The survival and growth performance of hatchlings of clariid catfish hybrid (Clarias gariepinus x Heterobranchus bidorsalis) were examined in two fertilization-based feeding strateies: organic fertilization (ORF) and a combination of organic/chemical fertilization (COC). The study was conducted using six 25-L circular tanks each
having an area of 0.7m2 in a complete randomized design with treatments replicated three times.
The growth performance of Oreochromis niloticus in polyculture with clariid catfishes was studied. The experiment ws designed as two (stocking ratio) by three (species combination) factorial in a completely randomized design. Monoculture of O. niloticus served as the control. Each treatment was replicated three times.
An observation of the rings impressed on the polished sagittae otoliths of Citharinus citharus in the present study revealed reliable age data. Two daily rings were counted on the otoliths. These rings resulted from other factors including growth increments. Two types of rings (periodic and daily) were described. Two periodic rings were counted annually while the daily rings were impressed in multiples of two. Growth increments were also observed on scales.
The algal bioassay technique was used to investigate the effect of Guinness brewery effluent discharged in to the Ikpoba River in Benin City, Edo State of Nigeria. Selenastrum capricornutum Printz and Chlorella vulgaris Bejik were grown in test waters collected from the following point; ‘before the discharge’ of the effluent, the ‘point of discharge’ and the point ‘after discharge’. Mineral nutrients were least at the site `before' discharge than the other two sites.
An investigation into the growth of okra on soil obtained from Oben (SPDC gas flaring site) was undertaken. Seedling emergence, shoot height and leaf area of 28-day old crop sown on soil dug 90 m away from the flare site was significantly reduced when compared to control. Also the activities of amylase, phosphorylase and protease extracted from 5- day old cotyledon were markedly inhibited when the crop was grown on both top and subsoil obtained 90 m from flare site.
