When Álvar Núñez Cabeza de Vaca floated into Mississippi Sound with 240 of his Spanish compatriots in 1528, he and his men were dying of thirst. They’d been traveling by raft along the coasts of Florida, Alabama and Mississippi, and were so desperate for fresh water that they began drinking the water of the Mississippi Sound. A number of those who drank from the sound subsequently died due to the water’s high salinity. They were drinking seawater.
If Cabeza de Vaca were to float through the sound today, though, he and his men could drink freely of the sound’s water without worrying about ingesting too much salt. On May 17, 2019, the salinity of Mississippi Sound reached 1 part per thousand — low enough that it is considered freshwater by some measures. The normal salinity of seawater is around 35 parts per thousand, by contrast.
The drastically lowered levels of salinity in the sound can be attributed to the opening of the Bonnet Carre spillway on the Mississippi River. Water from the swollen Mississippi pours into Lake Pontchartrain via the spillway, and is then pushed in Mississippi Sound. Although the sound seems to the casual observer to be its normal self (other than an unusually brown tinge), the influx of freshwater has actually damaged the sound’s ecosystem. Dozens of turtles and dolphins have died, and Mississippi’s oyster industry has been hammered.
Officials make the infrequent decision to open the Bonnet Carre spillway when they fear flooding in New Orleans. But many people don’t realize the impact the spillway’s opening has on the Mississippi Gulf Coast.
Ryan Bradley, an oysterman from Pass Christian, Miss., wrote in February about the true and largely unknown impact environmental degradation (including changes in salinity) has played on Mississippi’s oyster industry. The numbers are shocking: in the mid 2000s, oystermen were harvesting 500,000 sacks of oysters from Mississippi waters. Now the number is 3,500. Mississippi’s oyster industry has collapsed.
The Foreman Family spent last Christmas in Bay St. Louis, Miss., and for Christmas dinner everyone wanted oysters. We visited the waterfront wholesaler in Pass Christian and bought several dozen. It wasn’t until we arrived back home that we noticed all the oysters had been harvested in Texas. We couldn’t get our hands on Mississippi-grown oysters, because there no longer were any.