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Home , Atlantic sturgeon, Lake sturgeon, Milt, Pseudoscaphirhynchus, Roe, Scaphirhynchus

SRAC Publication No. 7200

VI November 2002 PR

Species Profile Production of

Steven D. Mims1, Andrew Lazur2, William L. Shelton3, Boris Gomelsky1 and Frank Chapman4

General Description geons inhabit freshwater, primari- and where the bottom is covered ly in the basin. with stones or gravel. Sturgeon Sturgeon are one of the oldest liv- broadcast their sperm and ing , with fossil records Natural History (which are 2 to 4 mm in diameter dating back more than 150 million depending on the species) during years. Their skeletons are mostly Most sturgeon are anadromous or spawning and the fertilized eggs cartilaginous. Distinguishing char- semi-anadromous; that is, they become very sticky so that they acteristics are a cylindrical shape; live in oceanic or brackish waters, adhere to rocks. The of five rows of large, bony plates respectively, and then migrate to females account for 15 to 25 per- called scutes; and heterocercal or freshwater rivers for spawning. cent of their body weight, and a top-elongated tail fins. Sturgeon Some, such as the lake and shov- female releases from tens of thou- are in the family Acipenseridae, elnose , are potamodro- sands to several million eggs per which includes about 26 species mous and live in freshwater their . in four genera—, , entire lives. and Sturgeon are long- . Eight lived. Atlantic, white species of sturgeon are found in and North America. There are five can live as long as 80 species of Acipenser: the white years and pallid (A. transmontanus) and can live for (A. medirostris) sturgeon on the more than 40 years. Pacific coast; the Because of their (A. oxyrinchus) and shortnose stur- longevity, female geon (A. brevirostrum) on the sturgeon are slow to Atlantic coast; and the lake stur- mature sexually. geon (A. fulvescens) distributed in They may not begin large rivers and lakes of the spawning until 20 Atlantic Ocean drainage and years of age and upper Mississippi River basin. usually spawn once There are also three species of every 2 to 5 years. Scaphirhynchus—the shovelnose Males will mature (S. platorynchus), pallid (S. albus) sexually a few years and Alabama (S. suttkusi) stur- sooner than females. Females usually 1Aquaculture Research Center, Kentucky have a brief repro- State University ductive period; they 2 Horn Point Laboratory, University of spawn when water Maryland 3 is deep and current Zoology Department, University of is strong enough to Oklahoma Figure 1. Life stages of the , Acipenser 4 prevent settling of Department of and Aquatic suspended matter, transmontanus. Sciences, University of Florida Fry hatch in 5 days at a water montanus), Siberian (A. baeri), ose- to 500 gallons (1100 to 1900 liters). temperature of 20 oC, 10 days at tra (A. gueldenstaedti), (A. Water is agitated to supply oxy- a temperature of 10 oC. Newly ruthenus), and a called gen and sodium chloride salt is hatched fry derive nourishment bester ( female x sterlet added at 0.25 to 0.50 percent (0.2 from their sacs for 5 to15 male). to 0.4 pounds per gallon; 25 to 50 days depending on water temper- g/L) to counter physiological ature. They begin external feeding Challenges for sturgeon stress. Approximately 2 pounds (1 when a “yolk plug” is excreted culture kg) of brood per gallon (4 from the (specialized liters) of water is a safe loading intestine). Fry first eat zooplank- There are several challenges to the rate for transport. When brood ton, and later worms, larger crus- production of sturgeon in the fish are removed from the hauling taceans and mollusks. They have United States. Supplies of brood- tank they should be placed on a extendible mouths (sucker-like) stock and fry are limited. There is stretcher (made of canvas or syn- surrounded by taste-sensitive bar- a long maturation period of at thetic tarp materials) that sup- bels and feed on or near the bot- least 8 years before females pro- ports the entire body so as to pre- tom. Their mobile jaws allow duce for . Sturgeon vent injury. Brood fish are first them to hold onto prey and spit require moderate