8142

• UCREFRP Catalog Number: 8142
• Author: Horn, M. J.
• Title: Nutritional Limitation of Recruitment in the Razorback Sucker ‎(
• USFW Year: 1996.
• Copyright Material: NO

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can have substantially different feeding histories. Further, length is only an indicator of
past growth history, not an indicator of current conditions. Comparing masses of similar-
sized fish may provide additional clues to their condition relative to each other. Mass is a

more transient indicator of growth, exhibiting short-term changes depending on

reproductive condition, immediate feeding history, and stress. Proximate analysis of

body composition, particularly lipids, further provides an early indicator of stress.

Changes in quantity of reserves such as lipids may be observed prior to any observed

decreases in growth following short-term change in food supply (Rice et al. 1993).

Energy reserves can furthermore change substantially without affecting overall weight in

fish. This relationship occurs because water content and lipid content are inversely

related. A fish gains lipids it loses water and thus may incur no net weight change though

available energy reserves have increased dramatically (Flath and Diana 1985; Brown and

Murphy 1991). Lipids may prove particularly useful in analysis of larval fishes because

reserves are limited and tend to be used rapidly. Due to differences in how each metric

(length, mass, lipids) respond to feeding history the relationship among them can be used

as a measure of general well-being (Carlander 1977; Wege and Anderson 1978).

The relationship between length and weight is described by the allometric

function:

W = aLb
,

where W is weight, L is length, and a and b are constants. Logarithmic transformation
results in the equation:

10gW = loga + blogL ,