The drought and subsequent return of water to Lake Lanier may have made for fatter fish this summer and a larger population of fish next year, said Nick Jamison, a fisheries biologist for the state’s Department of Natural Resources.
Jamison and other fisheries biologists with the DNR’s Wildlife Resources Division regularly collect fish from the lake and record their weight and overall health, he said.
This spring, Jamison said he found that the fish of Lake Lanier were in better condition and had fatter bellies as a result of the drought. He said the drought reduced the surface area of the lake and made Lake Lanier one big, easy-access buffet for fish such as striped bass.
"It’s like pulling the cork on the bathtub," he said. "It was a lot less area for them to search."
And the long-term effect of the drought could be more fish in the lake next summer, he said.
When water receded from Lake Lanier’s shorelines, vegetation grew for nearly three spring seasons in its place. Now that those shorelines are under water again, the grassy waters provide a perfect nursery for young fish like bluegill, crappie and largemouth bass to mature without the threat of predators, Jamison said.
"Maybe next year we would expect some of our bluegill and perhaps largemouth bass numbers to go up, because they’ve got all this newly flooded vegetation to go into when they’re spawning," Jamison said. "The newly flooded areas ... allow them to hide from predators. Another, larger bass couldn’t get through there."
The drought has not been bad for the fish, Jamison said. In fact, the only time water levels can affect fish negatively is if the levels are too high, Jamison said. If the water reaches flood stage, it can reduce the area in which the oxygen and the temperatures are at a level that is just right for striped bass to survive. Larger fish usually die in a flood year, he said.
"A lot of folks just assume that low water, that’s bad for the fish, but not necessarily," Jamison said.
Whether the effect of rising lake levels on water quality is positive or negative varies from lake to lake, said Chip Cutcliff, an environmental specialist with Georgia’s Environmental Protection Division watershed planning and monitoring program.
When water levels increase, it can usually have an effect on water clarity. Bev Nichols said it is the only change she has noticed since rain returned to the lake’s basin.
Nichols is a board member for the Lake Lanier Association, a volunteer group focused on protecting the water levels and quality of Lake Lanier. She manages the results of about 25 water quality samples the group takes at different points on the lake each month.
Nichols said she has not noticed any other changes in the group’s test results that have been consistently related to fluctuating water levels over the years.
Recent samples of the lake have not shown much change in chlorophyll levels — in fact, Nichols said chlorophyll levels were relatively low — or water temperature in the lake, Nichols said.
The data does show, however, that the volunteers’ secchi readings, a measure of the water’s visibility in meters, have been lower lately, Nichols said.
Lower secchi readings could be a result of the recent dredging that many property owners around the lake have done around its perimeter while water levels have been low as well as the rainfall stirring up loose dirt on the lake’s shoreline, Nichols said.
But because Lake Lanier has a fairly stable shoreline and a big surface area, the rains have not had a big impact on visibility, Cutcliff said.
Even Nichols, who has noticed changes in visibility, said recent secchi readings have still shown that the lake has about five meters of visibility.
"Lanier seems to have stayed very, very clear," Cutcliff said.
If the health of the lake changes in light of recent rains, Cutcliff said the EPD will know. The division returns to the lake every month to monitor its health.
Cutcliff, who has worked on lakes around the state for 18 years and most recently on Lake Lanier, said water quality tests have all returned positive results this year. But those tests never showed anything negative during the drought, either.
Among other tests, the EPD tests the levels of substances like ammonia, phosphorous, fecal coliform bacteria and nitrogen at five sites on the lake and five tributaries of the lake regularly, Cutcliff said.
This spring, all those tests have returned results that were well within the EPD’s established limits for good water quality. He said results from tests in 2008 also met the EPD’s standards, although he has not compared the results from the two seasons.
"Everything that we’ve seen so far said that it (the higher water levels) has had a positive effect," Cutcliff said. "There do not appear at this time to be any negative issues to having the water levels raised."