Sturgeon reproductive physiology research in the laboratory of Dr. Serge Doroshov and Mr. Joel Van Eenennaam, at the University of California, Davis.
1. Reproductive Biology of Green Sturgeon.
The green sturgeon (Acipenser medirostris) is an anadromous fish that occurs along the western coast of North America. While green sturgeon has a lower value in commercial and sport fisheries of the Pacific Coast, compared to white sturgeon (Acipenser transmontanus) it is a highly valuable species in traditional tribal fisheries and in the biodiversity of the Pacific Northwest’s ecosystems. Even though the National Oceanic & Atmospheric Administration (NOAA) Fisheries proposed listing the southern population as threatened, under the USA’s Endangered Species Act, there is a scarcity of information about its life history. Because green sturgeon life history information is critical to this species’ protection, a multidisciplinary project was initiated in 1999 to elucidate the general biology of green sturgeon, conducting studies of the species: 1) movements and distributions, 2) physiology, 3) reproductive biology, and 4) genetics.
Our laboratory has been conducting studies in three areas to, 1) increase reliability and efficiency of artificial spawning, egg fertilization and embryo incubation, 2) characterize gametogenesis and the gonadal cycle, and 3) describe the reproductive characteristics of the green sturgeon.
2. Farmed Caviar Production in the Western United States (a brief overview).
The Western United States aquaculture industry continues to make significant progress in domestication and culture of white sturgeon, primarily in California and Idaho. The most note-worthy aspect is the sustained production of caviar during the past few years.
The inter-disciplinary Western Regional Aquaculture Consortium ( WRAC) Sturgeon Broodstock Development Projects (1993-2003) conducted in direct collaboration with industry were highly successful in improving the management of sturgeon broodstocks. Sturgeon farms have achieved independence from wild broodstock and use effective methods to produce their own seed stock each year. Most recently, the Idaho sturgeon industry has had several years of highly successful spawning of the indigenous sturgeon stock and is fully capable of producing endemic seed stock to fill the needs of their states commercial industry.
Broodstock maturation rates and reproductive performance were improved by optimization of thermal and feeding regimes, development of reproductive diagnostic assays, and improved hormonal spawning induction procedures. Management recommendations from the epidemiologic studies have been directly applied by sturgeon growers and survival of juveniles has improved. F arms now routinely make decisions on risk factors contributing to viral outbreaks during production, and the bottom line is that viruses are not affecting meat and caviar production levels, at this time.
There are currently three major sturgeon farms in California and four in Idaho that have successfully spawned sturgeon. There are also a couple smaller growers that focus on meat production, after obtaining hatched larvae from another farm. As a direct result from this project’s research and outreach, and our long-term collaboration with our colleagues at Malaspina-University College, there is also one recently established commercial white sturgeon farm in Canada.
The western region sturgeon industry is now able to replace products from the severely depleted worldwide commercial fishery with sustained production of meat and caviar. The estimated annual production levels has been about 1,000 MT of food fish and 5-7 MT of caviar, during the past few years. Approximately 2000 individual females have been processed annually for caviar, and the average yield per fish was about 3 kg of final product (canned caviar).
The rapid decline in caviar supplies from wild populations and the increasing harvest restrictions, particularly in the Caspian Sea region, will undoubtedly continue to create a demand for other sources of caviar. Given that the U.S. has historically imported over 50 tons of caviar each year, and the fact that there are restrictions on international trade of sturgeon caviar (CITES permit requirements), the U.S. sturgeon industry will almost certainly be a major source of caviar in the future. However, the continued expansion and sustainability of sturgeon farming for caviar (and meat) will ultimately depend on culture regulations, production costs, long-term demand, and price.
Although this project has been successfully completed, there are continuing and future research directions for white sturgeon aquaculture. These include: alternative sex identification techniques, breeding plans for selection of desirable traits, monosex production, post-harvest technology (i.e., for caviar), disease detection and control, and development of optimal feeds for growout, broodstock and caviar production.
Contact for above projects:
Joel Van Eenennaam
University of California
Department of Animal Science
One Shields Ave. , Meyer Hall
Davis , California 95616 USA
Tel (530) 752-2058
Fax (530) 752-0175
Email: jpvaneenennaam@ucdavis.edu
Next page > Outline of current research projects by the Sturgeon Research Group (SRG) / Danube Delta National Institute (DDNI), Tulcea (Romania)
