While temperatures have warmed up after a recent spell of icy weather, this weekend is projected to yield more temperatures that will inspire bundling up.
For local fishermen, that isn’t inconsequential. When low temperatures and icy weather manifest, it can affect the behavior and survival rate of fish, and with it the degree of difficulty for the outdoorsmen attempting to catch them at the area’s popular fishing spots.
“Their metabolism slows down and the fish aren’t as excited,” said Luling outdoorsman Bruce McDonald. “They don’t have to feed as much. It makes it tougher to catch them, real hard in fact.”
The Louisiana Department of Wildlife and Fisheries also recently issued a warning that freezing water temperatures could result in fished killed throughout coastal Louisiana.
Jason Adriance, biologist for the LDWF, said that when the weather gets cold, fish in saltwater areas will school up and move to deeper channels, and will also become more sluggish.
“They’re going to, essentially, become less aggressive,” Adriance said. “They’ll go into slow ambush mode instead of being an aggressive predator. So your bait presentation would have to be a little slower.
“Typically water temperatures below 40 degrees Fahrenheit for any more than a day begin to cause problems for spotted seatrout, whereas red drum are slightly more tolerant and will begin to experience problems in the mid-30s. The rate at which the water cools is also important. If fish have a chance to acclimate and move, the potential for survival is better.”
Once the weather warms up, Adriance said, the fish tend to resume their normal pattern. But he added that in the months following a cold snap, one might see more instances of fish developing external parasites or secondary infections.
“You might see some fish with ulcers or parasites because of the stress they underwent (in the cold),” Adriance said.
Sean Kinney, inland fisheries biologist manager for the LDWF, notes that fish in freshwater bodies don’t share the same difficult adjustment to the shift in temperature as they tend to be more acclimated to colder weather.
“They love to change their depth, which is not always possible for saltwater species,” Kinney said. “Freshwater species usually have some thermal refuge they can go to that’s deeper in the water. They’re more tolerant of colder weather.”
That necessitates fishermen to target freshwater fish at deeper depths in winter. Where the weather could start affecting those species’ behavior and mortality rate comes in when those deep refuge areas aren’t available.
“It depends on where you are and what the maximum depth is,” he said. “If (freshwater species) are in the marsh, where they lack safe refuge, the deepest water may be no more than 10-12 feet.”
McDonald notes many pro fishermen travel to smaller basins and slow their presentations down, and that the length of a cold front can affects how long it can take for things to get back to normal.
“If it’s just a one or three day front, they come back a lot quicker. It just depends on the duration of the cold,” McDonald said.
He said the best bet to catch fish in a cold spell tends to be in shallow areas and in intersections with canals and salt water where the water is deeper.
“Out here, especially in South Louisiana, water gets blown out, so you have to fish the mouths of canals and lakes. Places that will absorb heat quicker,” McDonald said. “A lot of people switch from artificial to live bait.”
The LDWF said that more definitive estimates of the effects of the freeze on fish population sizes and distribution within the coastal areas will be available as information is collected through the department’s fishery-independent monitoring programs.