Introduction to Fish Reproduction
Pollutants may affect an extremely wide range of physiological parameters and manifest their effects at a variety of different loci in the reproductive system. These effects cannot be properly understood without at least a basic understanding of the mechanism by which the endocrine system controls all aspects of reproduction. This Chapter is therefore intended to give the non-specialist a simple introduction to the control of reproduction in the normal teleost fish and to show how such control may be disrupted by environmental pollutants at a multiplicity of sites. It also provides a basic knowledge of endocrine processes which forms the basis for understanding the endocrinology of other glands such as the interrenal and thyroid, as well as showing some of the approaches which can be used to investigate the action of endocrine disrupting chemicals in fish. Since there are over 20,000 species of teleosts, only a small fraction of extant species have been investigated and, since teleost fish occupy a more diverse range of habitats than any other vertebrate, it cannot be expected that a single simple pattern will pertain for all species. Much of the information available therefore comes from the even smaller numbers of species which are of commercial importance, readily available in the geographical areas of the major research laboratories, and easily kept in captivity. Studies of the salmonids (salmon and trout), cyprinids (goldfish and carp), and to a much lesser extent, silurids (catfish) and cichlids (tilapia) thus predominate.
KeywordsEstrogen Cortisol Sewage Prostaglandin Progesterone
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