The Spatial and Temporal Variations of Ichythyofauna and Water Quality in the Crocodile River (East), Mpumalanga, South Africa

M. I. Soko^1*, T. Gyedu-Ababio²

¹Department of Water and Sanitation, Nelspruit, South Africa.
²Inkomati-Usuthu Catchment Management Agency, Nelspruit, South Africa.

DOI: 10.4236/jwarp.2015.73013                

Abstract

The Crocodile River is situated in the north east of the Republic of South Africa. It is a large river basin with a total length of 320 km and draining a catchment of 10,450 km². The water quality of this river is of high importance in sustaining the people and businesses relying on the sustainability of the river. The aim of the study was to use fish and water quality data to determine the present ecological state of the river and identifying the possible sources of pollution in the river. Multivariate statistical analysis was used to identify the main contaminants in the river at the various sections of the river. The results obtained indicated that species richness and diversity are high during low flow condition and the lower reaches had high species richness and diversity compared to the middle and upper reaches. The Fish Response Assessment Index indicated that the Ecological Class for the Crocodile River is mostly at C class beginning from the Kwena Dam downstream. Water quality constituents such as total dissolved solids and electrical conductivity increase with the increase in river distance in the downstream reaches. It was evident from this study that anthropogenic activities along the Crocodile River play a role in water quality deterioration and the subsequent distribution of fish during high and low flow conditions. The main sources of the pollution are believed to be agricultural activities in the upper reaches and a combination of industrial, domestic and agricultural activities in the middle and lower reaches of the Crocodile River.

Keywords

Fish, Water Quality, Nutrients, Anthropogenic Activities, Pollution

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	May, A.M., Mutasem, E., Mark, D.S. and John, L.N. (2006) Factors Influencing Development of Management Strategies for the Abou Ali River in Lebanon I. Spatial Variation and Land Use. Journal of the Science of Total Environment, 362, 15-30. http://dx.doi.org/10.1016/j.scitotenv.2005.09.079
[2]	Ashton, P.J., Hardwick, D. and Breen, C.M. (2008) Changes in Water Availability and Demand within South Africa’s Shared River Basins as Determinants of Regional Social-Ecological Resilience. In: Burns, M.J. and Weaver, A., Eds., Exploring Sustainability Science: A Southern African Perspective, Stellenbosch University Press, Stellenbosch, 279-310.
[3]	Gibert, C.S. and Wendy, A.T. (2003) Watershed Scale Assessment of Nitrogen and Phosphorus Loadings in the Indian River Lagoon Basin. Environmental Management, 67, 363-372. http://dx.doi.org/10.1016/S0301-4797(02)00220-7
[4]	Kunwar, P.S., Anirita, M. and Sarita, S. (2005) Water Quality Assessment and Apportionment of Pollution Sources of Gomti River (India) Using Multivariate Statistical Technique—A Case Study. Analytica Chimica Acta, 538, 355-374. http://dx.doi.org/10.1016/j.aca.2005.02.006
[5]	Parsons, R. and Jolly, J. (1994) The Development of a Systematic Method for Evaluating Site Suitability for Waste Disposal based on Geohydrological Criteria. Report No. TT 67/94, Water Research Commission, Pretoria.
[6]	DWAF (Department of Water Affairs And Forestry) (2004) Internal Strategic Perspectives, Inkomati Water Management Area. Report No. P WMA 05/000/00/0303. No.1, Department of Water Affairs and Forestry, Pretoria.
[7]	Roux, J., Kempster, P.L., Kleynhans, C.J., Van Vliet, H.R. and Du Preez, H.H. (1999) Integrating Stressor and Response Monitoring into a Resource-Based Water-Quality Assessment Framework. Environmental Management, 23, 15-30. http://dx.doi.org/10.1007/s002679900165
[8]	Karr, K.R. and Chu, E.W. (1997) Biological Monitoring and Assessment: Using Multimetric Indexes Effectively. EPA 235-R97-0001, University of Washington, Seattle.
[9]	Kleynhans, C.J. (1999) The Development of a Fish Index to Assess the Biological Integrity of South African Rivers. Water SA, 25, 265-278.
[10]	Kleynhans, C.J. (2008) River EcoClassification. Manual for EcoStatus Determination. Module D: Fish Response Assessment Index (FRAI). Report No TT332/08, No. 2, WRC, Pretoria.
[11]	Holmquist, J.G., Schmidt-Gengenbach, J.M. and Yoshioka, B.B. (1998) High Dams and Marine-Freshwater Linkages: Effects on Native and Introduced Fauna in the Caribbean. Conservation Biology, 12, 621-630. http://dx.doi.org/10.1046/j.1523-1739.1998.96427.x
[12]	March, J.G., Benstead, J.P., Pringle, C.M. and Scatena, F.N. (2003) Damming Tropical Island Streams: Problems, Solutions, and Alternatives. Bioscience, 53, 1069-1078. http://dx.doi.org/10.1641/0006-3568(2003)053[1069:DTISPS]2.0.CO;2
[13]	Bonner, T.H. and Wilde, G.R. (2000) Changes in the Canadian River Fish Assemblage Associated with Reservoir Construction. Journal of Freshwater Ecology, 15, 189-198. http://dx.doi.org/10.1080/02705060.2000.9663736
[14]	Minckley, W.L., Marsh, P.C., Deacon, J.E., Dowling, T.E. and Hendrick, P.W. (2003) A Conservation Plan for Native Fishes of the Lower Colorado River. Bioscience, 53, 219-234. http://dx.doi.org/10.1641/0006-3568(2003)053[0219:ACPFNF]2.0.CO;2
[15]	Quinn, J.W. and Kwak, T.J. (2003) Fish Assemblage Changes in an Ozark River after Impoundment: A Long-Term Perspective. Transaction of the American Fisheries Society, 132, 110-119. http://dx.doi.org/10.1577/1548-8659(2003)132<0110:FACIAO>2.0.CO;2
[16]	Gorman, O.T. and Karr, J.R. (1978) Habitat Structure and Stream Fish Communities. Ecology, 59, 507-515. http://dx.doi.org/10.2307/1936581
[17]	Ferreira, M. (2005) A Study into the Anthropogenic Impacts Affecting the Elands River, Mpumalanga. MSc Thesis, University of Johannesburg, South Africa.
[18]	Heath, R. and Claassen, M. (1999) The Use of Indigenous Fish Species for the Determination of Pesticide and Heavy Metal Loads. Report No 428/1/99, Water Research Commission, Pretoria.
[19]	KNP (Kruger National Park) (2014) Information about the Crocodile River. http://www.winchestermarketing.com/ngwenya/index.php?pgid=3&sid=2