Delta Marsh recovery project

Delta Marsh is a internationally recognized wetland that has changed dramatically for the worse since Hollywood film legend Clark Gable visited Jimmy Robinson’s Sports Afield Lodge along the shore of Lake Manitoba. Upon arriving at the lodge on September 23, 1938, the impatient silver screen heartthrob said to his host: “Let’s go hunting now ... I want to take a look at those ducks I’ve been hearing so much about. Tomorrow’s too long to wait.” 
When Gable, Robinson and guide Rod Ducharme reached the boat they would be using, the Hollywood star was so anxious to reach the hunting grounds that he took the paddle and with strong strokes, set out to reap the bounty of the marsh. “Mallards, canvasbacks and widgeons winged their ways over our heads,” Robinson wrote. “The air was full of ducks. The huge marsh was alive with waterfowl. A golden September sun, reflected on rushes and wild rice, lent color to the scene.”
The hunting party set up their decoys  in a little pothole and pushed their boat into the reeds, which acted as a blind. 
“‘Boy, oh boy!’ Gable exclaimed (Free Press, September 26), almost turning over his flimsy duck-hunting boat in his enthusiasm. ‘I’ve done it at last!’
“‘I’ve fulfilled my life’s ambition, Jimmy,’ Clark shouted,” according to Robinson’s account of the hunt, which appeared in Minneapolis-based Sports Afield magazine in December that year. “‘I’ve always wanted to shoot the limit of canvasbacks in a single day — and boy, oh boy, I’ve done it at last!”
Gable was described by the Free Press as “grinning and happier, perhaps, than he had ever been before in his life.”
While paddling back to their camp, Robinson wrote: “Hundreds of mallards, canvasbacks and widgeons whizzed over our heads to settle in the potholes and bayous of the great marsh.
“Gable liked our Manitoba marsh country,” Robinson continued. “Every day we visited a different section of the marsh. In spite of the warm summer days, the birds were flying early in the morning and in the evening — the cream of the waterfowl population of the entire continent.
“‘I didn’t know there were so many ducks in the world!’ said Gable.”
In fact, there were so many ducks that American sportsmen and local businessmen established a number of hunting lodges at Delta Marsh. Mallard Lodge, which now is part of the University of Manitoba Delta Marsh Field Research Station, was built in 1932 by Winnipeg businessman Donald H. Bain.
Today, duck numbers have greatly diminished and hunting is strictly controlled at the marsh. The  days of mass shooting of ducks have been over for decades. But the diminishing numbers are also known to be influenced by environmental factors, such as the invasion of hybrid cattails that exclude plants favoured by ducks, as well as the proliferation of carp, which uproot duck-friendly vegetation. The fish’s aggressive eating habits and enthusiastic mating in the shallow marsh during the spring, dredges up silt, turning the water cloudy, which blocks the sunlight needed for native plants living along the bottom of the marsh to grow. The loss of plants, which are required to keep the soil in place, leads to further erosion. 
Studies conducted by the University of Manitoba’s Delta Marsh Field Station between 2001 and 2004 have also “shown the presence of carp increases the levels of phytoplankton and suspended sediment in test pools” (Alternatives: Canada’s Environmental Magazine, September 29, 2009). The phytoplankton robs the water of oxygen, killing fish and insect larvae. The only fish that can survive this low-oxygen environment are common carp, an invasive species to Manitoba, which is known to come to the water’s surface and gulp oxygen. With the insects gone, ducks have no protein available to feed their hungry hatchlings.
Recently, the provincial government and Ducks Unlimited Canada announced a $3.5-million project that includes keeping carp out of the marsh — there is absolutely no way to permanently remove the fish from most of Manitoba’s waterways as they’re the  most numerous of all fish in the province.
Fortunately, there are entry points from Lake Manitoba that can be blocked by fish screens to keep the carp at bay, and these only have to be in place during the carp’s breeding season, as the fish overwinter in Lake Manitoba. “The placement of screens will be timed to allow the movement of native species, such as walleye (pickerel), that use the marsh to spawn earlier in the spring,” according to the press release announcing the project.
“Scientists have discovered the damage caused to Delta Marsh to be largely reversible, so immediate action is needed to restore Manitoba’s premier marsh back to its continental importance,” said Ducks Unlimited Canada CEO Greg Siekaniec.
Common carp, a relative of goldfish, are native to Europe and Asia, and were unwisely introduced into Manitoba as a food fish in 1886. But they were immediately shunned as food, since the bottom-feeding fish tasted of mud. At the time of Gable’s visit to Delta Marsh, carp had not spread that far, which helps explain the profusion of waterfowl. But by the 1940s, carp had penetrated the Red River. In the 1950s, carp were found in the south basins of lakes Manitoba and Winnipeg. Since 1976, carp have spread throughout most of Manitoba’s lakes and streams, and now are found in the Churchill River system. The fish is listed among the top-100 most invasive species in North America.
“Manitoba’s Delta Marsh ... has been recognized as a Wetland of International Importance for decades,” said Conservative and Water Stewardship Minister, Gord Mackintosh. “Scientists tell us wetlands like Delta Marsh are the ‘kidneys of our province,’ because of their ability to filter out pollutants out of our waterways.”
“Our experiments in small areas within the vast Delta Marsh have shown remarkable recovery within a few weeks of excluding carp ...,” said Dr. Gordon Goldsborough, associate professor of biological sciences at the University of Manitoba. “We are confident that substantial improvement in Delta Marsh can occur this year and look forward to seeing for the first time what can be accomplished at this unprecedented scale.”
On November 15, 1938, Gable wrote Robinson: “Needless to say I had a marvelous time up there (Delta Marsh) ... When I told Harry Fleishman about the canvass back (sic) and mallards he looked at me with a rather dubious eye, however, having seen as many as I did I had a convincing ring in my voice. I know, because all the guys here are now saying, ‘When you go up there again take me with you ...’”
With the new project protecting Delta Marsh from destructive carp,  “the huge marsh” may once again be “alive with waterfowl,” as was the case when Clark Gable visited in 1938.