Sept/Oct 2016For Wildlife Watchers: Sturgeonby Rob Simbeck
Beauty, like success, is a matter of perspective, and sometimes the concepts intertwine. At the end of a boxing match, you don't have to be pretty; you just have to be standing. On an evolutionary scale, the single best measure of success and, arguably, of beauty, is longevity.
That makes the sturgeon, aesthetics aside, one of the world's more beautiful creatures. It has, after all, been slurping clams, snails, worms and crustaceans from ocean and river bottoms since 150 million years before the comet that wiped out the dinosaurs. It is a true marvel of adaptation that's tale of survival soured only in the last century or two, thanks, as you might expect, to Homo sapiens.
Built like a shark-catfish hybrid, the Atlantic sturgeon - one of twenty-seven sturgeon species worldwide - is noteworthy first of all for its size. A specimen that washed up on Folly Beach south of Charleston in March 2012 prompted "Sea Monster" headlines. The largest ever recorded was fourteen feet long and weighed eight hundred pounds. Its relative, the Eurasian beluga sturgeon, has reached twenty-four feet and more than 3,500 pounds.
The Atlantic sturgeon has a bony, ancient look, as though it were carved from stone. It is bluish-black or olive brown with paler sides and a white belly, with a dorsal fin sitting well back near its tail. Its skeleton, like that of sharks, is mostly cartilaginous.
This is a bottom feeder that uses its snout and four sensitive, catfish-like barbels to probe sand and mud. It sucks food into a soft, toothless mouth which extends like a camera lens, expels silt and gravel through its gills and grinds up its meals in a gizzard-like stomach.
The sturgeon was here in abundance when European settlers arrived. Some considered them a nuisance, since their rows of bony plates, called scutes, could tear up fishing nets. Eventually though, people warmed up to them. Their meat became a cheap, popular alternative to smoked salmon, their skin yielded leather used in clothing and bookbinding, and their swim bladders provided isinglass, a gelatinous substance used in clarifying glue and in making jelly, beer and wine.
And then there was caviar. The salted eggs of the sturgeon were considered a delicacy in Europe, and American fishermen were happy to serve those markets. By the late 1800s, we exported seven million pounds of sturgeon yearly. South Carolina's share was a quarter of a million pounds, with individuals averaging three hundred pounds. Gradually, overfishing, dams, dredging and pollution contributed to a steep decline, and by 1940 the average in the state was seventy-five pounds per fish and the harvest a mere ton-and-a-half. The business limped along until 1985, when the DNR ordered the state's commercial Atlantic sturgeon fishery closed. Regional and federal moratoriums followed, and the federal government placed it on the endangered species list in 2012 (worldwide, twenty-three of twenty-seven sturgeon species are endangered).
Part of the challenge is that sturgeon reproduce slowly. A long-lived fish (sixty years or so range-wide, with thirty years being a better estimate in South Carolina, according to Bill Post, diadromous fishes coordinator with the DNR), the sturgeon is slow to begin spawning.
"Southeast Atlantic sturgeon males can reach sexual maturity at age seven," says Post, "but it is more likely eight to twelve, and for females twelve to fifteen. Typically, males are thought to spawn every one to three years, although there have been numerous accounts that suggest males frequently spawn annually."
They were long thought to be only spring spawners, but, adds Post, "we have some rivers where both spring and fall spawns are observed. For instance, in the Edisto River, we've discovered the fall and spring fish are genetically distinct from each other." There are also spawning records in the Pee Dee, Combahee, Savannah and Waccamaw rivers.
What they lack in frequency, they make up for in volume.
"Fecundity has been correlated with age and body size," says Post, "so it can be highly variable, but generally 500,000 to 1.5 million eggs is a safe estimate. Recently a tugboat strike in Delaware killed a gravid female, and the folks there pulled out 53 pounds of roe, an entire five-gallon bucket full."
Atlantic Sturgeon - Acipenser oxyrinchus
Description: Bluish-black to green, lighter sides, white belly, snout with barbels. Five rows of bony scutes, rather than scales.
Habitat and Range: River bottoms when young and while spawning. Otherwise, ocean-dwellers.
Reproduction: Late maturity. Spawns spring or fall. Female lays hundreds of thousands to millions of eggs.
Viewing Tips: Rarely sighted. This is one species that is best read about or viewed on video.
Following spawning, adults swim in a matter of days back to estuarine waters, according to transmitter data.
They don't seem to have much to worry about apart from us.
"Sturgeon are not thought to have natural predators, and no specific diseases are associated with any observed mortalities," says Post. "Any parasites are thought to be external nuisances and are not thought to cause harm."
Traditional rod-and-reel fishing has never been a threat on the Eastern seaboard, as "no records of hook-and-line Atlantic sturgeon captures exist in the Southeast," according to Post. "They simply don't seem to be interested in bait or they are not present in large numbers where fishing occurs."
There are plenty of other concerns. They are a bycatch in some commercial fishing methods, and are susceptible to ship strikes and affected by water quality, dredging and dams.
Because of the Endangered Species Act listing, "actions such as stocking are almost impossible," says Post. Still, despite range-wide concern about the species' future, the signals are mixed in the state.
While even determined wildlife watchers seldom come across these animals, those rare encounters hold definite hazards. Sturgeon leap from the water on occasion, for reasons not yet understood.
As for caviar, worldwide most is a product of aquaculture, including an operation in North Carolina. We can only hope that changes in tastes, markets and our relationship to wild places can spell a brighter future for this otherwise beautifully adapted living fossil.