Habitat selectivity of fresh water fishes of two second-order tropical streams in Tigray, Northern Ethiopia

Abstract

Background: Habitat selectivity and ecology of freshwater fishes were studied in two selected streams and their junction point which consist a total of 39 microhabitats. The aims of this study were to describe the habitat preference and its availability to fish assemblage, as well as ecology, habitat use, and habitat characteristics. Methods: We collected fish with backpack electrofishing three times during August 2013, December 2013, and March 2014. Using a variation partitioning approach of R software, we studied the relationship of fish abundances with stream type, habitat type, and abundance of key macroinvertebrate taxa. Results: A total of 6554 fishes representing four species belonging to the family Cyprinidae were caught. A higher total fish abundance was recorded from Gereb Tsedo (4870; 74.3%) than from Elala stream (1684; 25.7%). Taking both streams together, the overall total relative fish abundance was significantly higher in pools (53%) than in runs (35%) and in riffles (12%) at P < 0.05. Species-wise comparisons showed that 71%, 15%, 13%, and 1% of the pool fish community were occupied by Garra blanfordii, Garra ignestii, Garra dembecha, and Garra aethiopica, respectively. Stream type, habitat type, and key macroinvertebrate taxa each explained a significant proportion of the variation in fish abundance. Based on the variation partitioning approach, fish abundance was higher in Gereb Tsedo stream (P < 0.01). Moreover, fish abundance increased with pool habitat type (P < 0.01) and with availability of key macroinvertebrate taxa (P < 0.01). Conclusion: Fish abundance differed between stream types, among habitats and among key macroinvertebrate taxa availability. Among the factors, habitat type was the most important driving factor behind variation among fish abundances, and pool supports the highest fish abundance.

ASPEK BIOLOGI DAN HABITAT IKAN LURAI (Corica soborna Hamilton, 1822) DARI HILIR SUNGAI MAHAKAM, KALIMANTAN TIMUR [Biological Aspects and Habitat of Lurai Fish (Corica soborna Hamilton, 1822) from the Lower Mahakam River, East Kalimantan]

“…Belum ada data pembanding yang ditemukan berkaitan dengan habitat ikan lurai di wilayah geografis lainnya. Setiap spesies ikan memiliki preferensi habitat yang unik dan persyaratan habitat untuk setiap tahap siklus hidup ikan (telur, larva, remaja dan dewasa) mungkin juga sangat berbeda dalam badan air yang sama (Tesfay et al, 2019) dan faktor-faktor seperti suhu, pH air, kecepatan arus, ke dalaman air, tipe subtrat dasar, ketersediaan sumber makanan, kecerahan air dapat saling berinteraksi.…”

Microbiological and Physico-Chemical Parameters of the Danube River (Romanian–Bulgarian Sector) with Ichthyofaunal Diversity

“…The fish intestinal tract is considered to be the main portal for pathogens (10,11) and as environmental and ecological factors shape the intestinal tract microbiota (12,13) a correlation between water microbiota and fish diversity is thus consequential. Another factor worth mentioning is that small variations in water pH are also a factor in fish communication and social interaction patterns (14), having important effects on the growth and reproduction of the fish assemblages (15)(16)(17) and as well as on bacterial community composition (8,18).…”