Spillway continued
ity testing throughout the lake and coupled the data with the
movement of 211 speckled trout tagged by LSU PhD student
Ashley Melancon. Bramer’s analysis showed that one particular
habitat was not preferred over another, however, she was able
to determine it was the diversity of the habitats that was important. She also found that salinity is the strongest influence on
speckled trout movements in the lake, followed by temperature. These study results are interesting and may confirm or
cancel out a few of those theories out there.
On January 10th, sixty percent of the Bonnet Carré Spillway’s gates were opened for 22 days. This is the most recent
event-driven influence on Lake Pontchartrain, and during the
opening, a generous amount of sediment-loaded Mississippi
River water was relocated into the Lake. During the opening,
several tagged fish were present in the Lake – 26 speckled trout
and 23 redfish. One week after opening, tagged speckled trout
and redfish located in the southeast portion of the Lake began
to move toward the Lincoln Beach area, and then headed
north. Two weeks after opening, over 90 percent of all tagged
redfish and 100 percent of speckled trout were in the northeastern portion of the Lake, most located at the St. Tammany East
Reef, also known as the Lacombe Reef. One week after the
spillway closed, the speckled trout and redfish began to disperse to the middle of the Lake again. One redfish was detected leaving through the Rigolets and one speckled trout
through Chef Pass, but both fish returned before February 18th,
the cutoff for our detection data. Fish movements were overlaid
with MODIS satellite images, and trout and redfish can be observed moving into pockets of cleaner water, although salinities
in these areas were at or below two parts-per-thousand.
There are many variables that make this Spillway opening a
unique one. Since the structure’s completion in 1931, this was
only the second time it was opened during the winter, and was
open only nine days longer than the shortest recorded duration. Speckled trout and redfish are resilient and able to conform to Lake Pontchartrain’s impermanent conditions. They
have remained in the Lake for now, navigating th H