Earlier this summer Lake Norman received its fifth batch of hybrid striped bass via an annual stocking program started by the N.C. Wildlife Resources Commission (NCWRC) in 2013. In case you are not familiar with hybrid stripers, the fish come from breeding striped bass with white bass at government-operated hatcheries. The species has proven it’s better suited than stripers to handle hot water and poor dissolved oxygen levels found in southeastern lakes during summer months.
This capability is why hybrids were chosen to replace striped bass in Lake Norman, where the water warms naturally in summer to 90 degrees, plus two power plants discharge hot water into the mix. Add in periods of low flow, and you’ve got a deadly scenario for true stripers. Lake Norman has experienced a number of well-documented and significant striper die-offs this century.
Beginning in December 2015, the NCWRC, with the help of many volunteers, initiated a tagging-recapture program for Lake Norman’s hybrids. The data from these efforts is used to better understand the viability and distribution of the new hybrid population and to help determine future stocking rates.
The quantity of hybrids delivered to Lake Norman over the last five years is 162,500 each year from 2013-2015; 265,000 in 2016; and 307,000 in 2017. The 162,500 number is a volume that’s been used for LKN striper stockings for many years, equating roughly to five fish per acre.
From more than a million hybrids stocked as of July 2017, 732 hybrids have been tagged and released in Lake Norman. Of those, 314 fish (42.9 percent) have already been recaptured, which the biologists say is a high value for most tagging programs.
Of the reported recaptures, 140 hybrids have been caught by bank anglers, and 174 fish were taken by fishermen in boats. Of the recaptured fish, 92 percent of those caught by bank anglers were kept, presumably for consumption, and 58.3 percent were kept by boat fishermen. The balance of each were released again after removal of the tags.
As for how the fish are distributed across the lake, data shows that the most taggings and recaptures so far have come in the river section of the lake, defined in the study as upstream of the U.S. 70 bridge to Lookout Shoals Dam. This activity is heavily skewed to spring months.
The second-most taggings have come in fall and winter in the upper section of the lake from the N.C. 150 bridge to the U.S. 70 bridge. The second-most recaptured fish have come from the mid-lake section, from Marker 10 to the N.C. 150 bridge in winter. The lower lake section from Cowans Ford Dam to Marker 8 shows by far the least tagging or recapture activity.
The biologists say they have not yet calculated harvest rates for the entire hybrid population, but I think I can deduce a few unscientific conclusions from the data and my time on the water. First, the hybrids are getting caught and taken out of the lake at a far faster rate than the original stocking level supports.
Second, the hybrids are very well in tune with current, which on Lake Norman means the power plant discharge canals and the river section. Flows from both are intermittent, but the fish really push up into the current when the water is moving.
Thirdly, to date all stockings have taken place on the upper end of the lake. I’m guessing over time the hybrids will spread across the lake, but it seems that stockings in the middle and lower lake sections would greatly speed that process.
Unfortunately, production capacity at the hatchery is a limiting factor that may prevent much higher stocking rates in the future. I say bring ‘em on, the more the better.
Finally, for more specific info on the Lake Norman hybrid tagging program, visit this previous article at http://bit.ly/2xrV8gs.
Capt. Craig Price of Denver owns Fish On! Lake Norman, a fishing guide service.