Age and growth determination of Lower Danube sturgeon species Huso huso and Acipenser stellatus

Abstract

Abstract In the Lower Danube, sturgeon populations have declined dramatically in recent decades. Although efforts have been made at the legislative level since 2006, by forbidden commercial fishing, an assessment of stocks and conservation status of sturgeon species has not yet been made [1]. In this context, it is necessary to estimate the age and growth rate of sturgeon species in order to establish their current conservation status, with a high level of confidence. This article presents the long-term results obtained by INCDPM during 6 years of research in which were captured and released 108 specimens of beluga (Huso huso) and 193 specimens of stellat sturgeon (Acipenser stellatus). Thus, before the ultrasonically tagging of the sturgeon specimens, informational volumes regarding the biometric parameters were collected simultaneously with the gender determination [1]. Based on the collected data and the calculus hypotheses, it was possible to determine the ages of the sturgeon specimens and to perfect the method of improving the confidence level of the data obtained from the in-situ investigations. In order to foster sustainable management of Danube sturgeon populations, it is essential to carry out assessments with a high degree of confidence of the age of anadromous sturgeon species. The quantification of the population depends on species spawning cycles taking into account that they are characterized by high longevity.