Abstract
Sediment discharges from rivers have a negative impact on coral reef ecosystems. Indicators of coral decline measured in the present study were: (1) injury to living stony corals; (2) soft coral cover; and (3) bare rocky substrate suitable for colonization by corals. The relationship between these indicators and the distribution of terrigenous sediment was studied for the Malindi-Watamu fringing reef complex along the Kenyan coast off East Africa during 1982 and 1983. Decline of this reef had been repeatedly noted during the preceding decade. The influence of terrigenous sediment from the Sabaki River appears to be strongest in the Watamu area in the south and in the northern-most part of the Malindi reef area. Correlations, between each of the above three coral stress response indicators, on the one hand, and quantitative indicators of sediment loading, on the other hand, were not clear. However, a combined coral stress indicator involving all three factors was shown to have a clear relationship with terrigenous sediment loading and provided a rapid means of field evaluation of the effects of sediment stress on stony corals. Values for the combined coral stress indicator were found to increase in proportion to increasing values of terrigenous sediment loads in both study areas. A higher coral stress indicator value means a high proportion of injured or algae infested corals, and/or a high soft coral cover, and/or a high proportion of rocky substrate suitable for, but unoccupied by, living corals.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Belk, M. S., Belk, D. (1975). An observation of algal colonisation on Acropora aspera killed by Acanthaster planci. Hydrobiologia 46: 29–32
Benayahu, Y., Loya, Y. (1977). Space partitioning by stony corals, soft corals and benthic algae on the coral reefs of the northern Gulf of Eilat (Red Sea). Helgoländer wiss. Meeresunters. 30: 362–382
Blom, J., Hagen, H. van der, Hove, E. M. van, Katwijk, M. M. van, Loon, R. van, Meier, N. F. (1985). Decline of the Malindi-Watamu Reef complex. Quantitative and qualitative survey of the coral growth. Report no. 195, Laboratory of Aquatic Ecology, Catholic University, Nijmegen, The Netherlands
Bock, K. R. (1979). Tourism and Kenya's coral reef. Swara 2 (5): 28–34
Brakel, W. H. (1984). Sesonal dynamics of suspended-sediment plumes from the Tana and Sabaki rivers, Kenya: analysis of landsat imagery. Remote Sensing Environ. 16: 165–173
Cortés, J., Risk, M. J. (1984). El Arrecife Coralino del Parque National Cahuita, Costa Rica. Revta Biol. trop. 32: 109–121
Delft Hydraulics (1970). Malindi Bay Pollution II. Field measurements and recommendations. Delft Hydraulics Laboratory, The Netherlands, Report R611
Endean, R. (1976a). Destruction and recovery of coral reef communities. In: Jones, O. A., Endean, R. (eds.) Biology and geology of coral reefs, Vol II. Academic Press, London, p. 215–254
Endean, R. (1976b). Population explosions of Acanthaster planci and associated destruction of hermatypic corals in the Indo-West Pacific region. In: Jones, O. A., Endean, R. (eds.) Biology and geology of coral reefs, Vol II. Academic Press, London, p 389–438
Finn, D. P. (1982). Soil loss in developing countries and its relationship to marine resources: examples from East Africa. Oceans 1982: 942–949
Finn, D. P. (1983). Land use and abuse in the East African region. Ambio 12 (6): 296–301
Giesen, W., Van de Kerkhof, K. (1984). The impact of river discharges on the Kenya coral reef ecosystem — the physical processes. Part II: Effect on the Malindi-Watamu coastal environment. Report no. 194, Laboratory of Aquatic Ecology, Catholic University, Nijmegen, The Netherlands
Gittins, R. (1985). Canonical analysis. A review with applications in ecology. Springer-Verlag, Berlin
Goreau, N. I., Goreau, T. J., Hayes R. L. (1981). Settlement, survivorship and spatial aggregation in planulae and juveniles of the coral Porites porites (Pallas). Bull. mar. Sci. 31: 424–435
Geig-Smith, P. (1964). Quantitative plant ecology. Butterworths, London
Hamilton, H. G. H., Brakel, W. H. (1984). Structure and coral fauna of East African reefs. Bull. mar. Sci. 34: 248–266
Heys, F. M. L., Brouns, J. J. W. M. (1976). Aspects of competition between stony coral (Scleractinia) and other bentic reef organisms. Report no. 84, Laboratory of Aquatic Ecology, Catholic University, Nijmegen, The Netherlands (in Dutch)
