STURGEONS = BLACK SEA TREASURE
STURGEON FISHING DYNAMICS IN THE ROMANIAN SECTOR OF THE BLACKSEA, BETWEEN 1970-2002 (FAO, 2002)
STURGEON FISHING DYNAMICS IN THE BLACK SEA, BETWEEN 1991-2000(FAO, 2002)
PLEADINGFOR THE DEVELOPMENT OF MARICULTURE INROMANIA
Pro and Againts Arguments - requirements and constraintsExposureWavesDepthCurrentsrentsPollutionlutionFactorMax. temperaturtemperatureGoodpartialAverageshelteredbadexposedRomaniaexposed≤1 1 m From 1 to 3 m ≥3 3 m > 3m> 30 m From 15 to 30 m < 15 m ≥15 mstrongabsentmoderatelowweakhighstrongFom 22 to 24ºC From 24 to 27ºC > 27ºC from24 to 27ºCTemperatura min. 12ºC 10ºC
AIMS AND BACKGROUNDObject: RUSSIAN STURGEON Acipenser gueldenstaedti (Brandt & Ratzeberg, 1833)Why?As a consequence of the alteration of sturgeons habitat, it was decided to introducethem (including the Russian sturgeon) in 1998 in the Appendix II list of the UnitedNation’s Convention on International Trade of Endangered Species of Wild Faunaand Flora (CITES).After the sterlet, it has the tastiest flesh (16% fats), being commercialized andconsumed fresh (portioned, filé), refrigerated (portioned, filé), frozen (portioned,filé), salted, smoked (filé), canned, and the eggs are consumed fresh or preserved.The global capture of Russian sturgeon, starting with 1991, has been continuouslydropping, which determined special measures for their protection and preservationSturgeon aquaculture can contribute to the preservation of natural populationsthrough repopulation and providing meat and caviar for the market without theexploitation of natural stocks. The main species used in aquaculture are the pallidsturgeon, beluga, Russian sturgeon, starry sturgeon and the bester .
EXPERIMENTSThe biological material used in the experiments was obtained through artificial breeding,carried out in a private fresh water farm and is represented by Russian sturgeon juvenilesaged about 6 months. The passage to marine pontic water was made gradually, through acontinuous slow debit flow of marine water. The farming was carried out during a period of 11months.
EXPERIMENTSExperimental base: cages (freshwater and marine water), exterior basins,interior basins
RESULTS AND DISCUSSIONSThe values of the physico-chemical parametres of the water in the Russian sturgeonfarming cages (marine and fresh water) (limits - October 2007 - August 2008)The farming environment Marine water Fresh waterParameterT o C 6 - 26 2 - 28Salinity PSU 11,87 - 16,66 0,45 - 0,60pH 8,0 – 8,2 8,5 - 8,7O 2cm 3 /l 4,88 – 8,28 6,11 – 9,41O 2% 115,9 – 148,1 120 - 140Org. Subst. mgO 2 /l 0,06 – 3,55 3,36 – 8,06P-PO 4mg/l 0,08 - 0,040 0,018 – 0,006Si-SiO 4mg/l 0,139 - 0,367 0,56 – 1,193N-NO 3mg/l 0,078 - 0,904 0,102-0,533N-NO 2mg/l 0,005 – 0,041 0,003 – 0,016N-NH 4µg/l 0,036 - 0,627 0,053 –0,078
RESULTS AND DISCUSSIONSFeed:Adler Aqua Danish origin pellets were used, with an energetic value of 4 915 kcal/kg,with the following content: proteins: 45%, carbohydrates: 15%, fibers: 2,5 %,Phosphor: 1 %, Vitamin A – 2 500 IE/kg, Vitamin D3 - 500 IE/kg, Vitamin E + tocoferol- 15 mg/kg, Ethoxyquin - 100 mg/kg. The food was distributed daily, divided into 1-2meals/ kg, in a percentage of 3-5% the body mass of the fish.The coefficient of food conversion was similar for the two farming environments:1,35 for marine water and 1,40 for fresh water.Survival: 100% for fresh and marine water.
RESULTS AND DISCUSSIONSI. Comparison regarding the experimental conditions:• a lot farmed in cage - fresh water (climatic conditions characteristic forthe Romanian littoral): 10 individuals/mc, 80 g/piece• a lot farmed in cage – marine water (climatic conditions characteristicfor the Romanian littoral): 10 individuals/mc, 80 g/piece
RESULTS AND DISCUSSIONSThe body mass increase of the Russian sturgeon farmed in fresh and marinewater on the Romanian littoral
RESULTS AND DISCUSSIONSThe length increase of the Russian sturgeon farmed in cages placed inmarine and fresh water
Correlation between the biometric characteristics
RESULTS AND DISCUSSIONSII. Comparison regarding the vital space:- the comparative experimental farming, in cages and in basins, with acontinuous flow of marine water, with the same density and the same foodratio: 10 individuals/mc: 10 individuals in a 1 mc cage and 60 individuals in a 60mc basin; the experiment was carried out between April and August. Animalscoming from the same experimental lot were used, they received the same typeof food, distributed in the same percentage (3-5% of the body mass).
RESULTS AND DISCUSSIONSThe growth of the body mass of the Russian sturgeon farmed in basin and in cage(marine water)
RESULTS AND DISCUSSIONSThe length growth of the Russian sturgeon farmed in basin and cage (marine water)
Correlation between the biometric characteristics(marine water)
Fresh waterDISEASESHemorragic Bacterial Septicemyproduced by the Aeromonas - A. hydrophilaand Pseudomonas - P. flurorescens genera.Marine waterMarine Fish Vibriosis produced byVibrio anguillarum and Vibrio spp.The Bacterial Gill Disease is an infectiousdisease with a secondary character, causedby bacterial germs of the Cytophaga genus.
CONCLUSIONS• The experiments carried out between October and Augusthad as its aim the comparative farming of 4 months oldRussian sturgeon juveniles in fresh and marine water.• Under the climatic conditions of the Romanian littoral, theexperiments revealed the fact that the growth parametersof the Russian sturgeon in marine water are superior tothose regarding the farming in fresh water.• In addition, the animals that had a larger vital space(concrete basin) grew faster than those farmed in cages, thedifference being more obvious as far as the body mass isconcerned.• Our experiments represent a pleading for the developmentof the marine aquaculture on the Romanian littoral!
AcknowledgmentsThe experiments carried out in the period 2007-2008, in theframe of the national project (CEEX Agral contract nr.7/2005focused on the marine fishery management).THANK YOU VERY MUCH FOR YOUR ATTENTION!