Adminstrative Technician, Laurie Gucinski, carefully climbs into tank to check for a light tight seal while Hatchery Manager, Dale Bast, secures the ladder.

Dale Bast listens for instruction from Laurie Gucinski from inside the tank.

The Iron River National Fish Hatchery produces 1,600,000 lake trout and 315,000 brook trout for stocking into the Great Lakes each year.  This happens in part due to the 4,000 coaster brook trout and 3,000 lake trout brood stock housed on site.  At the hatchery, there are two strains of lake trout and two strains of coaster brook trout.  The brook trout strains are from populations found in the wild around Isle Royale, an island in Michigan waters of Lake Superior, namely Tobin Harbor and Siscowet Bay strains.  Every two to three years fish biologists from the Ashland FRO, Genoa NFH and Iron River NFH set out to collect gametes from the wild population and this year the target strain was Tobin Harbor.  If all goes as planned, 15 sexually mature females and 30 males are collected and held until ready to spawn, eggs are collected, divided and fertilized to make 30 different family pairs and then transported by ferry back to the mainland for transport to Genoa NFH for isolation.  Of course, it rarely goes as planned.

Sometimes the fish and or the weather don't cooperate and all that hard work doesn't pay off.  Usually, when troubles occur with fish collection in the wild it is due to not collecting enough mature/ripe females to make a new brood stock.  Every best laid plan needs a back-up, which is where the creative thinking of the Iron River NFH staff came in.  In the event that not enough females were collected on Isle Royale, milt (fish sperm), which is viable for up to a week after collected, was to be transported to the Iron River National Fish Hatchery to fertilize Tobin Harbor brood stock eggs on the mainland. 

Wild fish found in Tobin Harbor spawn in mid October but at the Iron River National Fish Hatchery, they spawn in mid November.  (Two key factors that trigger spawning in fish are photoperiod and water temperature.)  Hatchery staff acquired two surplus round tanks from Genoa NFH, outfitted each with a light-tight lid and revamped them to accommodate 15 females each.  Biologists calculated the difference in day length from the month of October (wild spawning) to November (hatchery spawning) and started to accelerate the photoperiod of the fish.  This was done over a six week period by closing the light-tight lids on the tanks and increasing the amount of darkness week by week.  By mid-October, the goal was to convince the fish that it was mid-November and time to spawn, coinciding with the wild population.  The photo-acceleration was a success and the females matured in October.  However, the crew on Isle Royale was able to capture the prescribed amount of fish, create 30 brood families and transport them to the mainland for travel to Genoa.  Once at Genoa, the eggs will hatch, and the fish will be held in isolation for 18 months.  During the 18 month period, the fish will be tested for diseases three times until a clean bill of health is achieved before they can be transported to the Iron River National Fish Hatchery.  Stay tuned to find out the outcome of what has been a very successful venture.