temperatures of placed in maturation tanks until out sand and mud before ingest- 68 to 79 oF (20 to 26 oC) for ideal ready to spawn; then they are ing food. growth, and an ample supply of placed in spawning tanks. In well water is necessary. Facilities cooler climates, ponds can be used Current protection for sturgeon production are most- for long-term holding and matu- and as ly intensive, with expansive tank ration of brood fish. Ponds must systems, and require large be at least 6 feet deep and aerated an alternative amounts of operating capital. in the summer to keep water tem- For centuries, most sturgeon More markets for farm-raised perature cool enough and oxygen species have been highly valued sturgeon and their products need level high enough. for their roe or eggs, which are to be developed in the U. S. Brood fish are selected for spawn- processed into caviar. Sturgeon Although other sturgeon species ing by determining the stage of are also sought for their firm, have potential for culture, white gonadal maturity. Tissue samples boneless meat. Most sturgeon and sturgeon is currently the main from the gonads are obtained their products originate from the species being raised in the U. S. through a small incision in the , primarily from This publication provides basic abdomen; tissue forceps (e.g., Russia, Kazakhstan, Azerbaijan information about the propaga- Brown Adson and Allis forceps) and . The most popular tion, production, processing and or a stiff catheter may be used to species are the beluga (Huso huso), marketing of sturgeons, much of it remove the eggs (i.e., oocytes) or a the osetra or Russian/Persian based on the white sturgeon. piece of testicular tissue. The gen- sturgeon (A. gueldenstaedti / A. More detailed information can be eral appearance will differentiate persicus), and the sevruga stur- found in the references. males from females. from geon (A. stellatus). ripe males often can be collected There is a high demand for caviar. Propagation through the urogenital opening This, along with concern that behind the anus. Sturgeon have sturgeon is being altered, very dilute semen, unlike the creamy white liquid in most other caused sturgeon to be added in Brood fish were once obtained . The color, size and stage of 1998 to the Appendix II list of the from the wild. Now, however, maturity of the oocytes deter- United Nation’s Convention on brood fish of white sturgeon and a mines whether a female is ready International Trade of few Eurasian species (e.g., for spawning. Mature oocytes of Endangered Species of Wild Siberian) are being raised in most sturgeon species are dark Fauna and Flora (CITES). This hatcheries and capturing wild fish brown-black and 2.5 to 3.5 mm in CITES listing restricts the import is no longer necessary. This cer- diameter. Females that can be or export of sturgeon products tainly improves the potential for induced to release eggs will have into or out of the United States sturgeon culture because wild oocytes that are undergoing final unless a CITES permit is obtained sources are variable from year to maturation. Oocytes in advanced through the U.S. Fish and Wildlife year and because regulation by stages of maturity can be identi- Service. fisheries agencies can be problem- fied by the position of the atic. However, the 8 to 10 years Aquaculture of sturgeon can help nucleus, called the germinal vesi- required for many species of in the conservation of wild popu- cle (GV; see Fig. 2). Oocytes with sturgeon to reach sexual maturity lations through restocking and by the GV close to the edge, or near is both a significant operational providing a consistent supply the surface of the outer mem- challenge and an economic without exploiting wild popula- branes of the eggs, are the most liability. tions. The main species used in likely to ovulate (stages IV, V and aquaculture production world- Brood fish can be transported in VI). To view the nucleus or GV, wide are white sturgeon (A. trans- conventional hauling tanks of 300 oocytes are first boiled for 3 to 5 minutes and then cut in half An in vitro assay also can be used oocytes at GVBD is less than 90 lengthwise through the polar axis