KEBIASAANMAKAN DANBIOLOGI REPRODUKSI IKANMOTAN (Thynnichthys polylepis) DIWADUK KOTOPANJANG, RIAU

Abstract

Ikan motan (Thynnichthys polylepis) merupakan jenis ikan yang mempunyai nilai ekonomi yang cukup penting di Kabupaten Kampar. Ikanmotan diWaduk Kotopanjang termasuk jenis ikan yang dominan dan digemarimasyarakat. Penelitian ini untuk mendapatkan data dan informasi mengenai kebiasaan makan dan biologi reproduksi dilakukan pada bulan Agustus sampai Nopember 2009. Penelitian ini dilakukan melalui metode survei dengan pengambilan contoh dilakukan secara purposive sampling. Untuk mengetahui kebiasaan makan digunakan metode Indeks Preponderan, kematangan gonad diamati secara morfologi dan penentuan fekunditas dihitung dengan metode
gravimetrik. Hasil penelitian inimenunjukan bahwa ikan motan tergolong jenis ikan herbivora dengan pakan utama makrofita 49,9%, pakan pelengkapnya adalah phytoplankton 22,6% dan detritus 17,4%, dan pakan tambahan terdiri atas protozoa 0,8%, rotifera 0,5%, dan crustaceae 0,4%. Selain itu makanan yang tak teridentifikasi 8,4%. Ikan motan memijah secara bertahap (parsial) dimulai pada bulan Nopember. Fekunditas ikan motan berjumlah antara 25.360-61.198 butir dengan diameter telur pada kisaran antara 0,31-0,90mm, serta indeks kematangan gonad antara 6,65-17,56%.

Motan (Thynnichthys polylepis) is one of fish species having the economically important value in Kampar Regency. In Kotopanjang Reservoir motan is a kind of fish which is dominant and it is liked by the people. The objectives of the research were to get data and information of food habit and the biology reproduction such as gonadal maturity, fecundity, and egg diameter has been carried out on August to November 2009. The research is done with the survey method, meanwhile the samples taken by purposive sampling. Food habit can used an index of preponderance method, the gonadal maturity is used by the morphology, meanwhile fecundity is counted by gravimetric. The result of the research shows that motan is belong to a herbivore fish with a mean food macrophyta of 49.9% as a mean food, phytoplankton of 22.6% and detritus of 17.4% as complement food. Meanwhile the addition food such as protozoa of 0.8%, rotiferas of 0.5%and crustaceae of 0.4%. Beside that, the unidentify part is 8.4%. Motan spawning by partial which is started on November. Fecundity of motan shows that the total egg varied between 25,360-61,198 with egg diameter is between 0.31-0.90 mm. Meanwhile index maturity of gonads is between 6.15-17.56 %. Based on the aspects some water quality.