ABSTRACT
The objective theme of this book is to comprehensively elucidate the negative effects of anthropogenic activity on skewing of sex ratio in fi shes by disruption of sex differentiation process and impaired reproductive output through precocious sexual maturity and consequent decline in recruitment. More than 98% fi shes are gonochores (Pandian, 2011, p. 18), and are divided into (i) primary and (ii) secondary gonochores. The remaining 2% fi shes are hermaphrodites, and in them, sexuality ranges from simultaneous to sequential and serial hermaphroditism (see later). Sex is a luxury and a system, where two individuals are required for reproduction, frequently involving sexually selected traits and complicated courtship behavior leading to mating (Schultheis et al., 2009). Hence it costs time and energy but ensures recombination to generate genetic diversity (see Pandian, 2012, p. 17). The reproductive strategy of fi shes seems to sustain and increase reproductive success and/or genetic diversity rather than to maintain the Mendelian sex ratio of one female to one male.