to estimate the readiness of percent, the female is not a good with a single-edged razor blade. females to spawn. Freshly collect- candidate at that time. Resample The polar area is located by the ed oocytes should be placed in a oocytes at 1- to 2-week intervals, presence of 10 to 12 funnel-shaped “maturation” solution (Ringer’s depending on the water tempera- holes (micropyles) in the egg solution with 5µg/ml proges- ture, to determine when the membrane. The position of the terone) and incubated at 74 oF female is ready. GV can be estimated either visual- (23 oC) for 16 hours. Movement ly (e.g., position I, II, III, etc. from of the GV (Germinal Vesicle Spawning conditions and the center to the side of the egg; Migration—GVM) during incuba- hormone injection Fig. 2) or by calculating the oocyte tion suggests readiness for polarization index or PI, which is induced maturation and pending Sturgeon can be propagated when the distance of the GV to the outer (Germinal Vesicle water temperature ranges from membrane divided by the oocyte Breakdown—GVBD). If more than 50 to 68 oF (10 to 20 oC). diameter (Fig. 3). Females selected 90 percent of the eggs are under- Spawning tanks for brood fish are for spawning should have a PI of going GVBD, the female is ready usually rectangular. Tanks should less than 0.07. to spawn. If the percentage of be large enough that fish can

AP A GV

B

VP AP = pole A = Distance between GV and cell VP = Vegetal pole membrane GV = Germinal vesicle B = Diameter of oocyte along animal-vegetal axis = Classification index A = B Fish that are good candidates to spawn in regular spawning Figure 2. Sturgeon oocyte stages (I-VI). season are in stage IV; Should be less than 1/14 or 0.07. Illustrations are of bisected oocytes showing the germinal vesicle (GV) positions. The stages show Figure 3. Diagram of a sturgeon oocyte showing the position of the the migration of the GV from the center of the germinal vesicle (GV) at the animal pole and the formula for deter- oocyte to the animal pole. Stage VI shows an ovu- mining the oocyte polarization index (PI) (modified from Detlaf et al., lated egg (modified from Shelton and Mims, 1981, and Conte et al., 1988). 1995). move a little but can’t turn. For Milt and egg collection of the eggs. The abdomen is cut example, a tank 7 feet long, 2 feet with a knife from the urogenitial To collect milt (sperm), handle the wide and 2 feet deep (2m x 0.6m x opening up to the anterior of the sturgeon with a restraining net 0.6m) would be suitable for stur- abdomen. A bowl is held directly but with the urogenital opening geon that are 50 to 100 pounds (23 under the initial cut to collect the exposed. Blot the urogential area to 45 kg). The height of the tank eggs. Additional bowls are filled dry and insert tygon tubing, com- should be convenient for handling until all of the eggs are removed. monly used for aquarium aeration the fish and for moving the fish in (3/16-inch or 0.5-cm diameter; 2 There are two other methods— and out of the tank with a stretch- inches or 5 cm long), attached to a caesarean section and the mini- er. Tanks should be covered with 20-cc plastic syringe into the mally invasive surgical technique shade cloth secured with rope to opening. Collect milt with gentle (MIST)—that do not require sacri- reduce lighting and prevent fish suction. With this method large ficing the female and are ideal for from jumping out of the tank. quantities (five to ten syringes) of maintaining brood fish for use in Optimal conditions for spawning milt can be removed from one subsequent years. Caesarean sec- are a water temperature of 55 to male each day for 3 to 4 days tion is a relatively quick surgical 63 oF (13 to 17 oC), a water without contamination by either method (30 minutes); a 4-inch exchange rate of five or more feces or water. Use milt from two (10-cm) incision is made in the times the volume of the tank or three males to fertilize eggs in abdomen, the eggs removed, and per hour, and water saturated order to increase genetic diversity. the incision sutured. The MIST with oxygen (100 percent; about Place a sample of milt in water method is more rapid (about 10 10 ppm at 62 oF or 10 mg/L at and view microscopically. If 75 to minutes). A small incision (0.5 17 oC). 