Life History Assessments of Fishery Resources as Applied in Biodiversity Valuation and Conservation In: ICAR Sponsored Winter School on Recent Advances in Fishery Biology Techniques for Biodiversity Evaluation and Conservation, 1-21 December 2018, Kochi.

In fisheries biology, life history parameters of fishes are routinely assessed as they can be employed to understand the dynamics of the resource and aid in fisheries management. Species inhabiting different environments will have the life history characteristics suitable for that particular ecosystem. In this, the principle of natural selection operates which ensures that maximum number of fittest individuals survive and flourish in that particular ecosystem. The relation between habitat, ecological strategies and population parameters give rise to an organism classified as either an r strategist or K strategist (Adams, 1979). The theory of r and K selection is based on two important assumptions. Firstly, the fitness of the offspring is positively related on the resources invested on it and secondly, there is only a fixed and limited amount of resources available. The best reproductive strategy is therefore a compromise between these two conflicting demands and determines the species position on the r-k continuum. The r- k continuum is a model and the r or k selection of any species is not in an absolute sense but only on a relative basis with reference to other species, and useful for comparison in an ecological context. Fisheries based on more r selected species will be more productive and can be fished at younger ages and higher levels of fishing mortality than k selected species. Also, provided there is a minimum population size and a spawning stock, their chances of recovery from overfishing are higher. Fisheries based on more K selected species will have a high maximum yield per recruit but fewer fish