Kalamazoo Streamside Rearing Trailer
Waiting for its Precious Cargo
BY DOUG ALOISI, GENOA NFH
Spring is finally inching its way into the Lower Peninsula of Michigan, and with its arrival one of the state's most fascinating aquatic creatures, the lake sturgeon, are inching their way up their natal rivers to spawn. This brings a flurry of activity on the banks of the Kalamazoo River, one of the few remaining Lake Michigan tributaries that have a small remnant population of lake sturgeon remaining.
Lake sturgeon populations throughout their historic range have been severely reduced due to overfishing, reduced available spawning habitat due to river obstructions, and pollution reducing suitable water quality. The sturgeon's unique life history also extends the time it takes populations to recover, with females not reaching spawning ages until they are over 20 years old.
Federal, state and tribal agencies and conservation groups came together in the Kalamazoo River and formed a partnership to ensure that the Kalamazoo strain of lake sturgeon did not disappear. In 2011, the maintenance staff from the Genoa National Fish Hatchery (NFH), located in Wisconsin, constructed a streamside rearing unit to be deployed on the banks of the Kalamazoo River, to use river water as a culture source for lake sturgeon eggs and fry. The eggs and fry are captured by state, tribal biologists and volunteers from the Kalamazoo Chapter of Sturgeon for Tomorrow and brought into the trailer for rearing until they are large enough to avoid most predators.
Lake sturgeon early life history mortality is very high, with many different species of fish and crayfish delighting in a caviar dinner every spawning season. The streamside rearing unit keeps eggs and fry safe from predation, while at the same time providing river water for the fish to be reared on, which will help them navigate back to their birth site 20+ years later. The streamside rearing trailer can raise up to 1500 8 to 10 inch lake sturgeon fingerlings for release back into the Kalamazoo annually. The fingerlings have been found to survive very well, and with continued year classes being released, it is hoped that a spawning population containing many year classes of sturgeon can be restored.
As the spring season has been prolonged this year, biologists have had time to prepare the egg traps, fry drift nets and gear to increase the chances of getting enough eggs and fry to fill the trailer. This month the trailer was taken out of storage and placed streamside to wait for water temperatures to climb to over 50 degrees, the temperature when spawning activity commences. Culture systems were tested and all maintenance checks performed to ensure that a healthy cargo of sturgeon will be the result of this year's trailer operations on the banks of the Kalamazoo.