In this study, the population structure, growth parameters and condition of chub, Squalius squalus, from the Assino Creek, a tributary of the River Tiber, were investigated. A total of 1311 specimens were caught monthly from March 2008 to May 2009 by electrofishing. Total length (TL ± 0.1 cm) and weight (W ± 0.1 g) were recorded; age estimation was based on scalimetry and sex was determined by macroscopic observation of the gonads. Age composition ranged from 0+ to 11+. Total length varied from a minimum of 4.1 cm to a maximum of 48.8 cm, for a weight of 0.5 g and 1233.0 g, respectively. Length-weight regression was log10W = −2.201 + 3.127 log10 TL for males and log10W = −2.273 + 3.190 log10 TL for females. Previous growth was determined with back-calculation from scale measurements using the non-linear Body Proportional Hypothesis. Theoretical length growth was estimated with von Bertalanffy’s model. Condition was evaluated by relative weight. In Italy there are few available data about the biology of Squalius squalus: the aim of this study was therefore to fill this lack of information by investigating some important aspects of the growth of the population in Assino Creek.
Age and growth analysis of the chub Squalius squalus (Bonaparte, 1837), in the Assino creek (Umbria, Italy)
POMPEI, LAURA;CAROSI, Antonella;PEDICILLO, GIOVANNI;LORENZONI, Massimo
2011
Abstract
In this study, the population structure, growth parameters and condition of chub, Squalius squalus, from the Assino Creek, a tributary of the River Tiber, were investigated. A total of 1311 specimens were caught monthly from March 2008 to May 2009 by electrofishing. Total length (TL ± 0.1 cm) and weight (W ± 0.1 g) were recorded; age estimation was based on scalimetry and sex was determined by macroscopic observation of the gonads. Age composition ranged from 0+ to 11+. Total length varied from a minimum of 4.1 cm to a maximum of 48.8 cm, for a weight of 0.5 g and 1233.0 g, respectively. Length-weight regression was log10W = −2.201 + 3.127 log10 TL for males and log10W = −2.273 + 3.190 log10 TL for females. Previous growth was determined with back-calculation from scale measurements using the non-linear Body Proportional Hypothesis. Theoretical length growth was estimated with von Bertalanffy’s model. Condition was evaluated by relative weight. In Italy there are few available data about the biology of Squalius squalus: the aim of this study was therefore to fill this lack of information by investigating some important aspects of the growth of the population in Assino Creek.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
