Status of the breeding populations of terns (Sternidae) along the eastern coast of Saudi Arabia following the 1991 Gulf War

Peter Symens and Abdullah H. Alsuhaibany

A b s t r a c t: During four successive summers following the 1991 Gulf War oil spill, the breeding activities of the tern populations on the coral islands off Saudi Arabia were monitored closely to assess the impact of the spill on these birds and to address their conservation needs. On average each summer, nearly 70,000 pairs of terns bred on these islands, representing approximately 65 % of all terns in the entire Saudi Arabian Gulf. In 1991 the breeding terns were relatively unaffected by the oil spills. However, in 1992 and 1993 there was a significant decline in the terns' breeding success due to a lower average clutch size and hatching success, a reduced chick growth rare and higher chick mortality, an increase in inter- and intraspecific piracy, and a lower nest attendance resulting in a significant increase in chick predation. All these factors indicated an acute shortage of food. Several studies suggested that a failure in fish stock recruitment had occurred in 1991 as a direct result of the impact of the oil spill on fish eggs and larvae. The high breeding success in 1994 indicated a significant increase in food abundance and also that there had been no long-term impact of the oil spill. The presence of oil-fouled adult terns on the colonies throughout the study period and the occurrence of a new oil spill on Karan in 1994 indicate that chronic oil pollution represents a continuous threat for the marine environment of the northern Gulf.

BASSON, P.W., BURCHARD, J.E., HARDY, J.T. & PRICE, A.R.G. 1977. Biotopes o/the western Arabian Gulf 284 pp. Dhahran, ARAMCO.
BIBBY, C.J., BURGESS, N.D. & HILL, D.A. 1992. Bird Census Techniques. London, Academic Press.
BUNDY, G., CONNOR, R.J. & HARRISON, C.J.O. 1989. Birds of the Eastern Province of Saudi Arabia. London, Witherby.
BULLOCK, I.D. & GOMERSALL, C.H. 1981. The breeding populations of terns on Orkney and Shetland in 1980. Bird Study 28: 187-200.
CAIRNS, D.K. 1987. Seabirds as indicators of marine food supplies. Biological Oceanography 5: 261-271.
CARPENTER, K.E. 1991. A Preliminary Report on the Effects of the Gulf Crisis on Fisheries. Unpublished report to FAO, Rome. CRAMP, S. (ed.) 1985. The Birds o/the western Palearctic, Volume 4. Oxford, Oxford University Press.
CROXALL, J.P. & ROTHERY, P. 1990. Population regulation of seabirds and implications of their demography for conservation. In: Bird Population Studies: Their Relevance to Conservation and Management. Pertins, C.M., Lebreton, C.D. & Hirons, G.M. (eds). Oxford, Oxford University Press.
DANCHIN 1992. Food shortage as a factor in the 1988 Kittiwake Rissa tridactyla breeding failure in Shetland. Ardea 80: 93-98.
DENNIS, R. 1991. Arabian Gulf Oil Spills. March 1991. Unpublished report to ICBP and NCWCD.
DRENT, R.H. & DAAN, S. 1980. The prudent parent: energetic adjustments in avian breeding. Ardea 68: 225-252.
EVANS, M.I. 1994. Important Bird Areas in the Middle East. BirdLife Conservation Series No.2. Cambridge, BirdLife International.
EWINS, P.J. 1985. Growth, diet and mortality of Arctic tern Sterna paradisaea chicks in Shetlans. Seabird 8: 59-68.
FREEDMAN, B. 1989. Environmental Ecology, the Impacts of Pollution and Other Stresses on Ecosystem Structure and Function. San Diego, Academic Press.
FURNESS, R.W. & BIRKHEAD, T.R. 1984. Seabird colony distributions suggest competition for food supplies during the breeding season. Nature 311: 655-656.
GALLAGHER, M.D., SCOTT, D.A., ORMOND, R.F.G., CONNOR, R.J. & JENNINGS, M.C. 1984. The distribution and conservation of seabirds breeding on the coasts and islands of Iran and Arabia. In: Status and Conservation of the World's Seabirds. Croxall, J.P., Evans, P.G.H. & Schreiber, R.W. (eds). Cambridge, ICBP Technical Publication No.2: 421-456.
HENNEMAN, B. 1991. The Gulf War Oil Spills: The ICBP Survey of the Saudi Arabian Gulf Coast, March 1991. Unpublished report to ICBP and NCWCD.
IMO 1993. Final Report o/the Persian Gulf Oil Pollution Disaster Fund. 74 pp. London, International Maritime Organization.
LEWIS, S.J. & MALECKI, R.A. 1984. Effects of egg oiling on larid productivity and population dynamics. Auk 101: 584-592.
MATHEWS, CP., KEDIDI, S., FITA, N.I. & AL-YAHAY, A. 1992. Preliminary Assessment of the Effects of the 1990-1991 Gulf War on Saudi Arabian Prawn Stocks. Unpublished Report to FAO.
MCCAIN, J.C. & HASSAN, M. 1993. Assessment of ichthyoplankton in Saudi Arabian Gulf waters before and after the 1991 Gulf oil spill. Arabian Journal of Science and Engineering 18 (2): 269-291.
MONAGHAN, P., UTTLEY, J.D. & BURNS, M.D. 1992. Effects of changes in food availability on reproductive effort in Arctic terns Sterna paradisaea. Ardea 80: 71 -81.
MONAGHAN, P., UTTLEY, J.D., BURNS, M.D., THAINE, C. & BLACKWOOD, J. 1989. The relationship between food supply, reproductive effort and breeding success in Arctic terns Sterna paradisaea. Journal of Animal Ecology 58: 261-274.
MONTEVECCHI, W.A. 1993. Birds as indicators of change in marine prey stocks. In: Birds as Monitors of Environmental Change.
Furness, R.W. & Greenwood, J.J.D. (eds). London, Chapman & Hall.
NELSON, B. 1980. Seabirds, their Biology and Ecology. London, Hamlyn Publishing Group.
PEARCE, E 1993. Gulf fisheries still suffering in the wake of war. New Scientist 1865 (20 March 1993).
PRICE, A.R.G. 1992. The Gulf War 1990-1991: Effects on fisheries and other marine systems. Marine and coastal Areas 1.

ROSE, P.M. & SCOTT, D.A. 1994. Waterfowl Population Estimates. IWRB Publication 29. Slimbridge, International Waterfowl and Wetlands Research Bureau.
SYMENS, P. & EVANS, M.I. 1993. Impact of Gulf War oil spills on Saudi Arabian breeding populations of terns Sterna in the Arabian Gulf, 1991. Sandgrouse 15: 18-36.
UTTLEY, J., MONAGHAN, P. & WHITE, S. 1989. Differential effects of reduced sandeel availability on two sympatrically breeding species of tern. Ornis Scandinavica 20: 273-277.
WHILDE, A. 1985. The 1984 all-Ireland tern survey. Irish Birds 3: 1-32.
WHITE, D.H., KING, K.A. & COON, N.C. 1979. Effects of no. 2 fuel oil on hatchability of marine and estuarine bird eggs. Bulletin of Environmental Contamination and Toxicology 21: 7-10.
ZWARTS, L. 1987. Birds and other key species. In: Saudi Arabia: An Assessment of Biotopes and Coastal Zone Management Requirements for the Arabian Gulf. Unpublished Report. Jeddah, MEPA.