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Entries in Great Lakes (112)

Wednesday
Nov122014

Atlantic Salmon Reproducing in Great Lakes

Atlantic salmon fingerlings. USFWS photo
A chance discovery by a college student reveals that Atlantic salmon are reproducing in the Great Lakes --- at least in the St. Mary’s River, which connects Superior and Huron.

“We were conducting research for my sturgeon thesis when we found the Atlantic salmon fry,” said StefanTucker, a Lake Superior State University graduate. “It was very exciting to everyone who was a part of my research to imagine what we had just stumbled upon.

“While sorting through my samples at the lab with Roger (Greil), we began to ID the salmonids and Roger had a suspicion that they were Atlantics,” he added. “We caught wild Atlantics in our next two sampling events, so we wanted to confirm our ID and we sent a few to Dr. Gerald Smith at University of Michigan, who confirmed the identification.

Atlantic salmon (Salmo salar) are native to Lake Ontario, but their populations severely declined by the late 1800s, according to Tucker’s abstract. During the early to mid-1900s, Atlantic salmon were stocked throughout the Great Lakes in effort to reestablish them into Lake Ontario and introduce the species into the upper Great Lakes. However, these efforts had minimal success.

In 1987, LSSU, in cooperation with MDNR Fisheries, began stocking Atlantic salmon in the St. Mary’s River. While the effort has resulted in a very successful recreational fishery, along with an excellent educational experience for students, it appeared that Atlantics were still not reproducing naturally even though they would return to the river spawning grounds every year. Biologists wondered if competition from other salmonids spawning in the St. Mary’s in greater numbers – including chinook and pink salmon – was keeping Atlantics from thriving.

While this is the first documentation of natural reproduction of Atlantic salmon in the upper Great Lakes, Tucker’s study concludes that “the extent of natural reproduction and mechanisms influencing reproductive success are unclear and warrant further attention.”

Monday
Oct272014

Artificial Reef Projects Expand to Shallow Water

We’ve been using artificial reefs to improve habitat for fish and other aquatic life in deepwater ocean habitat for awhile now. But we’ve just begun to tap their potential in shallow water.

For example, artificial reefs finally are going to be deployed in Florida’s St. Johns River, following years of research and discussion.

“While the artificial reefs will not replace the natural system, they will help. The nooks and crannies will offer small spaces for small fish to hide and live. The concrete will provide a surface for marine growth to occur. Barnacles and oysters are expected to become established on the rocks,” says the Times-Union.

“Not only do they become potential food for fish, they also filter sediment and other particles out of the water, thereby improving water quality. The small fish become food for the larger fish, and so grows the food chain.”

Up in the Great Lakes, meanwhile, a spawning reef of four acres is being built in the St. Clair River, to benefit walleye, sturgeon, and whitefish.

The project at Harts light is the sixth spawning habitat built by the Michigan Sea Grant in the St. Clair and Detroit rivers

During the late 1800s and early 1900s, those systems were dredged to create deep shipping channels. In the process, 800 to 1,000 acres of prime spawning habit were destroyed.

And out in California, scientists have discovered that offshore oil rigs provide some of the most productive fish habitat in the world. They determined that the structures are home to 27 times as many fish as natural rocky reefs in the area.

Wednesday
Oct012014

Commercial Fishing Is Ally for Anglers in Battle Against Asian Carp

Kentucky Lake Asian carp. Photo by Steve McCadams

A recent study by University of Notre Dame researchers suggests that  consequences of an Asian carp invasion into the Great Lakes may not be as catastrophic as many fear.

“If bighead and silver carp were to establish in Lake Erie, local fish biomass is not likely to change beyond observations recorded in the last three decades,” the university said in a press release about the findings.

Scientists pointed out, however, that the study mainly highlights the uncertainty, adding that the walleye population could decrease by as little as 10 percent or as much as 40.

“The range of possibilities concerning walleye biomass shows that the potential effect to this species is highly uncertain,” said Roger Cooke, one of the study’s authors.

But what’s happening right now in Kentucky Lake and many more of the nation’s bass fisheries along major rivers is not theory. It’s reality.  The exotic fish are there in massive numbers. For example, a first-of-its kind commercial tournament on Barkley and Kentucky Lakes last year netted 82,953 pounds of bighead and silver carp --- that’s more than 40 tons--- in just two days.

And this reality does not bode well for the future of sport fishing.

“If we don’t do something, bass fishing will be over with in five to ten years. You won’t be able to run a bass boat on many of these waters,” said J.D. Johnson, owner of Gulf Pride Seafood.

“If people don’t wake up, we might as well hang it up.”

Working with Carp Management Group of America LLC, Johnson is at the forefront of an effort to garner both angler and financial support for commercial harvest of carp. And he’s not alone.

B.A.S.S. National Conservation Director Gene Gilliland also supports the effort, as do fisheries chiefs in Kentucky and Tennessee.

“Fishermen need to get behind this idea of commercial netting,” Gilliland said. “It’s the only viable solution until someone develops a magic pill.”

“We have to do something now before our lakes and rivers become so over-populated with Asian carp that our native fish never will be able to make a comeback,” said Tennessee’s Bobby Wilson.

“We may not be able to eliminate Asian carp by this method. But the goal is to reduce their numbers so that they will not have a significant impact on our native species of fish.”

Kentucky’s Ron Brooks added that the carp pose a dire threat to “the very base of the aquatic food pyramid” because they feed on phytoplankton and zooplankton, primary forage for newborn bass, crappie, and other sport fish.

The invaders pose that threat because of their massive appetites and huge numbers. A carp eats 5 to 20 percent of its body weight each day as it grows to an average weight of 30 to 40 pounds. A female can lay hundreds of thousands of eggs at a time, and she can do so multiple times annually.

