Sex lives of the British freshwater fishes
One of the imperatives of evolutionary success is survival to pass on genes to the next generation. Britain's freshwater fishes exhibit a range of strategies evolved to feed, evade predation and disease and also to breed in the challenging environments they inhabit. This chapter looks at the reproductive strategies of these fishes. Animals in general exhibit a spectrum of reproductive strategies. At one end of the scale are those that produce few fertilised eggs or young and frequently accord them great care in upbringing. At the other is the high fecundity reproductive strategy. As a generalisation, many of Britain's freshwater fishes tend towards the high-fecundity end of the scale, though some groups exhibit parental care. In ecological terms, roach are something of generalists. They have a wide diet, adapting to seasonal availability of food, and are also tolerant of a range of flow conditions and even of low salinity in upper estuaries.