Hong, G. A., Sasekumar, A. (1979). The community structure of the fringing coral reef, Cape Rachado, Malaya. Atoll Res. Bull. 244: 1–11
IUCN/UNEP (1985). Management and conservation of renewable marine resources in the eastern African region. UNEP Regional Seas Reports and Studies No. 66, Nairobi, Kenya
IUCN/UNEP (1988). Wells, S. M. (ed.) Coral reefs of the world, Vol. 2. Indian Ocean, Red Sea and Gulf. UNEP, Regional Seas Directories and Bibliographies. IUCN, Gland Switzerland and Cambridge, U.K./UNEP, Nairobi, Kenya
Jones, D. A. (ed.) (1969). Bangor-Watamu Expedition, preliminary report. Univ. Coll., N. Wales
Keech, R., Moore, J., Stafford Smith, M., Green, F. (1979). Preliminary report of the Leopard Reef Expedition. Durham University, Durham, UK
Kinsman, D. J. J. (1964). Reef coral tolerance of high temperature and salinities. Nature, Lond. 202: 1280–1282
Loya, Y. (1976). Effect of water turbidity and sedimentation on the community structure of Puerto Rican corals. Bull. mar. Sci. 26: 450–466
Loya, Y. (1978). Plotless and transect methods. In: Stoddart, D. R., Johannes, R. E. (eds.) Coral reefs: research methods. UNESCO, Paris, p. 197–217
Mann, K. H. (1982). Ecology of coastal waters. A systems approach. Stud. Ecol. 8: 1–322
Roberts, L. (1987). Coral bleaching threatens Atlantic reefs. Unex-plained changes are occurring in some of the most productive ecosystems on the planet, the Caribbean coral reefs. Science, N.Y. 238: 1228–1229
Salm, R. V. (1983). Coral reefs of the western Indian Ocean: a threatened heritage. Ambio 12: 349–353
Samoilys, M. A. (1988). Abundance and species richness of coral reef fish on the Kenyan coast: the effects of protective management and fishing. Proc. 6th int. coral Reef Symp. 2: 261–266 [Choat, J. H. et. al. (eds.) Sixth International Coral Reef Symposium Executive Committee, Townsville]
SAS Institute Inc. (1985). SAS User's Guide: Statistics, version 5 edn. SAS Institute Inc., Cary, North Carolina
Schroeder, J. H., Jacob, K. H., Mägdefrau, G. (1974). Sedimentology of coast and shelf environments. Regional training course, Sept. 16–29 1974, Malindi Kenya. UNESCO Division of Marine Sciences/Technische Universität Berlin (unpublished document)
Schuhmacher, H. (1975). The role of soft corals (Alcyonacea, Octocorallia) in the reef biocoenoses of the Red Sea and the Australian Barrier Reef. 67th Annual Meeting of the German Zool. Society in Bochum. June 1974. Verh. dt. zool. Ges. 67: 380–384
Squires, D. F. (1962). Corals at the mouth of the Rewa River, Viti Levu, Fiji. Nature, Lond. 195: 361–362
Ter Braak, C. J. F. (1987). Ordination. In: Jongman, R. H. G., Ter Braak, C. J. F., Van Tongeren, O. F. R. (eds.) Data analysis in community and landscape ecology. Pudoc, Wageningen, p. 91–173
Thompson, A. O. (1956). Geology of the Malindi area. Rep. geol. Surv. Kenya 36: 1–69
Thurman, H. V. (1978). Introductory oceanography. Merrill Publ. Company, Columbus
UNESCO (1984). Comparing coral reef survey methods. Report of a regional UNESCO/UNEP Workshop of Phuket Marine Biological Centre Thailand, 13–17 December 1982. Rep. mar. Sci. 21: 1–170
Van de Kerkhof, K., Giesen, W. (1984). The impact of river discharges on a Kenya coral reef ecosystem — the physical processes. Part I: The Athi (Sabaki) river basin. Report no. 193. Laboratory of Aquatic Ecology, Catholic University Nijmegen, The Netherlands
Waning, I., Hafkenscheid, M. (1984). The importance of the coral reefs for tourism and imployment in Malindi and Watamu, Kenya: an abstract. Catholic University Nijmegen, The Netherlands
Watermeyer, Legge, Piesold, Uhlman (1981). Athi river basin preinvestment study. For: TARDA (Tana and Athi River Development Authority), Nairobi. Agrar & Hydrotechnik GmbH, Essen
Author information
Authors and Affiliations
Additional information
Communicated by O. Kinne, Oldendorf/Luhe
Rights and permissions
About this article
Cite this article
van Katwijk, M.M., Meier, N.F., van Loon, R. et al. Sabaki River sediment load and coral stress: correlation between sediments and condition of the Malindi-Watamu reefs in Kenya (Indian Ocean). Marine Biology 117, 675–683 (1993). https://doi.org/10.1007/BF00349780
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00349780