Teratology and Early Fish Development

SYNOPSIS. The developing teleost embryo is a highly complexand balanced physico-chemical system in equilibrium with itsenvironment. Even slight alterations of the external aquaticenvironment, or a pathochemical modification of the immediatematernal environment, may lead to developmental modifications.Multiple malformations produced as a result of metabolism ofteratogens and interacting factors are similar to syndromesobtained by hybridization. Modifying factors, although possessingsome specificity as to intracellular targets are nonspecificas to the types of anomalies produced in most instances. Embryonic responses to teratogens occur at various developmentalstages and at different levels of organization, modifying thenormal development. Intracellular molecular syntheses and sensitivemetabolic targets essential for normal development may be blockedor modified, and rates of differentiation and growth affected.Embryo-sensitivity and resistance is related to tolerance leveland regulatory capacity. The terata observed have been correlatedwith molecular mechanisms and disorganization with disruptionsof cellular contacts and translocatory yolk cytoplasmic movements. Causality as it pertains to early teleost aberrant developmentis reviewed, and suggestions for research and an extensive bibliographyof the relevant literature provided.