100 percent of the sperm are inches or 1.5 cm) is made in the Ovulation and spermiation are motile the milt can be used. If less posterior-ventral area of the stimulated by injecting either than 75 percent of the sperm are just inside the urogenital fresh or dried common motile, use other males. Milt can opening (Fig. 4) using a scalpel (CCP) or sturgeon (SP) pituitaries, be collected several hours before with a no.11 straight blade. This or a synthetic Luteinizing needed and stored without aera- permits ovulated eggs to pass Hormone Releasing Hormone tion in sealed containers. from the body cavity through the analogue, LHRHa (e.g., des-Gly Refrigerate it (39 oF or 4 oC) or gonopore without going through 10, D-Ala 6- ethylamide). These cool it on wet ice (ice sprinkled the . With the Caesarean hormones are currently not with water). White sturgeon milt or MIST method only 50 to 90 per- approved for sturgeon; FDA has been stored up to 2 weeks and cent of the eggs can be removed. Investigational New Animal Drug used successfully when pure oxy- Regardless of the method used, (INAD) permits are required for gen is added to the milt in the the eggs must be collected free of their use. The injections are syringe and held at 39 oF or 4 oC. water and blood. Female sturgeon administered in the muscle Traditionally, between the lateral and dorsal females are scutes within the area extending sacrificed to from the base of the pectoral fin to collect the the midsection of the fish. Use a 1- eggs. Blows to to 3-cc disposable syringe with 23- the head or gauge needles. Females should severing the receive a total dose of either 1.8 spinal cord are mg per pound (4 mg/kg) of body common weight (BW) using CCP or SP, or a methods. To total dose of 0.045 mg per pound remove the (0.1mg/kg) of BW using LHRHa. eggs, the fish Administer a priming injection (10 is hung verti- percent of total dose) followed 12 cally on a hours later by a resolving injec- oviducts hook by the incision tion (90 percent of total dose). If mouth or gill responsive, females will ovulate opening so the within 18 to 30 hours after the sec- urogenitial ond injection when water temper- opening is at intestine atures range from 55 to 63 oF the waist level (13 to 17 oC). Males receive half of the person the total dose that females receive collecting the in one injection, usually when the eggs. The cau- females receive the priming dose. dal fin is cut Males should spermiate within and the fish is 18 to 24 hours at similar water Figure 4. The minimally invasive MIST procedure for removing bled to prevent temperatures. ovulated eggs from sturgeon (modified from Mims and Shelton, contamination In Press). weighing 50 to 100 pounds (23 to Nursery phase organic content. Deeper ponds in 45 kg) can release 250,000 to temperate climates may contain 500,000 eggs. Producing juvenile sturgeon is cooler water during summer. probably the most difficult part of Ideal water temperatures for Fertilization and hatching the hatchery process. Fry survival grow-out for many sturgeon depends on having a proper cul- species are 68 to 79 oF (20 to The eggs should be fertilized ture system and a complete nutri- 26 oC). Fish are raised for 3 to 4 using the “wet method.” Milt is tional program with attention to years for meat, 8 to 10 years for added to water (1 part milt to 100 diet formulation, feeding sched- meat and caviar. Sex of fish can- parts water) and then immediate- ule, food presentation and prefer- not be determined by tissue biop- ly poured onto the eggs [(0.3 ence. Fry are initially stocked at sy until at least 3.5 years of age. ounce (10 ml) of undiluted milt 60 to 80 per gallon of water (15 to per quart (liter) of water added to 20/L). Thereafter, the developing Because sturgeon forage on the a quart (liter) of eggs)]. There are fry should be stocked by weight bottom, stocking rates for juve- approximately 40,000 eggs per at not more than 0.4 to 0.6 ounce niles are based on surface area of quart or liter. The fertilized eggs per gallon (3 to 5 g/L). the tank bottom rather than total water