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Entries in invasive species (213)

Friday
Aug212015

Tennessee, Cumberland River Fisheries Threatened by Asian Carp

Most anglers know that Asian carp are overwhelming populations of native fish in portions of the Mississippi, Missouri, and Illinois Rivers. Likely they are aware that the invaders could have catastrophic consequences for the sport fishery if they migrate into the Great Lakes.

And almost certainly they have seen photos of silver carp leaping from the water, like the one above, as they are frightened by passing boats. This iconic shot was taken in 2007  by Nerissa McClelland of Illinois Department of Natural Resources from the chase boat as an electrofishing survey was conducted on the Illinois River, just upstream from Havana.

What most anglers do NOT know is that silver and bighead carp also threaten the Tennessee and Cumberland River systems , along with the world-class sport fisheries in their reservoirs. Most at risk right now are Kentucky and Barkley Lakes, but the invaders are moving steadily upriver from there.

In the October issue of B.A.S.S. Times, I'll have a detailed report on what's happening to these fisheries and what might be done to save them. Following is some insight regarding the problem from Ben Duncan , a commercial fisherman:

"I think it's too late to fully save the Mississippi and Ohio Rivers. The quantity of carp in both those rivers is unimaginable, although sustained fishing does help. If we don't start soon, the Tennessee and Cumberland Rivers will soon follow.

"Using the Cumberland River as an example, the numbers on the Barkley pool are large, while two pools up--- Old Hickory Lake --- catches, while becoming more frequent, are still at manageable levels.

" I have been on these lakes all my life, and spend more time on the water in a year than most people do in 10, and I can already see how native fish are changing their behaviors due to the invasion of carp. I think it's even influenced the crappie population and spawn on Kentucky Lake. Commercially, we catch way fewer fish in the bays than we did seven or eight years ago---  especially buffalo--- a fish that competes with Asians for food. Such large schools of carp decimate the food source so there's no reason to enter the bays. I have observed the same patterns in gizzard shad. 

"Currently, commercial harvest is the only defense. Kentucky and Barkley lakes are two of the most productive reservoirs in the country and it's concerning that Asian carp have made them so vulnerable. There are still several anglers unaware of the severity of the problem and most need to be educated on how tackling the problem is a collaborative effort among all stakeholders."

Friday
Aug072015

Florida Fishery Restored by Dedicated Volunteers

The way it used to be: Gator sunning in the muck at Lake Trafford. Photo by Naples Daily News

Those who doubt that hydrilla can destroy a fishery need look only to Florida’s Lake Trafford.  Nearly 40 years ago, the invasive plant covered its 1,500 acres, and efforts to control the plant with herbicides resulted in a buildup of muck that reached 6 feet deep in places. 

That organic debris smothered native plants and hard bottom, fed algal blooms, and led directly to several fish kills, culminating with a massive die-off in 1996.Less than 20 years later, however, Lake Trafford also is a testament to what anglers and other involved citizens can do to make a difference. The fishery once again is vibrant and healthy, as evidenced by three TrophyCatch bass (8 pounds or better) being caught there earlier this year.

“A number of dedicated people, past and present, put in a lot of effort and energy to help bring this fishery back,” said Jon Fury, deputy director of the Division of Freshwater Fisheries for the Florida Fish and Wildlife Conservation Commission (FWC). “Seeing a largemouth bass entered into TrophyCatch from this lake is very gratifying.”

That effort began with Annie Olesky, who started a campaign to raise money to remove the muck.  Sadly, the wife of Ski Olesky, owner of Lake Trafford Marina, died just before the multi-million-dollar project began in 2005. Financed by Friends of Lake Trafford, FWC, the South Florida Water Management District, and the Collier County Tourist Development Council, the project began with 6.4 million cubic yards of muck being dredged from the lake.

“The removal of the muck was a key step,” said FWC biologist Barron Moody. “It impacted the ability of fish to spawn. It also reduced nutrient loading and improved water clarity so sunlight can get to submerged vegetation.

