Lake Pontchartrain is low on saltwater, and low on speckled trout

An abnormally high river has left Lake Pontchartrain low on saltwater and devoid of speckled trout this summer. The river height has been dropping, but it’s almost impossible to predict when the lake will return to normal, according to environmental scientist Dwight Bradshaw.

“The river is still pretty high, higher than normal, but is starting to drop pretty fast. And that’s important to get to a normal salinity regime,” he said.

Even though the river has been dropping at a considerable rate we could see extremely low salinity levels persist for the months ahead unless very specific weather events occur.

“If a Bermuda high comes in with a strong south-southwest wind, it will have a powerful effect (on salinity levels). A tropical system could do that too. But that’s not something that anybody really wants,” Bradshaw said.

Currently the lake is at an average salinity level of 0.4 ppt (parts-per-thousand). A normal salt solution would be 10 ppt, according to Bradshaw. These conditions are still favorable for an algae bloom and are something that the Department of Environmental Quality is closely monitoring.

“We have to watch the algae bloom; we’ve seen very limited amounts of blue-green algae, which causes real problems with toxicity when they die.”

Blue-green algae can be seen in this image from March. (Photo courtesy Rob Perillo)
Blue-green algae can be seen in this image from March. (Photo courtesy Rob Perillo)
This is a current satellite image of Lake Pontchartrain.
This is a current satellite image of Lake Pontchartrain.

Hope for fisheries

Shrimpers have had a lackluster brown shrimp season east of Pontchartrain in Lake Borgne but this has been balanced by the white shrimp catch.

“The shrimpers are doing well with white shrimp in Borgne. The white shrimp season may actually be better than average,” Bradshaw stated.

Bradshaw went on to say that the blue crab population will likely come back stronger than before and that this is normal after these kinds of events and even though conditions are not favorable for speckled trout in the lake, trout have been returning to Hopedale and the Biloxi Marsh.

Those concerned with the salinity levels in the lake can find a good resource at https://saveourlake.org/lpbf-programs/water-quality/weekly-data-report/