volume. Stocking rates are become adhesive after a couple of Culturists of white sturgeon have minutes. The adhesiveness must 7 to 40 fish per square foot (75 to found it best to begin offering a 2 be removed if incubation is to be 430/m ) or 1 to 8 ounces per prepared diet a few days before square foot (300 to 2475 g/m2). in flow-through containers. The the yolk is completely absorbed. most common way to do this is to Rates vary depending on water This seems to familiarize the fry exchange rates and the degree of coat eggs with clay or Fuller’s with the odor of the feed and has earth. One minute after fertiliza- aeration. As fish grow some improved survival and growth. should be removed so there is tion, the clay suspension is Modified diets (#0-3 poured onto the fertilized eggs in ample foraging space. One fish crumbles) are used to feed fry 2 a proportion of 2 to 4 volumes of per square foot (11 fish/m ), with during the first 3 to 4 weeks. Feed minimal water exchange and dif- clay to 1 volume of eggs. The mix- is offered at a rate of 25 percent of ture can be stirred gently by hand fused aeration, to 2.5 fish per the total fish biomass every 24 2 so clumped eggs are separated. square foot (27 fish/m ), with hours, with feeding intervals of 2 greater water exchanges and oxy- The clay suspension should be to 3 hours. Automatic feeders pro- changed every 10 minutes to genation, are common stocking vide consistent presentation and rates for larger juveniles in meat maintain water temperature and uniform delivery over a 24-hour oxygen levels. The time and labor production systems where fish period. Young sturgeon have also biomass is about 1 pound per gal- required for de-adhesion depends been fed brine nauplii for on water temperature. At cooler lon (120 g/L). Stocking densities o o up to 30 days or until they grow for brood fish are lower and based temperatures (e.g., 55 F or 13 C) to about 1 to 1.3 inches (2.5 to 3.5 the process may take up to an on biomass. They can be as high o cm) long, before weaning them as 1 pound per gallon (120 g/L). hour; in warmer water (63 F or onto commercial starter diets. 17 oC) it may take about 30 min- Juveniles 1 to 5 inches long are fed utes. When the eggs are not Grow-out production 5 to 7 percent BW per day (2.5 to “sticky,” flush the bowl with fresh 12.5 cm); this decreases to 3 to 5 water until the water runs clear. There is little information on the percent for 6- to 12-inch fish (15 to The eggs are volumetrically mea- grow-out production of sturgeon 30 cm), and to 1 to 2 percent for sured (approximately 50 eggs/ml) in the scientific literature and fish larger than 1.5 pounds (680 g) and loaded into McDonald jars most information is proprietary. or 18 inches (48 cm). Continuous (2.6-gallon or 10-liter capacity) at The following information is feeding with belt feeders or simi- about 50,000 eggs per jar. Water based on some general practices lar devices is recommended. flow is adjusted to gently tumble for the market production of Research on sturgeon nutrition the eggs, which ensures oxygena- meat, caviar and broodstock. has been somewhat limited, but tion and reduces fungus develop- Grow-out of sturgeon is usually studies suggest that juveniles and ment. Dead eggs and clumps of done in circular tanks (6.5 to 9.5 brood fish should have a diet with eggs should be removed by yards or 6 to 8.5 m diameter x 1.1 at least 40 percent protein and 8 to siphoning. The optimal water to 1.7 yards or 1 to 1.5 m deep). 10 percent fat. Good growth has temperature for incubating eggs Tanks use either aerated, flow- been observed with salmonid of white sturgeon is 58 to 63 oF diets in which fishmeal is the o through well water or recirculat- (14 to 17 C). Fry will hatch in ing system technology. Raceways main protein source. Sturgeon are 7 to 9 days and begin to eat after are also used to a lesser extent. efficient converters of feed. Feed another 7 to 9 days. During this Juveniles don’t survive well in conversion ratios (FCR) of 1.0:1.4 time the mouth and foregut devel- pond culture, partly because of are common for juveniles and op, the residual yolk is absorbed, high water temperatures and 1.6:2.0 for adults. and the body becomes darkly ammonia levels at the soil/water Sturgeon have one of the fastest pigmented. interface of pond bottoms, espe- growth rates of all freshwater cially where soils have high fish—up to 11 grams per day for juvenile sturgeon under ideal As an anadromous species, stur- duction. Many sturgeon culture water temperatures. Averages of geon are adapted to varied water systems use supplemental oxygen 2.4 to 4.8 pounds per year (1.0 to quality in their natural habitat; sources and supply devices. 