Andrzej Kompowski, Zbigniew Neja
Agricultural Academy in Szczecin, Kazimierza Królewicza 3-4, 71-550 Szczecin,
Poland
Key words: Aspius aspius, asp, growth rate, back-calculation, Oder River.
Abstract.
Juvenile specimens of asp (0 age group) were collected in 1996-2001 in canals
of the Międzyodrze with fine-mesh fry seine. Adult specimens were collected
from commercial catches in 1995-2003. The length of fish at which scales began
to appear (SL = 13.81 mm) was determined using the dependence between the number
of sclerites on the caudal part of the scale and the standard length. A similar
result of 13.41 mm was obtained in studies of the dependence between the scale
radius and fry body length. The average lengths in subsequent years of life
were determined by reconstructing the growth rate of the studied fish using
back-calculations from scales. The differences in the growth rate of females
and males were statistically insignificant. The von Bertalanffy growth model
was fitted to the data from the back calculations and the following values were
obtained: L∞ = 75.24 cm; k = 0.165; t0
= 0.224 year; W∞ = 7 463 g. The length-weight dependence
can be described as W = 0.0075 L3.1964. The growth
rate of asp from Międzyodrze waters is average in comparison with that of other
populations of this species.