Critique of proportional hypotheses and methods for back-calculation of fish growth

Abstract

Hypotheses which assume a contant proportional deviation of the individual size of fish scales (S) or body (L) from mean size throughout life are biologically insignificant. Growth is considered and illustrated as a complex self-regulating process which continuously changes throughout ontogeny. Speed and form of changes of the growth of individual fish depend mainly on the initial size of the specimen and on the habitat.Consider five main types of changes of the L-S regression lines for individual fish with different initial sizes. They are basically different from the current proportional model of individual growth. The regression lines for individual fish cannot and should not be used for back-calculating L from S either by proportional or by regression methods, as individual L(S)/theoretical L(S) ratio, determined at the time of capture, are usually considerably different, compared to the previous years. For back-calculation of the average L values from average S values the use of separate equations for each age-group or for the whole subpopulation are recommended.

Statistical model of variable allometric growth: otolith growth in Micropogonias furnieri(Actinopterygii, Sciaenidae)

“…Growth of calcareous structures in relation to body size, however, is variable, which results in error in the estimates of backcalculated body length (Fukuwaka & Kaeriyama, 1997). Zivkov (1996) considers that proportional hypotheses do not have a biological meaning, since growth is a complex self‐regulating process, which changes continually during ontogeny, so that adequate equations are necessary for a better description of the process.…”

“…The study of calcareous structures such as otoliths, scales and opercular bones has been important for the determination of the relationship between length and age in fishes, through backcalculation (Casselman, 1990; Francis, 1990). Estimations of length based on annuli spacing, however, can result in significant error if the mathematical model employed is not appropriate for the description of the allometric variation of the structures throughout ontogeny (Campana, 1990; Zivkov, 1996).…”

Compensatory growth in fishes: a response to growth depression

“…Spotted wolffish, Anarhichas minor (Anarhichadidae), displayed compensatory growth after being returned to normal oxygen conditions following 75 days in hypoxic conditions (Foss and Imsland 2002). In other studies, the origin of the reduced growth and the subsequent compensation has not been clear (Zivkov 1982, 1996; Zivkov and Raikova‐Petrova 1991; Nicieza and Braña 1993a,b; Nicieza et al . 1994a).…”

“…Some investigators have made a distinction between ‘nonreal’ and ‘real’ growth compensation (see Zivkov 1982, 1996; Zivkov et al . 1999).…”

Flooded flatheads: evidence of increased growth in Mississippi River Pylodictis olivaris (Pisces: Ictaluridae) following the Great Midwest Flood of 1993

“…We recognize that the Fraser-Lee back-calculation approach that we used has received some scrutiny (e.g., Francis, 1990;Ricker, 1992;Pierce et al, 1996;Zivkov, 1996); however, it has been the technique of choice for many flathead catfish studies (e.g., Mayhew, 1969;Turner, 1977Turner, , 1980Hesse et al, 1978;Lee, 1983;Quinn, 1988;Roell, 1989;Roell & Orth, 1993;Stauffer et al, 1996), and we used it here to facilitate comparison.…”