Plantings of bulrush, pondweed, and other native plants followed, as did stocking of 500,000 largemouth fingerlings by FWC. But those recent TrophyCatch bass weren’t the result of those 2010 and 2011 stockings. They were a few of the hearty survivors.

“In our sampling, we’ve seen that the hatchery fish aren’t that large,” Moody said. “They’re more in the 2- to 3-pound range.”

Additionally, hydrilla remains in the lake, but FWC and the water district are hopeful that they can keep it under control this time.

“I am so very proud of the partnership built between our local community, Collier County, the FWC, and partner agencies,” said FWC Commissioner Liesa Priddy, “The grassroots efforts by the local community, businesses and the people of Collier County set in motion the process that brought us to this successful conclusion -- this celebrated catch.”

Thursday
Jul302015

Exotic Catfish Are in Our Waters Too

Asian carp are the exotic fish species that we hear the most about, but plenty of others are established in our waters as well, mostly because of an under-regulated exotic pet industry and irresponsible aquarium owners. Clinton Richardson recently caught this unusual catfish while fishing the lower Susquehanna River.  Biologists identified it as a hybrid catfish from the aquarium trade, a cross between a redtail catfish and a tiger shovelnose catfish. Both grow large in their native South America.

"Irresponsible aquarium owners continue to introduce exotic and at times invasive fish to our waterways when their pet fish become too large or they tire of them," noted the Maryland Department of Natural Resources. "The introduction of the northern snakehead is a perfect example."

The big question now is whether climate is too cold for such exotic catfish to establish breeding populations that far north, if they haven't already.

USGS photo

In Florida, meanwhile, the suckermouth armored catfish, also from South America, is firmly entrenched over much of the peninsula. And almost certainly it came from the aquarium trade as well, as it often is labeled a "plecostomus" or "algae eater."

The burrows that they make for spawning likely cause or exacerbate erosion on shorelines of canals and rivers, although no quantitative data is available on that. Additionally, they have been observed browsing on the algae that frequently grows on the backs of manatees.

"Manatee responses varied widely; some did not react visibly to attached catfish whereas others appeared agitated and attempted to dislodge the fish. The costs and/or benefits of this interaction to manatees remain unclear," said the U.S. Geological Survey.

Monday
Jul272015

Early Warning System Created for Harmful Algal Blooms

Lake Erie algal boom. Photo by Michigan Sea Grant

Four federal agencies have joined forces to create an early warning system for toxic and nuisance algal blooms (HABs) in the Great Lakes and other freshwater systems.

Harmful algal blooms have emerged as a significant public health and economic issue that requires extensive scientific investigation,” said Suzette Kimball, acting director of the U.S. Geological Survey (USGS).

USGS, U.S. Environmental Protection Agency, the National Aeronautics and Space Administration (NASA), and the National Oceanic and Atmospheric Administration (NOAA) will use satellites to gather color dates from freshwater bodies during scans of the Earth. They then will share the findings with state and local agencies so they can provide public health advisories when needed.

“In addition, the project will improve the understanding of the environmental causes and health effects of these cyanobacteria and phytoplankton blooms in the United States,” NOAA said in a press release.

NOAA added that these blooms are a global problem. “Cyanobacteria (blue-green alga)  is of particular concern because it produces toxins that can kill wildlife and domestic animals and cause illness in humans through exposure to contaminated freshwater and consumption of contaminated drinking water, fish, or shellfish,” it said.

HABs have been on the increase since the mid 1990s, according to Michigan Sea Grant College Program. In the Great Lakes, malfunctioning septic systems, products with phosphates (dishwater detergent) and nitrogen (lawn fertilizers), and urban and agricultural runoff likely have contributed.

“Some scientists also link the increase of harmful algal blooms to the invasion of zebra and quagga mussels in the Great Lakes and the ability of the mussels to filter feed,” Sea Grant said. “Essentially, they eat the good algae and phytoplankton but release organisms like blue-green algae back into the water intact.”

HABs annually cost the nation about $64 million because of loss of recreational usage, additional treatment for drinking water, and decline in waterfront property values. In August 2014, Toledo, Ohio, an algal bloom in Lake Erie forced Toledo, Ohio, officials to temporarily ban consumption of drinking water supplied to more than 400,000 residents.

