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Seasonal environmental changes and fish catch assessment in International Institute for Tropical Agriculture Lake, Ibadan, Nigeria
Abstract
The study assessed environmental variables that affect fish catch in International Institute for Tropical Agriculture lake Ibadan. Some climatic factors and water quality parameters were monitored for 24 months (January 1998 to December 1999).
A total annual rainfall of 794.2mm and 1648mm were recorded in 1998 and 1999 respectively. There was a significant difference (p<0.05) in annual rainfall in 1998 and 1999. The readings in the dry season and rainy season varied from 28.0oC and 27.5oC in 1998 to 27.7oC and 26.6oC in 1999. The highest humidity (87%) occurred in July 1998. The dissolved oxygen (DO) level in IITA lake during this study varied between 6.0 and 8.6mg/l. The seasonal observation of water temperature did not show significant difference (p<0.05) between wet season and dry season in 1998 and 1999. The water pH ranged between 6.7 and 7.8. It was observed that seasonal variation in the water level affected fish catch in the gill nets. It was recommended that commercial fishing should be intensified in dry season to optimize catch per unit effort and hence increase in return from effort.
Journal of Environmental Extension Vol.4 2003: 3-7
A total annual rainfall of 794.2mm and 1648mm were recorded in 1998 and 1999 respectively. There was a significant difference (p<0.05) in annual rainfall in 1998 and 1999. The readings in the dry season and rainy season varied from 28.0oC and 27.5oC in 1998 to 27.7oC and 26.6oC in 1999. The highest humidity (87%) occurred in July 1998. The dissolved oxygen (DO) level in IITA lake during this study varied between 6.0 and 8.6mg/l. The seasonal observation of water temperature did not show significant difference (p<0.05) between wet season and dry season in 1998 and 1999. The water pH ranged between 6.7 and 7.8. It was observed that seasonal variation in the water level affected fish catch in the gill nets. It was recommended that commercial fishing should be intensified in dry season to optimize catch per unit effort and hence increase in return from effort.
Journal of Environmental Extension Vol.4 2003: 3-7
