By Timothy Fitzgerald, Environmental Defense fisheries scientist

Long the provender of imperial banquets and champagne tastes, beluga sturgeon caviar from the Caspian Sea has been called the Rolls Royce of caviar. But therein lies the problem. Likened to black gold and magic pearls, the eggs of the beluga sturgeon are so prized that this bony ancient fish, going back 200 million years to the age of dinosaurs, has been fished to near extinction in the Caspian Sea.

Although the eggs from beluga are considered the crème de la crème of caviars, the other wild sturgeon species inhabiting the Caspian and Black Seas are also highly sought after and similarly depleted: Russian sturgeon (the caviar is known as osetra) and Stellate (sevruga caviar). Enormous international demand for caviar has significantly depleted most wild sturgeon populations worldwide.

The United States banned the import of beluga caviar after listing the species under the U.S. Endangered Species Act in 2005. It also prohibits imports of sevruga and osetra. Any of these types of wild caviar sold in this country will be illegal or past their shelf life and thus risky to eat.

Farmed roe wins praise from chefs as a substitute for wild depleted species

But for those who crave this delicacy, farmed white sturgeon caviar or closely related paddlefish caviar is a delicious eco-friendly alternative and increasingly praised by chefs."Loyal consumers of osetra, sevruga or beluga caviar form the Caspian Sea may find, as one New York Times reporter has, that caviar from farm-raised white sturgeon rivals the best Russian osetra," note the authors in "One fish, Two Fish, Crawfish, Bluefish: the Smithsonian Sustainable Seafood Cookbook."

Farmed sturgeon eggs range in color from cream and gray, olive and gold, to black (the various colors represent different grades) and, like their wild cousins, are traditionally served with toast points, spooned atop blinis or eggs, or garnishing raw oysters. Not only is farmed caviar less expensive than its wild counterpart, consumers can rest assured that farming operations are relatively benign – they do not significantly pollute local waters or destroy critical habitat. Other ecologically sound choices are roe from wild salmon and rainbow trout.

Postscript: Problems remain for wild sturgeon caviar in the international arena

Is there hope for dwindling wild sturgeon populations in Eurasia? Unfortunately and inexplicably, earlier this month the Convention on International Trade in Endangered Species (CITES) reopened limited trade in wild beluga caviar, after shutting down trade last year because of concerns about overfishing, illegal poaching and ineffective management. Beluga in the wild has declined by 90 percent in the last 20 years, according to the conservation group Caviar Emptor.

The lifting of the CITES ban on exports makes no sense from a scientific or biological standpoint. Beluga sturgeon are slow-growing, late-maturing fish that can live up to 100 years and weigh more than 1,500 pounds, making them particularly susceptible to fishing pressure. The ban was in effect for only one year, hardly enough time for the species to rebound or show signs of recovery. That would take years of careful management and science-based limits on catches or a reprieve from fishing altogether.

In the meantime, Environmental Defense urges consumers to choose responsibly farmed caviar produced in the United States and Europe.

Editor's Note: We're happy to introduce another blog feature today, a bi-weekly column by Environmental Defense. Every two weeks, Online Activism & Outreach Coordinator Jessica Bosanko will bring you news, information and action items about ED's efforts to "find innovative, practical ways to solve the most urgent environmental problems."

By Timothy Fitzgerald, Environmental Defense scientist

Seafood lovers who want safe and eco-friendly fish might need help sorting through the mixed messages out there. The issue is complex – but here's how to sort through it why to choose healthy, sustainably caught or farmed fish.

Eating even modest amounts of fish helps protect against heart disease and is essential to the developing brains of fetuses and young children. The federal government and the American Heart Association both recommend two servings of seafood a week to reduce the risk of heart disease and death from heart attacks. The greatest cardiovascular benefits come from eating fish high in long chain omega-3 fatty acids, such as small oily species like herring, and mackerel, and larger predatory fish like salmon and some tuna.

Fish are disappearing from the oceans

Sadly, even as the health benefits of eating fish are becoming clearer, the ocean's ability to provide plentiful seafood is diminishing.

Since the 1950s, when industrial fishing began in earnest, large fish have mostly disappeared from the oceans, plummeting by an astonishing 90 percent according to a 2003 analysis. If we continue current fishing practices, most fisheries will be exhausted by mid-century, a recent report concluded. Many of America's favorite seafood – Atlantic cod, sea scallops, flounder, grouper, snapper and more – are already overfished.

At the same time, health-conscious consumers worry about fish with toxins such as mercury, dioxins or PCBs. To avoid too much mercury, children and women of child-bearing age should be careful about how much large fish they eat, such as swordfish and shark. Some farmed Atlantic salmon is also high in cancer-causing toxins like dioxins and PCBs.

(More on the health benefits of eating fish and sustainable fisheries [PDF])

So how can these complex tips be simpler?

Environmental Defense's Seafood Selector provides a list of best and worst choices for the ocean. It highlights fish that are heart-healthy (high in omega-3s) and those that are either high or low in contaminants. It includes advice on how many times it is safe to eat a particular fish each month.

Stay tuned for upcoming posts where I'll focus on the environmental and health aspects of specific seafood choices.