2.2 kg/year) are common with most sturgeon live in temperate Compressors or regenerative some species. In some studies fish areas with relatively mild water blowers can supply adequate oxy- grew to 6 pounds within 18 temperatures in summer (less gen if the biological oxygen months posthatch. To produce a than 80 oF or 27 oC). Spawning demand (BOD) of the culture sys- marketable size fish (1 to 3 kg for generally occurs in spring when tem is taken into account and the meat market) under optimal water temperature is 50 to 68 oF ample airflow is delivered. environmental conditions, stock- (10 to 20 oC) and optimal growth Sturgeon fry can be susceptible to ing density can exceed 60 to 70 occurs at 68 to 79 oF (20 to 26 oC). gas bubble disease when water is kg/m3 with oxygen concentration Water temperatures above 82 oF supersaturated with dissolved maintained at 5 mg/L. Survival (28 oC) slow or stop feeding and gases (more than 105 percent). rate is expected to be 50 to 80 per- growth. The Gulf of Mexico stur- Therefore, hatcheries should use cent from fry stage to marketable geon can survive summer water adequate degassing technology to size. Raising mature fish for temperatures of 86 to 90 oF (30 to drive off excess dissolved gases caviar production can be accom- 32 oC), but may lose weight and (see SRAC Fact Sheet 191 on plished in approximately 8 to 10 have more stress-related diseases. methods for degassing water). years. Sturgeon can also adapt to varia- Sturgeon fry and juveniles sur- tions in salinity. Ideal salinities for vive better in tanks than in ponds, Water quality early life stages are less than 1ppt; possibly because they feed on the Sturgeon have been cultured in adults can be cultured and trans- bottom where they are exposed to well and surface waters of varied ported in salinities of more than 3 higher concentrations of ammonia water quality. Some specific water ppt. Acclimating juveniles and and nitrite. Young sturgeon are quality requirements have been adults to salinities greater than 20 more sensitive to these parame- identified for a few sturgeon ppt should be gradually done ters than other pond-cultured species, largely based on the over 3 to 5 days. Salt baths have fishes. Like channel , stur- experience of hatchery and grow- been used to treat fungus and cer- geon can develop brown blood out facility managers. tain gill parasites, but fish may disease when exposed to high Generalizations can be made initially appear agitated and concentrations of nitrite. Adding about the quality parameters in should be watched closely during chloride ions can help, though the Table 1. Other parameters, includ- treatment. required chloride-to-nitrite ratios ing hydrogen sulfide, iron, heavy Like other culture species, stur- have not yet been established. metals and chemical residues, are geon can survive short periods Adequate biofiltration or water not clearly understood. Managers when the concentration of dis- exchange is required to maintain should have water tested and fol- solved oxygen is low (less than 3 concentrations of unionized low the guidelines that are mg/L), but prolonged exposure ammonia below 0.01 mg/L and known for other sturgeon species. causes feeding to slow and concentrations of nitrite below 0.1 As with most species, young stur- increases the risk of parasitic and mg/L. geon are more susceptible to bacterial infections. Oxygen con- minor deviations from ideal centrations of 5 mg/L or more are Diseases water quality than adults. recommended for intensive pro- Viral diseases have become a problem in intensive sturgeon cul- ture in the U. S. There is little Table 1. Recommended water