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Taking a peek at the Portage-Torch Lake Chain/Tom Rozich

Biological Bits

July 26, 2013
By Tom Rozich - For the Gazette , The Daily Mining Gazette

The Portage-Torch Lake Chain (PTLC), also known as the Keweenaw Waterway, connects Keweenaw Bay with Lake Superior, effectively creating an island. In 1865 the U.S. Government awarded 450,000 mineral acres to the Portage Lake and Lake Superior Ship Canal Company to construct two miles of channel to Lake Superior on the north and dredge a channel down to Keweenaw Bay. The 22-mile waterway was completed in 1874 and allowed expansion of copper mining through shipping.

The PTLC is a system of lakes and channels of just over 13,200 acres (Portage-80 percent/Torch-20 percent), not including the Portage River and South Entry. Portage Lake and Torch Lake have maximum depths of 54 feet and 115 feet and average depths of 24 feet and 56 feet, respectively. Both have had millions of tons of stamp sands and mine tailings dumped into them by the copper mining industry. Torch Lake alone received 200 million tons, which displaced 20 percent of its volume. Torch at one time was 160 feet deep and had a lake trout population. Despite this, both lakes have excellent fisheries.

In April-May of 2007 the DNR Fisheries Division conducted an intensive fish survey using trap and fyke nets, seines, electrofishing and included the tagging of walleye, pike and smallmouth bass. The tagging was done to get population estimates, angler catch rates, and movement. This was followed by a creel census, where a DNR employee interviewed anglers about what they caught, how long they fished, etc.

The survey resulted in 37,813 fish being collected, of 37 different species including walleye, pike, perch, bass (large and smallmouth), four kinds of suckers, eight kinds of minnows, two kinds of bullhead, two kinds of whitefish, two kinds of lamprey, brown, brook, and rainbow trout, Coho salmon, rock bass, sunfish, bluegill, crappie, burbot, carp, smelt, alewife, ruffe, and lake sturgeon. Notably absent were musky and sauger. Musky are present in the PTLC, but in very low numbers. Saugers are now believed extinct, which we will discuss later.

The catch included 5,699 walleye, which ranged in size from 9.5 to 30.7 inches and averaged 20.9 inches. The walleye are fast-growing, being 2 inches above state average, thus many of them grow to 15 inches, after two summers. Almost 2,000 pike were handled, ranging from 8.2 to 44.1 inches and averaged 23.7 inches. The pike are likewise fast-growing and reach legal minimum at age 4. Only 115 smallmouth were collected, ranging from 2.5 to 16.1 inches. This is not an indicator of the total population, as they are not susceptible to collection in the spring.

The angler creel survey revealed that fishing effort is down dramatically. The 2007-08 survey estimated 42,724 hours, while a similar survey in 1973 had 139,590 hours, which is a 300-percent plus reduction. Most fished the summer open water (73 percent), and targeted walleye (78 percent). Of the 31,206 fish caught, 16,380 of those were walleye.

Saugers, a cousin of walleye and perch, are now presumed extinct in the PLTC. In the 1950's and 60's they were very numerous. In 1960 DNR placed a bag limit of 20 in response to lower catch rates and in 1968 placed a minimum 13 inch size limit and bag of five on sauger. The last reported sauger caught was in 1980. Their demise is thought to be due to contaminants, degraded spawning grounds, and lower turbidity (clearer water) after mining operations stopped and sewage treatment plants were constructed.

The tag returns are very interesting, especially for the walleye. A total of 4,777 walleye were tagged with metal jaw tags. To date just over 550 have been returned. Most were caught in the PTLC, as walleye are not nomadic, but 19 were caught out of the PLTC. Twelve were caught in Keweenaw Bay, three were taken off the mouth of the Ontonagon River, one at the mouth of the Montreal River, in Keweenaw County, two returns came from the Apostle Islands, Wis., and one from the Brule River, Minn. The Brule River is in the arrowhead of Minnesota, a few miles from the U.S./Canada border. Straight-line distance is 100 miles, but is more like 400 along the shore.

The PTLC fish survey turned up a walleye that was tagged in 2002 in the Nipigon River, Ontario, a straight line distance of 150 miles, but would be 600 miles along the coast. A few adventurous walleye wonder if they had passports?

Go Fish!

 
 

 

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