Even knowing all this, however, some bass anglers likely are shaking their heads and saying that they don’t want nets in their waters. But Gilliland said commercial harvest does not harm sport fisheries --- even when gillnets are used.

Most significantly, however, gillnets aren’t the best way to harvest Asian carp, according to Johnson. “We call it ‘strike fishing’ and we’ve done it for years with mullet,” he said.

Schooling fish are encircled by net, driven inward, and quickly harvested. No nets are left unattended to snag whatever swims by.

“I can put 900 feet of net down to 200 feet in less than a minute,” Johnson said.

He added that he could send 575 metric tons of carp to Asian each year, if only the facilities were available to process them. Right now, though, harvested carp are used mostly for fertilizer and silage, and that’s not profitable enough to sustain an aggressive commercial fishery.

“In Tennessee, things are moving at a snail’s pace regarding commercial harvest, processing, and marketing of Asian carp,” Wilson said.

“Funding is the major issue, as it is with almost every venture.

“We know that commercial fishermen can catch them, and we know that there is a market for them overseas, as well as within the United States. The missing pieces are the processing plants and the price per pound for commercial fishermen.”

(This article appeared originally in B.A.S.S. Times.)

Thursday
Aug212014

Sky Isn't Falling, But Dead Zones Are Real

The Mississippi River dead zone is overloaded with nutrients from upstream sources. This photo shows the color change between the hypoxic (brown) and oxygen-rich (blue) waters. Photo courtesy of NOAA.

Climate change occurs naturally. It always has, and it always will vary from day to day, week to week, season to season, year to year, decade to decade, and century to century. Possibly humans play a role in that change in some way, but no verifiable evidence supports that. Even if it did, we, as one nation, could do little to nothing about it because our contribution is miniscule compared to what’s happening in China, India, and the rest of the world.

The billions of dollars wasted on this sky-is-falling hysteria could be far better spent on providing food and clean water to the millions who need it.

By contrast, dead zones pose legitimate threats to our fisheries and oceans and could be minimized if we changed our ways.

LiveScience.com reports the following:

“Agricultural practices are the biggest culprit for dead zones in the United States and Europe. Rains wash excess fertilizer from farms into interior waterways, which eventually empty into the ocean. At the mouths of rivers, such as the Mississippi, the glut of phosphorous and nitrogen intended for human crops instead feeds marine phytoplankton.

“A phytoplanktonic surge leads to a boom in bacteria, which feed on the plankton and consume oxygen as part of their respiration. That leaves very little dissolved oxygen in the subsurface waters. Without oxygen, most marine life cannot survive.”

In the United States, the most notorious dead zone occurs each summer in the Gulf of Mexico, spreading out from the mouth of the Mississippi River. This year, it consumes more than 5,000 square miles, slightly smaller than last year. On average, it is estimated to cost $82 million annually in diminished tourism and fishing yield.

More than 150 dead zones have been identified in this country, most of them along the coasts. A few occur inland, notably the Great Lakes.

Some of them have been cleaned up through improved management of agricultural runoff and sewage. But as fertilizer and factory farming both increase, LiveScience.com warns, “the United States is creating dead zones faster than nature can recover.”

More than 400 dead zones have been identified worldwide, covering about 1 percent of the area along continental shelves.  But likely many more than that exist, since portions of Africa, South America, and Asia have yet to be studied.

Thursday
Apr032014

Great Lakes Ice Good for Water Levels, Fisheries, But Could Mean Loss of Wetlands

NOAA photo collage

By mid February, ice coverage of the Great Lakes was at 87.3 percent, as scientists predicted that it would reach record proportions--- more than 94.7 percent--- before the spring thaw.

That can be bad for commercial navigation. But in general, the ice is good for the lakes and their fisheries.

“When you have more ice formation, you have less direct contact with the atmosphere, less opportunity for evaporation and that keeps the water levels up, said Alan Steinman of the Annis Water Resources Institute.

For years now, the lakes have suffered from low water, with Lake Michigan falling to record lows just last year. More water retained will mean more shoreline habitat later.

Yet that also could mean the loss of wetlands gained during the low-water years. From 2004 to 2009, wetlands increased by 13,610 acres in the eight-state Great Lakes region, according to the U.S. Fish and Wildlife Service.

That was the only portion of the country to show an increase, as the rest of the nation’s coastal wetlands shrank by 360,720 acres.

Before ice coverage started reaching record proportions, Donald Uzarski of the Institute of Great Lakes Research explained how the increase occurred.

“As the shoreline moves away from the upland, the wetland essentially follows it,” he said.

“Usually, the amount of wetlands stays the same over the years as water levels rise and fall because wetlands move where the shoreline is. But we’re seeing low levels that have rarely happened in the past.”

Going into spring, water levels likely will be higher than they would have been following a mild winter, thanks to that ice coverage. It increased from 77 to 87.3 percent during the second week of February and was forecast to reach the highest percentage since records started being kept in 1973. Coverage of 94.7 percent was recorded on Feb. 19, 1979.

By Feb. 12, Lake Superior, the most northern of the lakes, was at 95.3 percent coverage. It last was 100 percent ice covered in 1996.

Climate for Lake Erie is a bit milder, but the lake also is shallow compared to its counterparts, meaning it is more likely to freeze in winter. It was at 95.9 percent, on its way to the full coverage that also occurred in 1973, 1978, 1979, and 1996.

By contrast, coverage of Lake Ontario was just 32 percent. One reason for that, scientists theorize, is that the lake doesn’t freeze as easily as the rest because it has a greater capacity for “heat storage.” In other words, it is deep, like Superior, but has far less surface area, where the heat is lost. Also, moving water from Niagara Falls helps keep ice from forming.