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Title: Effect of heavy metals on the biological activities of marine fishes, with special reference to their reproduction and development
Author: Mohammed Nagib, F. J. B.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1988
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Oogenesis is examined in two rockling species. Seven developmental stages are described in Ciliata mustela L. and six stages in Gairdropsarus mediterraneus L., since both species were collected at the same time, suggesting the possibility of an earlier spawning in the first species. Ultrastructural differences in the zona radiata occur, monopartite in G. mediterraneus and bipartite and double thickness in C. mustela. Cortical alveoli are first formed in the cortex originating from Golgi vesicles. Ultrastructural evidence suggests that protein yolk formation has a contribution from both exogenous and endogenous sources while lipid yolk is solely endogenous. The endogenous protein is synthesised by Golgi complexes. Lipid yolk is formed in close association with rough endoplasmic reticulum in G. mediterraneus and annulate lamellae in C. mustela suggesting that both organelles play a role in lipid formation. Fertilised eggs of Clupea harengus L. were exposed to different acid pHs. Egg, perivitelline space, and yolk volumes were measured in relation to osmoregulation. The effect of acid on the morphology of the hatched larvae was also demonstrated. Jaw, branchial and skeletal abnormalities were observed. Exophthalmus condition was recorded in these larvae. Acid water causes epidermal necrosis, degeneration of the chloride cells, and swelling of the membrane-bound structures of the trunk muscle tissue at the ultrastructural level. The study demonstrates that aluminium is extremely toxic at pH 5.0 causing 99.52% cumulative mortality to C. harengus eggs. Ultrastructural and morphometric evidence show that aluminium causes disruption and swelling in the cell membranes of the brain and muscle tissues of C. harengus larvae accompanied by degeneration of mitochondrial cristae. Such effects would reduce the metabolic activity and survival potential of these larvae with subsequent consequences on recruitment success of the stock.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available