RALEIGH, N.C. (May 23, 2011) – The N.C. Wildlife Resources Commission will stock Lake Norman with 177,500 striped bass in early June—15,000 more fish than is normally stocked into the reservoir every year.
The additional fish, which measure 2 to 3 inches in length, are being stocked to help compensate for the loss of fish during a July 2010 fish kill.
After the fish kill, biologists collected more than 7,000 dead striped bass and assumed that another 20 percent, or 1,400 fish, were picked up by other people or sank to the bottom of the reservoir. Assuming 8,400 striped bass died and using harvest rates and natural mortality rates estimated for striped bass in other Southeast reservoirs, they determined that stocking 15,000 additional fish would return catch rates to where they would have been in 2013 if the fish kill last summer had not occurred.
“Two years, or 2013, is the time frame because it takes two years for stocked fish to reach 16 inches or harvestable size,” said Brian McRae, Commission Piedmont Region Fishery Supervisor. “If the fish kill had not occurred in 2010 and 8,400 harvestable-size striped bass were still alive at the time of the 2011 stocking, between 1,445 and 2,156 of those fish would still be in the reservoir in 2013, based on the range of harvest and natural mortality rates documented for other Southeast reservoirs.
“So, if we stock an extra 15,000, 2 to 3-inch striped bass in 2011, we calculate that an additional 2,000 harvestable-sized striped bass will be in Lake Norman by 2013.”
Last summer’s fish kill in the 32,500-acre reservoir, located in Iredell, Catawba, Lincoln, and Mecklenburg counties, was a natural event that occurs frequently in deep reservoirs in the Southeast, according to McRae.
“The depth of Lake Norman, over 100 feet at the dam, ensures that the water column stratifies into three distinct layers each summer,” McRae explained. “As summer progresses, isolated pockets of dissolved oxygen form in the bottom layer initially sustaining fish; however, these pockets eventually shrink and dissolved oxygen declines below levels that can be tolerated by striped bass.
“This ecological process occurs annually in Lake Norman and many other deep reservoirs in the southeast, including Badin Lake in North Carolina. We are still assessing the specific conditions that result in mortality in some years but not others.”
Because the Commission stocks approximately 162,500 striped bass in Lake Norman each year, McRae says they are confident that the fishery can recover from these fish kills if they happen infrequently.
“Hopefully, the supplemental stocking this year will help mitigate some of the loss that occurred in 2010,” McRae added.
For more information on fishing in public, inland waters, visit http://www.ncwildlife.org/Fishing.aspx.