Kondisi habitat ikan pelangi arfak, Melanotaenia arfakensis Allen, 1990 di Sungai Nimbai, Prafi Manokwari

Abstract

This research aimed to describe habitat condition of endemic arfak rainbowfish, Melanotaenia arfakensis at Sungai Nimbai on June-July and September-October 2012. The study site consisted of seven sampling stations for organisms and environmental qualities, from upstream to downstream segment, and each of these stations divided into two habitat types, ie. slow littoral and run areas. The parameters of habitat quality were measured and analysed such as current water, temperature, dissolved oxygen, pH, grease and oil concentration, riparian vegetation, macroinvertebrates composition and abundance, also fish composition and distribution. Riparian vegetation sampling was done at stream sides using 4 m2 plot for seedling and 400 m2 for sapling, pole, and tree categories. Macroinvertebrate and fish at two habitat types were collected using surber of 0.0625 m2 and hand net. The result showed that arfak rainbow-fish were only found at upstream segment. The presence of the species was related to physical and chemical parameters condition that supporting their life, also related to the availability of spawning and nursering habitat for larvae, and the aquatic insects as their food. The absence of the fish at downstream segment, maybe due to the degradation of their habitat condition that related to decreasing riparian vegetation coverage and organic waste flow to stream system, and also the presence of alien fish. The study showed decreasing of the quality and suitable habitat areal for this endemic species decrease, therefore it is need to conserve the natural habitat as the effort to maintain the sustainability of this species populations.