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Periodical article |
Title: | Long-term Trends in Coral Reef Fish Yields and Exploitation Rates of Commercial Species from Coastal Kenya |
Authors: | Kaunda-Arara, B. Rose, G.A. Muchiri, M.S. Kaka, R. |
Year: | 2003 |
Periodical: | Western Indian Ocean Journal of Marine Science |
Volume: | 2 |
Issue: | 2 |
Pages: | 105-116 |
Geographic term: | Kenya |
Discipline: | Environment |
Subjects: | Fisheries Reef - coral |
Abstract: | Analysis of long-term (1978-2001) marine fisheries data showed that Kenyan coralreefs produced an estimated 2-4 metric t/km2/year of demersal fish. A rapid overall decline in landings occurred during the 1990s. Yields (t/km2/year) showed bimodal peaks in 1982 (2.98) and 1991 (2.90). The average total landings dropped by 55% during the last decade following peak landings in 1982. Landings of the commercially important families (e.g., Siganidae, Lethrinidae, Lutjanidae and Serranidae) declined by about 40% during the last decade, with the groupers (Serranidae) showing the steepest (72%) decline. Analysis of landings per administrative district showed a 78% decline in the densely populated Mombasa district between the periods 1983-1991 and 1992-2001. The less populated districts have registered stable (e.g., Kilifi) to increasing (e.g., Kwale) catches over time. An autoregressive moving average (ARIMA) model forecast of landings predicted a gradual decline in catches during the next decade (2002- 2011) with a trend slope of -0.01 t/km2. Length-frequency analysis for the commercially important species indicated above optimum exploitation (E) and fishing mortality (per year) rates for the sky emperor, Lethrinus mahsena (E = 0.64; F = 2.48) and lower but strong rates for the emperor, L. sangueinus (E=0.51; F=0.93). The more abundant and commercially important whitespotted rabbitfish, Siganus sutor, showed equally strong rates (E= 0.56; F = 1.44/year). A precautionary approach in the management of Kenya\'s coral-reef fisheries is recommended. (Journal Abstract). |