Acclimation to farm conditions of wild caught sturgeon species as by-catch from the North-West Turkish Black Sea coasts

Abstract

Fisheries Faculty, Mugla University,Ko¨tekli, Mugla, TurkeySummaryThe objective of this study was to investigate the acclimationcondition for by-catch sturgeons taken to farming facilities,monitoring, condition factor and mortality rates of threedifferent sturgeon species (Huso huso, Linnaeus 1758;Acipenser stellatus, Pallas 1771; Acipenser gueldenstaedtii,Brand& Ratzeberk 1758) which were caught along the BlackSea coasts. A total of nine individuals from by-catch of twodifferent sites were used. First site is the mouth of SakaryaRiver (41 07¢N; 30 38¢E; Yenimahalle) which flows to theBlack Sea, and the second was side of Istanbul Bosphorus(41 11¢N; 29 07¢E; Anadolukavagi) in the Black Sea. Theseindividuals were transfered from the catching area to theland by sustenance tank with marine water. Tests to adjustfish from live feed to manufactured feed under captiveconditions were also undertaken. Live food wet feed andmanufactured feed were used in this acclimation experiment.As a live feed tubifex food and earthern worms, as a wet feedchicken liver and minced white meat and as a manufacturedand sturgeon feed were used. Five individuals from threespecies were adapted to the farm conditions and manufac-tured feed in different days. The most sensitive sturgeon wasobserved stellat sturgeon, beluga and Russian sturgeon,respectively.IntroductionSturgeons (Acipenseriformes) are one of the most ancientgroup of the Osteichthyes with 27 species distributed in thetemperate waters of the Northen Hemisphere (Birnstein, 1993).The Black Sea inhabite (Huso and Acipenser) which wereBeluga (Huso huso), sturgeon (Acipenser sturio), Russiansturgeon (Acipenser gueldenstadtii), Stellate sturgeon or Sev-ruga (Acipenser stellatus), Sterlet (Acipenser ruthenus), Ship(Acipenser nudiventris) (Memis, 2007).Environmental pressures, such as water pollution, damconstruction and development of adjacent watersheds forirrigation proposes, which have been responsible for the loss ofspawning grounds, has declined populations and their diverstyis currently threatened due to human influences (Wirgin et al.,1997; Pourkazemi et al., 1999; Vasilev, 1999; Gisbert andWilliot, 2002; Rosenthal et al., 2006).As a result of these declines, all sturgeon species worldwidewere included in Appendix II of the Convention on theInternational Trade of Endangered Species of Wild Fauna andFlora (CITES) regulations on 1 April 1998. This provided aregulatory mechanism for import and export of sturgeon andtheir products helping to control the illegal caviar trade and itsdetriment to wild populations (Mohler, 2003). Turkey also wassigned this convention in 1998. From this date catching of allsturgeon species in Black Sea are forbidden by Ministry ofAgriculture and Rural Affair.The first experiment of controlled propagation of sturgeonwas carried out with 1869 A. ruthenus eggs in 1869. Insubsequent years, insemination and incubation were alsoperformed for some other sturgeon species (Dettlaff et al.,1993).Sturgeon aquaculture can be the only solution to theconservation of wild populations through restocking and byproviding a consistent supply without exploiting wild popula-tions. The main species used in aquaculture productionworldwide are white sturgeon (A. transmontanus), Siberian(A. baeri), Russian sturgeon (A. gueldenstadtii), sterlet(A. ruthenus) and hybrid called bester (beluga female x sterletmale) (Mims et al., 2002).There was six sturgeon species in the Black Sea region ofTurkey. But recently, only three species (A. gueldenstadtii,A. steallatus and H. huso) are still occurring occesionally onsouthern Black Sea coastline. The aim of this study is caught asby-catch different species of sturgeons from Black Sea andIstanbul Bosphorus mouth were adapted to aquaculture_conditions for evaluation as future broodstock management.Materials and methodsIn this study nine specimens of three species (Huso huso,Acipenser stellatus, and Acipenser gueldenstaedtii) were usedfor application to culture conditions in order to built graduallyan initial broodstock. These specimens were from Black Sea(41 07¢N; 30 38¢E) by-catches and from those of the IstanbulBosphorus (41 11¢N; 29 07¢E). All by-catches were transferredto Istanbul University Sapanca Inland Fish AquacultureResearch and Applied Station (SIFARAS) in a 150 L tankusing water from the catch area. Two locations were about 70and 120 km distances from the culture site. Catching locationsand biometric datas of sturgeon were recorded. Every fishwere tagged and named as Russian sturgeon (G1, G2, G3),Stellate sturgeon (S1, S2, S3, S4, S5) and Beluga sturgeon (H1)(Table 2).