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Please use this identifier to cite or link to this item: http://hdl.handle.net/1834/2124

Title: A Comparison Of Condition Factor And Gonadosomatic Index Of Sardine Sardinops Sagax Stocks In The Northern And Southern Benguela Upwelling Ecosystems, 1984–1999
Authors: Van der Lingen, C.D.
Kreiner, A.
Fréon, P.
ASFA Terms: Abstracts
Sardine fisheries
Issue Date: 2001
Publisher: Department of Environmental Affairs and Tourism
Citation: South African Journal Marine Science, 23. p. 123-134
Abstract: Time-series of condition factor (CF) and gonadosomatic index (GSI) were generated using general linear models (GLM) for sardine Sardinops sagax stocks in the northern and southern Benguela ecosystems over the period 1984–1999. During this period the biomass of sardine in the northern Benguela remained at relatively low levels of <500 000 tons, whereas that of southern Benguela sardine increased 40-fold to 1.3 million tons. The GLMs explained 27 and 45% of the observed variation in CF, and 32 and 28% of the observed variation in GSI, for sardine in the northern and southern Benguela subsystems respectively. Whereas the sardine CF in the northern Benguela remained stable over time, that for the southern Benguela stock declined steadily during the study period. Sardine CF showed a seasonal cycle in the southern but not in the northern Benguela. Time-series of GSI showed high interannual variability but no trends in either subsystem, and the seasonal pattern was similar for both stocks. The lack of coherence between the CF time-series for sardine in the two subsystems further suggests that sardine stocks in the northern and southern Benguela subsystems are independent.
URI: http://hdl.handle.net/1834/2124
Related document: http://www.ajol.info/viewarticle.php?id=28120
ISSN: 1814-232X
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