A Concept of Growth in Fishes

Abstract

The use of size as a basic determinant of growth rate is discussed and compared to analogous situations described in literature on other physiological rates. Ecological opportunity and physiological opportunity are visualized as the two interacting components that determine growth, both of which are entered at "threshold" sizes. The parabolic function,[Formula: see text]is developed into a growth equation for linear dimensions and its application explored and discussed using steelhead trout and chinook salmon as an example. Significant differences in growth rate are found between life history types and sexes. The chinook data are then treated on a lt+1, lt plot and it is shown how an apparent fit of the von Bertalanffy type growth equation can result from selectivity of fishing for the larger fish of any brood year. Two lines of research are indicated. (1) The independent measurement of the exponent x through study of size-specific metabolic rates, and (2) the relationship between total mortality rate and growth rate. Without this knowledge a satisfactory synthesis of growth rate into a yield equation cannot be achieved.

Correlated contemporary evolution of life history traits in New Zealand Chinook salmon, Oncorhynchus tshawytscha

“…A relationship between growth or size and age at maturation has been recognized in fishes, including Chinook salmon, for decades (for example, Parker and Larkin, 1959) and has often been depicted in a threshold framework (for example, Myers and Hutchings, 1986;Thorpe et al, 1998). Although terminology has sometimes varied, the central premise is that size or growth function as proximate 'liability' cues to determine the physiological decision to mature at some evolutionarily determined threshold.…”

The Effect of Age on Growth-Resumption in Fish (Lebistes) Checked by Food Restriction

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The size and growth of fish are controlled by the "ecological opportunity" (Parker and Larkin, 1959) available to them in terms of food, space, and other factors, and by the "physiological oppor tunity" resident in the individual fish at that time. Fish kept small by adverse circumstances are able to resume growth when the ecological opportunity offers; in particular, underfed fish, though mature, can grow actively after long periods of restriction if the food supply is increased.

We have studied the effects of age on the growth capacity of female guppies {Lebistes), kept small by scanty feeding for periods up to 1300 days, and then allowed to grow: they were drawn from the colony which is being kept for long-term age/mortality studies, as previously described {Comfort and Doljanski, 1958).

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Integrating dynamic energy budget (DEB) theory with traditional bioenergetic models

“…Qualitative examination of the intraspecific variations in life-history traits shows that the observed patterns are also well reproduced. The observation that fast-growing individuals migrate back to the river to spawn at an earlier age and smaller size than slow-growing individuals (Parker and Larkin, 1959) is well reproduced. Quantitatively, preliminary simulation results for chinook broadly agreed with experimental studies on chinook growth and development rates, but further work is required on fecundity patterns.…”