Aging in fish

Abstract

Theories on aging are well advanced but empirical data lag far behind them mainly because few fish populations are unexploited and are allowed to reach old age. There is more evidence supporting the theory of genetic aging controlled by a biological clock than aging by random damage, but the two are probably interconnected. Growth and natural mortality are closely correlated between and within species and populations. Fast growth and early maturity curtail the life-span; slow growth and late maturity have the reverse effect. There appears to be a trade-off between reproductive effort and longevity to ensure the production of the maximum number of progeny over the life-span of the mature adults. This trade-off is influenced by a feedback system dependent on reproductive success. Genetic control of growth and thus mortality is not well understood and is obscured by environmental factors. Anatomical and physiological changes with age are similar to those of mammals and include the appearance of malignant tumors. Changes in growth and natural mortality have an important influence on yield and recruitment in fisheries. The understanding of aging processes lies in an improved knowledge of bioenergetic processes and the environmental factors that control them.