Dan Burden, International and Special Projects, Extension Value-added Agriculture and AgMRC, Iowa State University,
Revised June 2012.
Sturgeon are ancient, cartilaginous skeleton fish from a fish family more than 60 million years old. The majority of them are anadromous; a certain portion of their life is spent at sea or in large bodies of fresh water from which they run up freshwater streams to spawn. They tend to be bottom feeders, consuming insect larvae, small fish and occasionally fish-related carrion. In rivers that support salmon populations, sturgeon will forage on roe, as well as the decaying salmon remains from the deceased breeders.
Though legally protected since 1921, sturgeon has never really recovered from its past exploitation, due primarily to its long reproductive cycle. A female sturgeon cannot reproduce until it has reached 20 years in age. Even then they spawn every four to six years, or just three or four times during a 40-year average life span. In addition, the growth rate of all species is extremely slow. After an initial growth spurt, growth may only average between 1 to 1.5 inches per year. In large river systems such as the Fraser River in southern British Columbia and Oregon’s Columbia River, however, fish in excess of 180 inches and weighing more than 1,500 pounds have been recovered.
In the 1800s, sturgeon often became entangled in commercial fishing nets, and the fish were discarded as a worthless nuisance. Today, the sturgeon is recognized as one of the world’s most important commercial fish, prized for its caviar, or roe (eggs); meat and oil.
Eight species of sturgeon are native to North America, including the Pacific, or white, sturgeon (Acipenser transmontanus); the lake, or rock, sturgeon (Acipenser fulvescens); the shovel-nose sturgeon; and the endangered pallid sturgeon. There are numerous landlocked fresh-water sturgeon populations.
The white sturgeon, which may live for over 100 years, is the largest North American game fish. A white sturgeon from the Fraser River, weighing 149 pounds and 90 inches in length, was reliably aged at 71 years.
The lake sturgeon commonly reaches 36 to 72 inches and weighs from 10 to 80 pounds. This fish of the Great Lakes region is a huge, heavy, bony-plated fish with a sharklike tail that lives in large rivers and lakes, and once was found throughout the Mississippi River, the Great Lakes and the Hudson River. In the Wisconsin Lake Winnebago Wolf River system, a 79-inch, 188-pound lake sturgeon was harvested during the February 2004 spearing season that established a new sport-fishing record for the state.
Almost all species are completely protected from commercial or sport fishing. Where sport fishing is allowed, it is closely managed and regulated. To prevent poaching, most sturgeon spawning sites are actively patrolled by game management and law enforcement agencies. Illegal demand for female sturgeon drives poaching, even though most poached fish are unsuitable for “ripe” roe recovery. For instance, lake sturgeon do not spawn until they are 20 to 25 years of age and then have ripe roe only about every three or five years thereafter.
Until 1966 in the United States, caviar could originate from the salted roe of several species of sturgeon and any fish roe that could be colored black was called caviar. In 1966, the U. S. Food and Drug Administration defined caviar as only the eggs of the sturgeon, with salmon roe being referred to as “salmon caviar.”
In most states that have a sport harvest, the sale of roe is illegal to assist in combating the illegal trade in other roe from other protected populations. However, in some states where it is legal to take a sturgeon for sport or commercial purposes on hook and line or by net, current demand for caviar eggs for commercial or black-market sale may endanger some species. This is the case in a few states where legal fishing for the shovel-nose sturgeon may threaten the endangered pallid sturgeon. Along the Missouri and Mississippi rivers, commercial fishermen (anyone paying a $25 license fee) can now legally “broker” in sturgeon eggs.
In 2006, the United Nations agency that oversees trade in endangered species refused to issue export quotas for wild caviar from sturgeon in the Caspian and Black Seas, except for a small amount of Iranian caviar, effectively limiting international trade in wild caviar.
The astronomical price of wild caviar, the long maturation and reproductive cycle of the fish, and continuing depletion of natural stocks due to overfishing and habitat destruction is driving interest in using aquaculture to rear sturgeon for their egg production. Aquaculture of sturgeon (and the closely related paddlefish) for roe is rapidly developing as an industry in the the United States. Aquaculture-produced roe can be processed, packaged and legally certified on-site. The roe is environmentally sound and consumers receive a product that is guaranteed to be what is on the label.
Within the past 20 years, American production has gone from 5,000 pounds to over 75,000 pounds. Today, American caviar usually is as good as imported Russian and Iranian caviar and sells for $25 to $39 per 2-ounce jar (Gourmet Food Blog), a bargain compared to $55 to up to $270 per ounce for Caspian Sea Russian Beluga.
California growers produced 12,000 pounds of sturgeon roe in 2001 and about 32,000 pounds in 2006. Sterling Caviar, which operates the largest caviar farm in the United States near Sacramento, annually produces about 14,000 pounds. For the first time since it began producing caviar in 1994, Sterling conducted a second harvest in fall 2006 to meet demand. Traditionally, Sterling removed roe only in the spring, when the white sturgeon in the nearby Sacramento River naturally spawned. Tsar Nicoulai Caviar, an operation whose business office is located in San Francisco, shipped 5,000 pounds of aquaculture-produced caviar in 2001 and predicts sales of 25,000 pounds by 2008. (Caviar from farms instead of the seas 2006.)
Current production systems use fingerlings that are trained to eat a commercial diet. At three years of age, the sexes of the fish can be determined and the females are segregated. In five to seven years, the fish mature and may begin to develop the mature eggs. These “gravid” fish produce the roe (eggs) so highly prized for commercial caviar. Roe sacs are removed from the fish and screened to separate individual eggs. After a quick cleaning in fresh cold water, the roe is weighed and a proportional salt mixture is then added to it. The salting is done with a dry salt and mixed in by hand. At this stage, the product is first called caviar. After salting, the caviar is spread out on a fine screen to allow for a little drainage, a final check for impurities and assigned a market-standard grade. The caviar is then packed into tins for cold storage (26°-30°F) with a shelf-life expectancy of over one year (Sterling Caviar).
From its beginning in the mid-1990s, the farmed caviar industry has evolved into a global, multimillion- dollar business. Sturgeon farms in France, Germany, Italy and Uruguay are investing millions of dollars to expand facilities and to develop new technologies. For instance, at Agroittica Lombarda in Calvisano, Italy, the world's largest caviar farm, each female sturgeon has a microchip containing its genetic information, pond of origin and diet implanted in the back of its head. In Bulgaria, Canada, China, Israel and Abu Dhabi, caviar farmers are building new production facilities. (Caviar from farms instead of the seas 2006.)
In the United States, 10 farms raised foodsize sturgeons, two farms raised fingerling and fry sturgeons, and one farm raised stocker sturgeon. The two states most involved in sturgeon production were California and Idaho. (Census of Aquaculture 2005.)
Currently the meat from sturgeon is sold at gourmet food markets. The value of U.S. sturgeon exports plummeted from $63,000 in 2001 to $5,000 in 2005 but is slowly recovering. In 2011, the United States exported 97.7 metric tons of sturgeon valued at $741,000. Russia purchased more than 80 percent of the U.S. sturgeon exports.
Caviar from farms instead of the seas, Jane Black, International Herald Tribune, 2006.
Census of Aquaculture, 2007, USDA.
Global Agricultural Trade System, Foreign Agricultural Service, USDA.