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Full Length Research
Paper
Spatial distribution of
saline water and possible sources of intrusion into a
tropical freshwater lagoon and the transitional effects on
the lacustrine ichthyofaunal diversity
B. E. Emmanuel and L. O. Chukwu
Department of Marine Sciences, Faculty of Science, University
of Lagos, Akoka, Lagos, Nigeria.
*Corresponding author. E-mail:
monetemi@yahoo.com, beeunilag@gmail.com.
Accepted
18 March, 2010 |
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The spatial distribution of saline water and possible sources
of intrusion into Lekki lagoon and transitional effects on
the lacustrine ichthyofaunal characteristics were studied
during March 2006 and February, 2008. The water quality
analysis indicated that salinity has drastically increased
recently in the lagoon (0.007 to 4.70%). This study has
identified three possible sources for saline water
intrusion, beyond the seasonal input from the two adjacent
lagoons (Lagos and Mahin), salt water intrusion by
subsurface flow through the barrier beach from the ocean,
and leaching of ions through lagoon bottom sediments. Eighty
one fish species belonging to 40 families, 56 genera and 14
orders encountered were mostly freshwater, euryhaline and
marine species adapted to life in the lagoon. The shell fish
included the freshwater prawns Macrobrachium spp and
the portunid crab Callinectes amnicola. This high
number of fish species recorded from Lekki Lagoon in this
study has confirmed the fact that this lagoon is a
transition area between brackish water (Lagos Lagoon and
Mahin Creek) and freshwater (Rivers Saga and Oshun).
Key
words:
Spatial distribution, saline water, lacustrine,
ichthyofaunal, diversity. |
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