quality concentrations for sturgeon information on the treatment of culture. these diseases. Four viruses have caused death in cultured white Parameter Recommended concentrations sturgeon: white sturgeon aden- Alkalinity 50-400 mg/L as CaCO3 ovirus (WSAV); white sturgeon iridovirus (WSIV); and two white Ammonia (unionized) < 0.01 mg/L as N sturgeon herpesviruses (WSHV-1 Dissolved oxygen > 5.0 mg/L and WSHV-2). At least one stress- Gas saturation < 105 % ful event (pump failure, handling, Hardness 50-400 mg/L as CaCO transport) occurred 9 to 32 days 3 before the appearance of the dis- pH 6.5-8.5 eases. Mortality often occurs over Nitrite < 0.1 mg/L as N a 4- to 5-month period with up to Salinity 0-0.5 ppt for fry; 0-3 ppt for juveniles; and 3 ppt 95 percent loss of juvenile white sturgeon. These viruses are for adults believed to come from the brood- Temperature varies with species; 50-68 oF (10-20 oC) for stock, which is known as vertical spawning, and 68-79 oF (20-26 oC) for grow-out transmission (i.e., gamete-associ- ated route) rather than from tank- Caviar help in restocking wild popula- to-tank transmission. No antiviral tions and in meeting consumer Caviar, or salted roe, is a nutri- immunization is currently avail- demand for products. Sturgeon tious . More than 90 per- able. Viral infection might be pre- have many positive culture attrib- cent of the caviar in the interna- vented or controlled on the farm utes including fast growth, good tional market comes from stur- by maintaining selective brood- feed conversion, ability to accept geon caught in the Caspian Sea, stock for reproduction, stocking crowding, and relatively good but the catch there is declining so fish that survived viral outbreaks, hardiness. Much of the necessary sturgeon are being cultured to harvesting all fish in a tank (“all- culture technology has been produce caviar. In 2000, approxi- in all-out” production) and developed. Challenges in sturgeon mately 4 tons of caviar were pro- decreasing stocking densities. A culture are the long maturation duced and sold from farm-raised PCR assay is being developed that period (5 to 10 years depending white sturgeon in the U.S. Whole- might detect infections in virus on species) and the limited avail- sale prices in the U.S. range from carriers and make it possible to ability of brood fish and seed. A $113 to $531 per pound ($250 to segregate virus-free broodstock consistent supply of juveniles $1170 per kg) depending on the and their offspring. needs to be developed in order to species. Bacterial infections rarely have expand production. Prospective To have high quality caviar, the been reported in intensive culture culturists should do a thorough fish must be sacrificed. After systems, but have been reported economic analysis of business bleeding the fish, the ovaries are in several species of sturgeon potential and be prepared to make removed and pushed through a obtained from wild populations. a significant capital investment. 1/8-inch (3-mm) screen to separate The most common bacterial infec- the eggs from tissue. There are tion was Aeromonas hydrophila. Suggested references two forms of processed caviar— Others included A. sobria, malossol and pressed. Malossol (a Britt, D. C., A. M. Lazur and P. Streptococcus sp., Edwardsiella tarda Russian word meaning “not much Zajicek. 1998. Market and Yersinia ruckeri. Bacteria are salt”) caviar is lightly salted and is Assessment for Florida sensitive to oxytetracycline at 5 cc the most common type. The salt Sturgeon. Florida Department per 10 gallons administered for 30 content ranges from 2.4 to 4.4 per- of Agriculture and Consumer minutes each day for 10 days. cent (other caviar may contain as Services, Division of Fungus of eggs (saprolegnia) can much as 11 percent salt). The Aquaculture. be controlled by removing dis- lower the salt content the better eased eggs or by using a saline Chebanov, M and R. Ballard. 