Pakistan Journal of Marine Sciences, Vol.20(1&2), 75-85, 2011.

Abstract

Tidal induced variation in the distribution, abundance and diversity of mesozooplankton along the Karachi coast, Pakistan
Farah Naz1, Naureen Aziz Qureshi2, Noor Us Saher1
1. Center of Excellence in Marine Biology, University of Karachi, Karachi 75270, Pakistan
2. Department of Zoology, Government College, University Faisalabad,
Allama Iqbal Road, Faisalabad 3800, Pakistan.
Abstract.-Temporal variations in biomass, abundance, diversity and species composition of mesozooplankton in relation to the tidal state were studied. Mesozooplankton sampling was carried out twice at the ebb and flood tides at fixed stations closed to Phitti creek (P) and Manora channel (M) near the Karachi coast during February 1999. The average percent abundance of mesozooplankton was high at ebb tide i.e. 66% and 63% whereas low on flood tide i.e 34% and 37%, at both stations respectively. However, there were no differences in species composition with tidal fluctuations at both sites. The mesozooplankton community was typically composed of 22 a group of which copepod was the most abundant group (comprising % of the total zooplankton) at both sites. During the flood tide high diversity 0.11 ± 0.021 was observed in Phitti creek, but no difference was observed at Manora channel. The species richness was high (2.30 ± 0.01273 and 2.38 ± 0.502) in Manora channel both ebb and flood tides, respectively, whereas the dominance values were high at Phitti creek. Complete randomized design ANOVA showed that there was no significant difference in abundance of mesozooplankton between stations and tides nested in stations, but the difference was significant for the diversity and equitability. On the short temporal scale the tidal cycle additionally determines changes in the zooplankton composition.
Key words: Zooplankton, Distribution, Abundance, flood and ebb tide.