Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: MONDAY, November 7, 1994 TAG: 9412270004
SECTION: SPORTS PAGE: SPORTS EDITION: METRO
SOURCE: BILL COCHRAN OUTDOOR EDITOR
DATELINE: LENGTH: Medium
"Some right now are about 4 to 5 inches long and some are 7 to 9," said John Ney, professor of fisheries ecology at Virginia Tech.
That brings up a couple of pertinent questions:
Why are some of the stripers that were stocked this year growing so much faster than others? And are those small ones going to have enough fat reserve to survive winter?
These are the kinds of questions Ney and fellow researchers hope to answer during a three-year study sponsored by Tech, the Electric Power Research Institute, Appalachian Power Co. and the Department of Game and Inland Fisheries.
"Basically, we are doing this to try to ultimately make striper fishing better," said Ney, who is the project leader.
Fishermen have been complaining about a declining striper population in the 20,000-acre lake. Many believe more fish should be stocked. The stocking rate of the past decade has been about 300,000 fingerlings annually, well under the 809,000 of 1979.
But research conducted by Ney in the '80s revealed that survival of fingerlings dropped significantly when more than 300,000 were stocked.
"In fact, it may be poorer to the point that stocking more fish might translate into fewer adults," Ney said.
Fishermen often have difficulty understanding this concept, which Ney calls "a density-dependent relationship.
"It usually means one of two things," he said. The newly stocked fingerlings could be competing for food to the point that growth is retarded and there is a lack of stored fat for winter survival. Or the more you stock the more predators are attracted, which results in increased mortality.
"It is probably one or the other of those things," Ney said, explaining that the research is designed to come up with some answers.
This is believed to be the first striper study of its kind in the country.
"No one has set out to see: Where do they go? What do they eat? How big do they get their first year of life?" Ney said.
Trent Sutton, a Ph.D. candidate at Tech, and researcher Steve Sammons have been collecting young stripers for analysis with gill nets and electro-fishing gear.
"We have been pretty successful at staying with them so far," said Ney.
Sutton has discovered that the small fish have stayed close to the spots where they were stocked, while the larger ones are more likely to be found scattered in open water.
State officials stocked two sizes of stripers, about 300,000 of the traditional 1- to 2-inch fingerlings from the Game Department's Brookneal hatchery and about 35,000 3- to 4-inch phase II fish that spent time in Tech's aquaculture center.
The idea was to determine if larger stripers enjoy better survival.
"The bigger ones, I'd say, are definitely phase II," Sutton said, adding that the study has a long way to go before solid proof is available. Researchers hope to find out for certain when samples are studied in a laboratory.
"One of two things could have happened," said Ney. "They [the big fish] could be phase II fish or it could be when we stock at a particular site a certain percentage of the fish move out and feed better. What we have found,is a significant portion of what gets stocked stays close to where it was stocked during the first year, and the ones that stay close aren't getting into the feeding of alewives and shad."
While the lake's threadfin shad population is down, the result of a winter die-off, data now shows that the number of gizzard shad and alewives is higher than than preliminary information indicated, said Michael Duval, fisheries biologist supervisor for the Game and Fish Department.
"One of the things we are going to be playing with next year, is to stock the same number of stripers but put them in more sites," said Ney.
The stripers have been stocked at two sites during recent years, Hales Ford Bridge and Penhook Dock.
"We may go to four or six sites and just spread them around," said Ney. "Just on the surface, that would seem the sensible thing to do, anyway."
If the phase II fish prove to have significantly better survival, Ney said, then the question becomes: Is it economically feasible to raise bigger fish?
"You either stock bigger fish or you stock smaller fish earlier," he said. "Either way would probably require some significant changes in how the state raised them. They would probably have to maintain brood stock all year instead of just getting stock from the river during the spring spawn."
by CNB