Called the “speckled trout” by most Southerners, the spotted sea trout is the most popular game fish on the coastal area of the northern Gulf of Mexico, but still little is known about it.
Jody Callihan, oceanography and coastal sciences graduate student, has been studying the fish’s migration habits since May on a large-scale project that is expected to last until the summer of 2009.
“Because we are only a quarter of the way through the study, we only have preliminary results, but what we have found so far is still interesting and helpful,” Callihan said. “I chose this particular fish because there is a serious lack of information about it, especially for something so common.”
Callihan is conducting the study at Calcasieu Lake near Lake Charles, where he tagged about 50 fish with acoustic transmitters and released them back into the water. There are various receivers, from Lake Charles to the shipping channel that leads to the Gulf of Mexico, placed along the floor. If a fish passes the receiver from a few hundred yards, the transmitter inside the fish sends a signal.
“The fish usually do well with the transmitters,” Callihan said. “We have only had a few who did not take to them well.”
The signal tells those in the program which fish were spotted, which direction they went from the transmitter and some of their health conditions. The Louisiana Department of Wildlife and Fisheries aids Callihan in his study. They provide transportation and service the equipment.
“We do a lot of work with LSU, and we assisted Jody in several of his studies, including this one,” said Mike Harbison, biologist manager for Coastal Area 7 of the Department of Wildlife and Fisheries. “When this study came up, we were really excited about it.”
James Cowan Jr., professor of oceanography and Callihan’s adviser for the study, wrote the proposal for the tagging project.
“Tagging and the information we can obtain from tagging are the main ideas here,” Cowan said. “Jody is a good student and big contributor to the project.”
The study aims to determine migration patterns, recognize habitat preferences and learn about behavior and movement as related to gender and size.
“There is little detailed scientific information on their movement patterns, and such information is vital for effective management of this recreationally and economically important species,” Callihan said.
Callihan said 20 percent of the fish have moved offshore and have not returned. The oceanographers are hoping they return in the winter or the spring because the transmitters only last for about a year.
“We have noticed several patterns, such as they tend to move to saltier areas of the water, but we still have a lot of work to do, especially with reefs,” Callihan said.
Another aspect of the project is reef-building. Spotted sea trout tend to use the abandoned colonies of oysters as homes. Callihan and his group are trying to find out if they will also use artificial reefs as a habitat.
“We want to see what types of habitats they tend to use to promote their survival, whether they are ones that we can build or not,” Callihan said.
Callihan said the fish were caught by volunteers at Hackberry Rod and Gun, a hunting and fishing store in Lake Charles and are a variety of sizes that accurately represent the fish population for this study.
“What Jody is doing is important. We are still in the middle of the study, but we are looking forward to the results,” Harbison said.
—-Contact Gina Zanutto at [email protected]