Spatial and temporal segregation of Labeobarbus species migrating to Arno-Garno River
Contenu principal de l'article
Résumé
The spawning migration of Labeobarbus species of Lake Tana to Arno- Garno River was studied from July to December 2010. Five sampling sites, based on the nature, velocity of the flowing river, human interference and suitability for fish spawning were selected by preliminary survey. Fish were sampled monthly in the non-peak spawning season (July, November and December) and bimonthly in the peak spawning season (August to October) using 6, 8, 10, 12 and 14 cm stretched mesh size gillnets. A total of 1077 Labeobarbus specimens were collected. Labeobarbus intermedius, L. brevicephalus, L. nedgia and L. tsanensis were the dominant species,contributing 93.03% of the total catch. The monthly gonad-somatic index indicated that the spawning season for Labeobarbus species was from August to October. Labeobarbus intermedius and L. tsanensis were the first species to aggregate at the river mouth starting from July and L. brevicephalus and L. nedgia aggregate starting from September. However, L. intermedius was the first to migrate to the upstream sites starting from the end of July followed by L. tsanensis. The last migrant species was L. brevicephalus starting from the fourth week of August. Pair-wise comparison of the Labeobarbus spp. showed temporal segregation in all sampling months, except L. intermedius and L. brevicephalus that did not show temporal segregation with L. nedgia. The best management option to protect these species is closed season that should be strictly implemented during the spawning season (from June to October).
Details de l'article
Ce travail est disponible sous licence Creative Commons Attribution - Pas d’Utilisation Commerciale - Partage dans les Mêmes Conditions 4.0 International.
Comment citer
##plugins.generic.shariff.share##
Références
Abebe Ameha (2004). The effect of birbira, Milletia ferruginea (Hochst.) Baker on some Barbus spp. (Cyprinidae, Teleostei) in Gumara River (Lake Tana), Ethiopia. MSc. Thesis, Addis Ababa University.
Abebe Getahun, Eshete Dejen, and Wassie Anteneh (2008). Fishery studies of Ribb River, Lake Tana Basin, Ethiopia. A report submitted to World Bank. Vol. 2:1573.
de Graaf, M. (2003). Lake Tana’s piscivorous Barbus (Cyprinidae, Ethiopia): Ecology, Evolution, Exploitation. PhD. Thesis, Wageningen University, Wageningen, The Netherlands.
de Graaf, M., Machiels, M. A. M., Wudneh, T., and Sibbing, F. A. (2004). Declining stocks of Lake Tana’s endemic Barbus species flock (Pisces; Cyprinidae): natural variation or human impact? Biological Conservation, 116, 277–287.
de Graaf, M., Nentwich, E. D., Osse, J. W. M., and Sibbing, F. A. (2005). Lacustrine spawning, a new reproductive strategy among ‘large’ African cyprinid fishes? Journal of Fish Biology, 66, 1214–1236.
Dgebuadze, Yu. Yu., Mina, M. V., Alekseyev, S. S., and Golubtsov, A. S. (1999). Observations on reproduction of the Lake Tana barbs. Journal of Fish Biology, 54, 417–423.
Dixon, B., Nagelkerke, L.A.J., Sibbing, F.A., Egberts, E., and Stet, R.J.M. (1996). Evolution of MHC class II chain-encoding genes in the Lake Tana barbell species flock (Barbus intermedius complex). Immunogenetics, 44, 419-431.
Kornfield, I., and Carpenter, K.E. (1984). Cyprinids of Lake Lanao, Philippines: taxonomic validity, evolutionary rates and speciation scenarios. In: Evolution of fish species flocks, Echelle AA, Kornfield I (Eds), Orono press, Maine, pp. 69-83.
Kruiswijk, C. P., Hermsen, T., van Heerwaarden, J., Dixon, B., Savelkoul, H. F. J., and Stet, R. J. M. (2002). Different modes of major histocompatibility class Ia and class IIb evolution in the Lake Tana African ‘‘large’’ barb species flock. In Evolution of Major Histiocompatibility Genes in Cyprinid Fish, Molecular Analyses and Phylogenies (PhD thesis, Kruiswijk, C. P), pp. 77–116. Wageningen: Cell Biology and Immunology Group, University of Wageningen.
Lowe-McConnell, R. (1975). Fish Communities in Tropical Freshwaters: their Distribution, Ecology, and Evolution. Longman, London, 337 pp.
Nagelkerke, L.A.J. (1997). The barbs of Lake Tana, Ethiopia: morphological diversity and its implications for taxonomy, trophic resource partitioning and fisheries. PhD thesis, Agricultural University Wageningen, The Netherlands.
Nagelkerke, L.A.J., and Sibbing F.A. (1996). Reproductive segregation among the large barbs (Barbus intermedius complex) of Lake Tana, Ethiopia. An example of intralacustrine speciation? J. Fish. Biol. 49, 1244–1266.
Nagekerke, L.A.J., and Sibbing, F.A. (2000). The large barbs (Barbus spp., Cyprinidae Teleostei) of Lake Tana (Ethiopia), with a description of a new species, Barbus ossensis. Neth J. Zool. 2:179–214.
Nagelkerke, L.A.J., Sibbing, F.A., Boogaart, J.G.M. vanden, Lammens, E.H.R.R., and Osse, J.W.M. (1994). The barbs (Barbus spp.) of Lake Tana: a forgotten species flock? Environ. Biol. Fish., 39, 1-22.
Nelson, J. S. (1994). Fishes of the World. Wiley: New York. Pp. 234.
Ogutu-Ohwayo, R. (1990). The decline of the native fishes of Lakes Victoria and Kyoga (East Africa) and the impact of introduced species, especially the Nile Perch, Lates niloticus and the Nile tilapia, Oreochromis niloticus. Envi. Biol. Fish 27, 81–96.
Palstra, A. P., de Graaf, M., and Sibbing, F. A. (2004). Riverine spawning in a lacustrine cyprinid species flock, facilitated by homing? Animal Biology, 54, 393–415.
Reyntjes, D., Tesfaye Mengistu, Tesfaye Wudneh, and Palin, C. (1998). Fisheries development in Ethiopia–which way now? European Union Bulletin 11 (1), 20–22.
Sibbing, F.A., and Nagelkerke, L.A.J. (2001). Resource partitioning by Lake Tana barbs predicted from fish morphometrics and prey characteristics. Rev. Fish Biol. Fish., 10, 393-437.
Skelton, P. H., Tweddle, D., and Jackson, P. (1991). Cyprinids of Africa. In: Cyprinid Fishes, Systematics, Biology and Exploitation (Winfield, I. J. and Nelson, J. S., eds), pp. 211–233. London: Chapman and Hall.
Tomasson, T., Cambray, J. A., and Jackson, P. B. N. (1984). Reproductive biology of four large riverine fishes (Cyprinidae) in a man-made lake, Orange River, South Africa. Hydrobiologia 112, 179–195.
Wassie Anteneh, Abebe Getahun, and Eshete Dejen (2008). The lacustrine species of Labeobarbus of Lake Tana (Ethiopia) spawning at Megech and Dirma tributary rivers. SINET: Ethiop. J. Sci.