah Amphilophus citrinellus. Ikan ini tergolong ikan karnivora dengan tipe gigi canine dan molariform serta mendominasi hasil tangkapan dikeempat stasiun penelitian. Faktor fisika kimia yang sangat kuat mempengaruhi kepadatan ikan tersebut di perairan adalah intensitas cahaya, penetrasi cahaya dan DO (Disolved Oxygen), BOD5, Nitrat, dan Fosfat.