Distribution, Abundance and Age Cohorts of Phorcus Turbinatus (Gastropoda) In Eastern Libya’s Mediterranean Sea (Published)
Distribution of Phorcus turbinatus along the littoral zones of Al-Haneah and Susah, eastern Libya’s Mediterranean Sea, at day, at low tide, was studied using belt transects with quadrates. P. turbinatus in both sites inhabited only the lower rocky littoral, many times in aggregates in tidal pools. P. turbinatus was absent in the mid and the upper rocky littoral, all the sandy shores, and the sublittoral. The abundance was maximum just above the shoreline (209 and 207 individuals/m2 in both sites), and decreased on moving up the littoral. Factors controlling the distribution were discussed. P. turbinatus showed no size gradient on moving upwards from the shoreline to the upper littoral. Frequency distribution of “height of shell from base to the apex” (HBA) indicated that P. turbinatus populations of both study sites exist in three age cohorts. Mean HBA of cohort 1 and 2 in Al-Haneah was 7 and 15mm, mean HBA of cohort 3 could not be determined; in Susah, HBA of cohorts 1 and 2 were 6 and 11.8mm.
Keywords: Abundance, Distribution, Monodonta turbinata, Phorcus turbinatus, age cohort.
Survey of Zooplanktondiversity and Abundance and Its Relationship with Physicochemical Parameters in River Kashimbila Takum, Taraba State, Nigeria (Published)
Zooplankton diversity and abundance and its relationship with physico-chemical parameters in River Kashimbila was carried out for a period of eight (8) months from August, 2016 to March, 2017.Physico-chemical parameters were determined, the identification and abundance of zooplankton were also determined. A total of twenty one (21) species of zooplankton were reported, which was dominated by Ciliophora (34.61%), followed by Rotifera (32.92%) and the least being Cnidaria (0.02%). Shannon Weinner diversity index ranged from 1.40 -2.72, Margalef Index from 2.37 – 2.72 and evenness from 0.45 – 0.60. The data revealed that there was a significant difference among number of species and species count at (P<0.05) between raining and dry season. Zooplankton diversity and abundance were influenced by seasons and sites while species composition varied significantly with season at (P<0.05).Based on the zooplankton diversity and abundance, the rivers holds high possible impact on fish production.
Keywords: Abundance, Diversity, River Kashimbila, Zooplankton