Hatchery Fish Biologist Nick Grueneis collects milt from a lake trout male for shipment to Sullivan Creek NFH. - FWS photo

Iron River National Fish Hatchery recently did something rather odd with milt that was collected from its male lake trout.  Over a three week period, next day commercial air freight was used to deliver the lake trout sperm to Sullivan Creek National Fish Hatchery for use in the fertilization of lake trout eggs.  

Both hatcheries maintain multiple strains of lake trout brood stocks.  The Klondike strain of Lake Superior lake trout is currently at both stations.  The fish at Iron River are not yet old enough to produce eggs, but are old enough to produce sperm.  The fish at Sullivan Creek are all the same age or year class.

To ensure the best possible mix of genetic material, Service fish biologists decided to use sperm from the Iron River fish to fertilize the eggs from the Sullivan Creek fish.   The entire process was not difficult, but did require quite a bit of coordination between the two facilities and with the commercial delivery company.

Sullivan Creek fish biologists would check their female lake trout early Monday mornings and notify Iron River how many were ready to spawn (this is done by feeling the abdomen of the fish).  In turn, Iron River fish biologists would collect sperm from an equivalent number of male lake trout. 

The milt was stripped into special plastic bags, filled with pure oxygen and placed into a chilled container for shipping by overnight delivery.  The following day, the sperm arrived at Sullivan Creek and was used to fertilize eggs collected from female lake trout.  In all, 151 male lake trout were used for this process which occurred over three separate weeks in October. 

The newly fertilized lake trout eggs were packaged in special shipping containers and shipped to White River National Fish Hatchery in Vermont.  The eggs will be incubated and hatched at White River and if all goes according to plan, result in 250,000 yearling lake trout for stocking into the lower Great Lakes.

This project is just one example of the constant cooperation and coordination that occurs between and among programs in the US Fish and Wildlife Service.  We are proud to work with each other especially for the benefit of lake trout in the Great Lakes.