Wisconsin chinook harvests up 47 percent

[Lee Borgersen]

Wisconsin chinook harvests up 47 percent; outlook good for 2011
April 15, 2011 at 01:13 Am

Wisconsin DNR 

MILWAUKEE—Lake Michigan anglers had a banner year of chinook fishing in 2010, with favorable winds and other factors helping to increase harvest 47 percent, state fishery officials say.

“It looks like our chinook salmon harvest by Wisconsin anglers was really good in 2010,” says Brad Eggold, the Department of Natural Resources fisheries supervisor for southern Lake Michigan, who just completed analyzing surveys of what anglers caught on that water in 2010. “I don’t see any reason that 2011 would not be another solid year.”

Eggold found that anglers harvested 315,294 chinook salmon from Lake Michigan in 2010, up from 214,621 in 2009 and 256,796 in 2008. More good news for Wisconsin anglers: they accounted for the bulk of the lake-wide haul.

“Total chinook salmon harvests reported by all agencies in Lake Michigan was 531,170 fish. Wisconsin angler harvest comprised 60 percent of the total, so we did extremely well in 2010,” Eggold says. “It looks like it was very good fishing on our side of the lake in 2010 with favorable wind conditions throughout most of the summer.

“If we get westerly winds and cooler water like we did in 2010, we’re going to see good harvests of salmon and trout in 2011.”

The 2010 harvest is lower than the average chinook harvest in the preceding five years (344,077) but is much higher than the average from 1988-2001.

Eggold says that the chinook salmon may have benefitted from a large number of young alewives produced in 2010; recent years have seen smaller year-classes of the invasive species. Because of the smaller year-classes of alewives and the overall decrease in the forage base, all the agencies around the lake reduced chinook salmon stocking starting in 2006. “This lakewide reduction in stocking looks like it was a good move and is paying off with better chinook growth and survival,” he says.

DNR and counterpart agencies cut stocking levels by 25 percent to better match the number of predators in the lake with the declining forage base. In 1989 the estimated combined lake-wide biomass of four forage species in Lake Michigan hit a peak of around 770 million pounds, most of it bloater chubs. Today, the total is less than one-seventh that.

In the 1970s, the prime suspect in the decline of native species was alewives where today quagga mussels and zebra mussels are usually blamed for changes in the ecosystem, according to U.S. Geological Survey research.

The invasive mussels feed on plankton at the base of the food chain. Quagga mussels are considered even more damaging than zebra mussels because they can live in a wider range of water temperatures, water depths, and they feed most of the year, even in winter when zebra mussels lie dormant.

The lake-wide stocking reduction is also showing up in improved condition of the chinook handled at the Strawberry Creek egg collection facility during fall, according to Scott Hansen, DNR fisheries biologist in Sturgeon Bay.

“The lake-wide reduction in stocking has taken full effect now and it seems to be working,” he says. “We’ve started to see the weights creep back up again.”

The condition stayed about the same or was slightly down from 2009, but is still significantly better than in 2007, “when we hit historical lows for weight at age for females,” Hansen says.

The average weight for 3-year-old-plus females in 2010 was 5.9 kilograms, down slightly from 6.08 kilograms in 2009, but up from 2007’s 4.87 kilograms.