World Journal of Fisheries & Aquaculture Sciences Research
Vol. 2, No. 1, May 2016
Table of Contents
Authors: Jegede, T. and Akinsorotan, A. M.
Static bioassay was conducted to determine the 96h median lethal level (LC50) of 2-[(Phosphonomethyl) amino] acetic acid on Heterobranchus biborsalis juveniles (4.90 ± 0.13 g and length of 5.02 ± 1.0 cm respectively) and to describe the histological changes in the gill and liver. LC50 of H. bidorsalis fingerlings was determined graphically as 18.07 mg/ L-1. Fish displayed the following behaviors respiratory distress (hyperventilation), erratic swimming, jumping out of the tank at higher concentration, molting, discolouration, hyperventilation, irregular operculum opening and tail beat frequencies, loss of reflex and settling of the experimental fish at the bottom of the aquaria at higher concentration. Also fish mortality at varying concentrations increased with increasing concentration of glyphosate herbicides. Histological examination revealed mild degeneration in the gill architecture, artropy of the filament artery, distorted lamellar epithelium, epithelia proliferation/erosion of gill filaments and lamellae and necrosis of the gill cells. The liver showed no noticeable lesion at lower concentration of 2-[(Phosphonomethyl) amino] acetic acid, slight degeneration and vacuolation of the hepatocyte, evidence of inflammation of the liver cells with cellular infiltration of hepatocellular parenchyma and evidence of fatty acid degeneration and severe hepatic damage as a result of hepatotoxicity of 2-[(Phosphonomethyl) amino] acetic acid. Copyright © WJFASR, all rights reserved.
Key words: 2-[(Phosphonomethyl) amino] acetic acid, glyphosate, Heterobranchus bidorsalis, histology
Authors: Kamalu C.I.O, Anusi M., Kamen F.L.,Okwara C.A, Nwakaudu M.S, Ekeke I,
In this work, Experimental results were monitored for a period of eight months on certain variables parameter in great Ruguma eutrophication site with Fugro International Laboratory to observe the profiles of the simultaneous variations of these parameters with time. Some parameters show the approach or eminence of hypereutrophication. Cox et al (2009) model for recovering from hypereutrophication was modified to accommodate phosphate concentration variation in the great Ruguma hypereutrophication. Numerical values of constraints, initial and boundary conditions were culled in from the works of Cox et al (2009) in solving the system of ODEs modified.From the analysis made on the results obtained, the Great Ruguma Seasonal Ponds may be said to be recovering from hypereutrophication.The findings of this work can be applied in any trophic study especially when it is entering or recovering from hypereutrophication. Copyright © WJFASR, all rights reserved.
Keywords: Modeling, dynamics of hypereutrophication, Great Ruguma Seasonal Ponds, biomass, oxygen, ammonium, phosphate.
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