Nick Starzl, Genoa National Fish Hatchery, nets brook trout out of a fyke net in Tobin Harbor. Photo by Glenn Miller, Ashland NFWCO

Gamete Collection in Tobin Harbor a Success in 2008

Coaster brook trout (Salvelinus fontinalis) were once abundant throughout the nearshore waters of Lake Superior.  Except for Isle Royale, Michigan, and perhaps the Salmon Trout River, Michigan, coaster brook trout are functionally extirpated in U.S. waters of Lake Superior. 

In 1995, in anticipation of future rehabilitation needs and as a precaution to preserve the genetic diversity of coaster stocks of undetermined size at Isle Royale, the U.S. Fish and Wildlife Service (Service) led an effort to collect gametes for development and maintenance of a broodstock of native Lake Superior Isle Royale strain coasters.  Previous gamete collections occurred in 1996, 1998 and 2001.

Information gathered during gamete collection and assessment efforts in Tobin Harbor and Siskiwit Bay indicated several differences between the two coaster stocks.  The differences include both life history traits and genetic characteristics.  These differences led the Service to treat these stocks discretely and refrain from combining the two into a single broodstock pending further information. 

For the fourth time since the development of the plan, the Genoa and Iron River National Fish Hatchery (NFH) and the Ashland National Fish and Wildlife Conservation Office (NFWCO) collected gametes from Tobin Harbor.  The crew consisting of Nick Starzl, Genoa NFH, Glenn Miller, Ashland NFWCO and Anna Varian, Research Technician from Northern Michigan University, Marquette, Michigan, headed to Tobin Harbor, Isle Royale National Park on the Ranger III. 

Fish were collected by setting fyke nets in known areas that brook trout spawn.  A total of 6 fyke nets were set for 5 consecutive nights, October 17 – 21.  The initial three nights had fish being held in anticipation of the females being ripe for spawning and males had their milt collected and refrigerated to preserve viability of the sperm.  Ripe males and females from the  last two days of netting were held for the spawning event the morning of the 22^nd of October.  A total of 17 new “families” were created from this effort.  The eggs collected will be reared at Genoa NFH for a quarantine period, and then individuals for the new broodstock line will be delivered to the Iron River NFH for future spawnings.  Along with the new progeny for the recovery effort a total of 118 brook trout were handled in Tobin Harbor: 53 males, 49 females and 16 juvenile fish. 

To date Tobin Harbor strain brook trout have been stocked in the Keweenaw and Huron Bay areas in Michigan, Whittlesey Creek in Wisconsin, and Grand Portage, Minnesota.  Brook trout had been stocked in the Pictured Rocks National Lakeshore near Munising, Michigan, but this stocking was ceased due to potential presence of remnant stocks in area streams.  The stocking in Whittlesey Creek is part of a effort to examine and compare the success of both Isle Royale strains, Siskiwit River and Tobin Harbor.