Introduction
Sturgeons in Eurasia are under increased pressure of extirpation and, as a result ex situ measures including the safeguarding of remaining genetic heterogeneity and supporting the recovery of the populations in the wild, are essential.
Since it is widely accepted that the targets and rearing practices between commercial rearing and conservation rearing do differ substantially in terms of fitness, this presentation attempts to describe those practices using three study cases in comparison with commercial sturgeon aquaculture. The Adriatic sturgeon (A. naccarii), the American or Baltic sturgeon (A. oxyrinchus), and the European sturgeon (A. sturio) all are critically endangered and face the threat of (local extinction) in the recent past. The three species currently are subject to regional restoration programs that differ substantially with regard to the organization of the recovery projects.
Materials and Methods
The analysis will summarize and compare the approaches taken, experiences made and the results obtained in an attempt to emphasize practicable yet safe results for the restoration programs. The analysis comprises not only rearing practices but also looks more deeply into the administrative background, the strategic approaches taken, the solutions for establishing ex situ stocks as well as rearing and release programs, funding and regional integration.
Results and Discussion
Since Adriatic and European sturgeon recovery programs were established in the 1980s based on the remaining populations of the species in the Po and Gironde rivers, the prerequisites differed from the reintroduction of the Baltic sturgeon that was extirpated when the project came to life. All three projects established captive (ex situ) broodstocks in an attempt to save the species from extinction and to provide a basis for the subsequent reproduction and release of the offspring. The comparison addresses the strategic and administrative background of the projects, analyzing the involvement of governmental agencies in funding and in accompanying the process of the recovery/reintroduction.
The means of broodstock development, reproduction and rearing are investigated and the practices of the releases are compared from the technical as well as from the administrative point of view. The strengths and weaknesses of the projects are illustrated and discussed.
As such, the presentation aims at providing a baseline for the planned follow up discussion to identify the options for a closer collaboration between commercial farms and recovery projects. The essential prerequisites, the benefits and the drawbacks in the framework of such a strategic collaboration as well as the possible options for its implementation will be assessed.