DNR Studies Prospects for Sustainable Lake Herring Fishery in Lake Huron
February 19, 2009
Department of Natural Resources fisheries biologists are in the process of analyzing a three-year pilot project to determine whether stocking lake herring in Lake Huron is feasible. The initial assessment is that it just might be.
Historically, Lake Huron boasted an enormous population of lake herring -- also known as cisco -- that provided both recreational and commercial fisheries as well as serving as an important prey species.
Lake herring shouldn't be confused with the small oily fish found in the North Atlantic (genus Clupea). Lake herring belong to the genus Coregonus, which includes lake whitefish, and once made up one-third of the total take of commercial fish in an average year.
"They're still there, but at a fraction of what they used to be," said DNR fisheries biologist Dave Fielder, who is working on the project out of the Alpena Fisheries Research Station.
Lake herring populations declined with the rise of alewives, which probably out-competed the native herring in the lake as both are pelagic planktivores, Fielder said. Pelagic planktivores are plankton-eating fish that swim continuously in open water, usually well offshore.
Now with a significant decline in alewife numbers, it might be possible to reestablish lake herring, he said.
Although some recreational fisheries still exist -- most notably around Lime Island and below the power plant on the St. Marys River -- herring populations are mere shadows of their former levels. They are absent from some places, such as Thunder Bay and Saginaw Bay, which were important spawning and nursery areas and where they once provided fisheries.
"We have seen some range expansion, but they're totally absent from some places where they once were abundant," Fielder said. "Obviously if we don't have any brood in those areas, we're not going to get much population growth. The alternative to stocking is to let them colonize, but because they return to their home areas to spawn, that could take a very long time."
Reestablishing herring populations could not only create new recreational fisheries, but also might help in the rehabilitation of other sport fish, such as salmon, which are struggling because of the lack of alewives. Herring are an important prey for lake trout -- which have become the alpha predators in the open water of Lake Huron -- and are utilized by salmon in Lake Superior and elsewhere.
Although herring fingerlings have been successfully raised in hatcheries, they've never been raised in big numbers. The purpose of the pilot project is to see if it can be done.
The project, which began in 2006, involves collecting eggs and fertilizing them, then growing the fish at the Wolf Lake State Fish Hatchery near Kalamazoo.
Of the two tasks, Fielder said collecting the eggs has been harder.
"They're pretty easy to raise," said Matt Hughes, DNR biologist at Wolf Lake. "They do really well in the hatchery."
When water temperatures drop in the fall, the lake herring forms large spawning schools. With the help of biologists from the Chippewa-Ottawa Resource Authority, DNR crews have been collecting eggs along of the shore of Lake Nicolet on the St. Marys River. In 2006, the crew collected a lot of eggs in early November, but found the eggs were not mature enough to be fertilized.
In 2007, collecting eggs about a week later than the previous year, the DNR crew managed to get some of them fertilized and raised to eye-up (stage in development when the eyes of the larval fish can be seen), "but we concluded we were still too early," Fielder said. "We got about a six percent eye-up and ended up with about 6,000 fingerlings."
The fingerlings were marked with oxytetracycline and planted in Thunder Bay in June. DNR crews will be on the lookout for those fish when they conduct their usual fish surveys on Lake Huron.
In 2008, the herring were collected during the firearms deer season.
"The fish were basically ripe," Fielder said. "The hatchery staff reported a much better eye-up after experimenting with some new ideas."
The eggs were divided into two rearing areas -- one with ambient water, the other in chilled water.
"We got 11 percent eye-up in ambient water, but 56 percent in cold water," Fielder said. "It appears they have to be in very cold water to mimic what they have out there in the wild."
Fielder hopes Wolf Lake will produce 100,000 fry from the 2008 effort.
"The number of fingerlings we wind up with might be much higher than last year, but that's not really the goal," Fielder said. "This is probably the last year we'll do this -- we feel like we've learned enough to go into production.
There's a kicker, however.
Although restoring native fish species is one of the Fisheries Division's highest priorities, Northern Lake Huron Fisheries Supervisor Dave Borgeson said the objective of the project was to see if biologists could successfully spawn and raise the fish.
"Our capacity for full-scale production depends on many factors, probably the greatest of which is available budget," said Borgeson.
The DNR also has watched Lake Huron's food web change drastically in recent years, according to Lake Huron Basin Coordinator Kurt Newman.
"The ecosystem continues to change rapidly, mostly due to invasive species. Whether we're talking about lake herring or other species, we need to align our management with the lake's situation," Newman said.
"Our goal is to provide a healthy, functioning Lake Huron ecosystem that ultimately provides stable fisheries. In the case of lake herring, that starts by restoring a self-sustaining population."