The new collaborative network will build on previous NASA ocean satellite sensor technologies created to study microscopic algal communities in the ocean, which play a role in climate change, ocean ecology, and the movement of carbon dioxide between the atmosphere and ocean.

Wednesday
Jun242015

New Challenges Face America's Trout, Says TU

America’s native trout have declined dramatically over the last century thanks to a number of threats ranging from hatchery fish stocking to logging and mining to poorly designed roads and livestock grazing practices. Now a new suite of threats, from energy development to a changing climate, poses even greater challenges.   

According to a new Trout Unlimited report titled, “State of the Trout,” these threats are greater than ever, and they make for an uncertain future for coldwater fish if steps are not taken to protect and restore habitat, reconnect tributaries to mainstem rivers and keep native trout populations viable for the benefit of anglers and the country’s riparian ecosystems.

The report notes that, of the nation’s 28 unique species and subspecies of trout and char, three are already extinct. Of the remaining 25 species, 13 occupy less than 25 percent of their native ranges.

Trout across America are dealing with the cumulative effects of resource extraction, climate change and the introduction and persistence of non-native fish into native trout waters. But, according to the report, there is hope for trout and for those who fish for them all across the nation. The report lays out a roadmap for native trout recovery and persistence, but it will require a host of advocates playing vital protection and restoration roles for years to come.

“It’s daunting when you consider the scope of the threats facing coldwater fish in the United States,” said Chris Wood, TU’s president and CEO. “But if you step back and look at the work that TU and our partners are already doing all across the country, it’s encouraging to see progress and to know that, with help from volunteers, private industry, government agencies and elected officials, we can replicate that progress and keep trout in our waters.

“And that’s why this report isn’t just for anglers or for biologists,” Wood continued. “This is a report for all Americans, because trout require the cleanest and coldest water to survive—and we all need clean water.”

Like Wood, report author Jack Williams, TU’s senior scientist, believes all Americans have a stake in this report, and that it will require a collective effort to ensure a future for native trout in America.

“The reasons many populations of native trout are on the ropes is because of our growing human population and the increasing demand on water resources,” Williams said. “For eons, the great diversity of trout genetics and life histories coupled with their widespread distribution allowed them to thrive. The changes we’ve made to their habitat over time, just by pursuing our lifestyle, has had a huge impact on water quality, connectivity and trout habitat. We’ve also stocked non-native trout on top of native populations, to the point where even well-adapted native trout are overcome by repeated stockings.”

Williams notes that common-sense conservation measures in the years to come can help native trout recover. But, restoration needs to take place across entire watersheds and be sustained over decades.

For instance, in Maggie Creek in northwest Nevada, collaborative restoration has been underway since the late 1980s. TU’s work with ranchers, the Bureau of Land Management and mining companies have restored 2,000 acres of riparian habitat and today native Lahontan cutthroat trout have been completely restored in 23 miles of Maggie Creek and its tributaries.

In Maine, where TU and its partners helped negotiate the removal of two dams and construction of fish passage on a third, more than 1,000 miles of the Penobscot River has been reopened to Atlantic salmon, striped bass, herring and shad.

In the West, in states like Idaho and Colorado, sportsmen and women have mobilized and helped protect millions of acres of intact, functional habitat that is vital to trout and the waters in which they swim. Broad-scale restoration work on streams in the Driftless Area of the Midwest has translated into waters that once held only 200 fish per mile to holding 2,000 fish per mile.

TU’s public and private partners are key to the report’s findings. Without help from government, private entities and volunteers, trout truly do face an uncertain future.

"The health of America's trout is directly connected to the health of our nation's watersheds—watersheds that provide clean drinking water, drive economic growth and support recreational fishing opportunities for millions of people across the nation," said U.S. Fish and Wildlife Service Director Dan Ashe. "The ‘State of the Trout’ report provides a valuable overview of the health of these fisheries, helping Trout Unlimited, the Fish and Wildlife Service and our partners identify priority areas for conservation."