2001. the caviar, but the shorter its shelf (NaCl) bath of 2.6 mg/L for 30 to The culture of sturgeons in life. Malossol should be refrigerat- 60 minutes. Russia: production of juveniles ed at 28 to 39 oF (-2 to 4 oC) and for stocking and meat for Processing and marketing has a shelf life of 3 months. human comsumption. Aquatic Today, most caviar is pasteurized, Living Resources 14:375-381. Meat which increases the shelf life to 12 to 15 months. Pressed caviar is Conte, F. S., S. I. Doroshov, P .B. Sturgeon meat is firm, white and made with a mixture of eggs, with Lutes and E. M. Strange. 1988. boneless, and has long been popu- some that may be overripe, Hatchery manual for the white lar in the U.S. In 2000, approxi- underripe, or from different sturgeon (Acipenser transmon- mately 600 tons (544 metric tons) species of sturgeon. The eggs are tanus Richardson), with appli- of farmed-raised white sturgeon heated slightly and pressed in a cation to other North American meat was processed and sold in cloth. Pressed caviar is used as a Acipenseridae. University of the U.S. It is presented in two spread on toasts or (small California, Division of forms—bullet (head, internal buckwheat pancakes). Caviar is Agriculture and Natural organs and fins removed) and fil- usually packed in tin boxes at the Resources, Cooperative let. The dress-out percentage for wholesale level and repackaged Extension, Oakland. white sturgeon is 70 percent in for retail sales in smaller tins or De Meulenaer, T. and C. bullet form and 40 percent in fillet jars ranging from 1 ounce to 2 Raymakers. 1996. Sturgeons of form. Prices range from $3.50 to pounds (30 g to 1 kg). the Caspian Sea and the inter- $5.00 per pound ($7.70 to $11.00 national trade in caviar. Traffic per kg) for bullet and $5.00 to Summary International, Cambridge, $6.00 per pound ($11.00 to $13.20 United Kingdom. Sturgeon products—caviar and per kg) for fillet. Hot- and cold- Detlaf, T. A., A. S. Ginzburg and smoked sturgeon meats are value- meat—are of high quality and value and have well-established O. I. Shmal’gauzen. 1981. added products popular with East Development of sturgeon: egg and West coast consumers; retail markets in the U.S. and world- wide. With over- and habi- maturation, fertilization, prices for it range from $18 to $24 embryonic and prelarval devel- per pound ($40 to $53 per kg). tat loss, wild sturgeon stocks are limited. Sturgeon aquaculture can opment (in Russia). Nauka Press, Moscow, U.S.S.R. Khodorevskaya, R. P., G. F. Logan, S. H., W. E. Johnson and Ronyai, A. and L. Varadi. 1995. Dovgopol, O. L. Zhuravleva S. I. Doroshov. 1995. Economics The sturgeons. pp. 95-108. In and A. D. Vlasenko. 1997. of joint production of sturgeon C. E. Nash and A. J. Novotny Present status of commercial (Acipenser transmontanus (eds.). Production of Aquatic stocks of sturgeons in the Richardson) and roe for caviar. . Elsevier, Amsterdam. Caspian Sea basin. Aquaculture 130:299-316. Wade, E. M. and J. F. Fadel. 1997. Environmental Biology of Fishes Mims, S. and W. Shelton. In Press. Optimization of caviar and 48:209-219. Culture. In: A. M. meat production for white stur- Logan, S. H. and K. Shigekawa. Kelly and J. Silverstein, (eds). geon (Acipenser transmonatus). 1986. Commercial production Manual of Fish Culture III. Fish Agricultural Systems 54: 1-21. of sturgeon: the economic Culture Section of the Williams, J. D. and G. H. dimensions of size and product American Fisheries Society, Clemmer. 1991. Scaphirhynchus mix. Giannini Research Report Bethesda, MD. suttkusi, a new sturgeon No. 335. Division of Plumb, J. A. 1999. Health mainte- (Pices:Acipenseridae) from the Agriculture and Natural nance and principal microbial Mobile Basin of Alabama and Resources, University of diseases of cultured fishes. Mississippi. Bulletin of the California, Davis. Iowa State University Press, Alabama Museum of Natural Ames, Iowa. History 10:17-31.

SRAC fact sheets are reviewed annually by the Publications, Videos and Computer Software Steering Committee. Fact sheets are revised as new knowledge becomes available. Fact sheets that have not been revised are considered to reflect the current state of knowledge.

The work reported in this publication was supported in part by the Southern Regional Aquaculture Center through Grant No. 00-38500-8992 from the United States Department of Agriculture, Cooperative State Research, Education, and Extension Service.