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Entries in USGS (16)

Wednesday
Sep212016

More Intersex Bass Found--- This Time in Illinois

The more waters that scientists investigate, the more intersex bass they find. Latest discovery is in the Des Plaines River, about 125 miles downstream from here.

In dissecting 51 male largemouth bass, researchers from the Illinois Natural History Survey (INHS) found that 21 had grown oocytes, or female eggs, in their testicular tissue.

“Long-term surveys conducted by the INHS in this region have shown big increases in largemouth bass over the past 40 years since the implementation of the Clean Water Act,” said fisheries biologist Mark Fritts. “It's a dichotomy here because we're seeing a population that has increased dramatically, but we're also seeing this potential problem rising.”

But this part of the river is far from pollution free. Treated sewage from Chicago flows into this area from the Chicago sanitary and Ship Canal. In a 2016 water quality report, the Illinois Protection Agency found 12 out of the 14 segments of the river tested were impaired by contaminants such a fecal bacteria and toxic industrial chemicals.

Pollution seems to be the common thread in other discoveries of intersex bass, both from municipal sewage and agricultural runoff. Specifics are elusive, except for the belief that chemicals acting as "endocrine disruptors" are causing the mutations.  They distort functions that regulate hormones and the reproductive system.

"This is an emerging field of research. We're kind of on the tip of the iceberg," Fritts said. "There are still a lot more questions than answers."

Starting in 2003, scientists with the U.S. Geological Survey (USGS) found male smallmouth and largemouth bass with immature eggs in several areas of the Potomac River. Then they noted intersex smallmouth and white suckers at 16 sites in the Delaware, Ohio, and Susquehanna Rivers in Pennsylvania.  At one site near Hershey, Pa., 100 percent of male bass sampled had eggs.

Of these findings, USGS scientist Vicki Blazer said, "We keep seeing a correlation with the percent of agriculture in the watershed where we conduct a study."

Additionally, studies conducted from 1995 to 2004, revealed  intersex bass in the Apalachicola, Savannah, and Pee Dee River basins of the Southeast.

Just last year, meanwhile, two federal agencies found significant numbers of male bass were intersex in waters of or near National Wildlife Refuges in the Northeast. Eighty-five percent of male smallmouths and 27 percent of male largemouths tested positive, according to USGS and the U.S. Fish and Wildlife Service.

 

Sunday
Aug212016

Grass Carp Invasion Also Threatens Great Lakes Fisheries

Most don't know one carp from another. All are exotic.The photo above is a 30-pound-plus grass carp illegally stocked in a small lake.

Common carp have been in this country for so long (more than a century) that many think they are native. They are not. They were imported by the federal government. Rooting around on the bottom, they have destroyed and degraded many fisheries.

Fish farms in the South and Mid-South imported Asian carp (bighead and silver), and they escaped into rivers, spreading throughout much of the country. Through filter feeding, they gobble up forage needed by many native species, including juvenile sport species.

Grass carp were imported to eat problematic aquatic plants, including hydrilla and Eurasian watermilfoil, also exotic species. Often they were overstocked. Sometimes. they were stocked where they were not needed. Often they were stocked illegally. And they too have escaped and spread.

To add to the confusion, Canadian media and fisheries officials frequently refer to grass carp as Asian carp.

*    *    *    *

Although silver and bighead are the Asian carp of most concern these days for the Great Lakes and its tributaries,  disturbing discoveries have been made lately regarding a third--- the grass carp.

First, a graduate student at the University of Toledo found eggs in the Sandusky River, which flows into Lake Erie. That confirms the existence of a reproducing population of this fast-growing species, which doesn't compete with native fish, but does obliterate beneficial aquatic vegetation.

Additionally, Canadian commercial fishermen recently netted a grass carp weighing more than 60 pounds from the St. Lawrence River, far above Lake Ontario.

Anthony Ricciardi, a biology professor at McGill University, doesn't think that the river has a reproducing population, but suspects that others are in the St. Lawrence as well.

"We actually thought the Asian carp was confined," added Quebec biologist Michel Legault. "But we know that in recent years the grass carp has been found in a small section of Lake Erie. And last summer, nine grass carp were caught in the Toronto area. This is not good news."

On the Sandusky, meanwhile Toledo researchers intend to learn more about the grass carp spawning there, in hopes of finding a way to minimize it.

"Given the similarities in reproductive strategies, this ongoing research on grass carp spawning may help us minimize the risk of bighead carp and silver carp from establishing a foothold in the Great Lakes, said Patrick Kocovsky, a fisheries biologist with the U.S. Geological Survey. "What we learn here also might apply to potential control strategies in tributaries to the Mississippi River.

Today, most grass carp used to control invasive aquatic plants are triploid, meaning they can't reproduce. But fertile grass carp are believed to have first escaped from  an aquaculture facility in Arkansas back in the 1960s. They since have migrated throughout the Mississippi River drainage, as well as spread through authorized, illegal, and accidental introductions to 45 of the 50 states.

Tuesday
May242016

Islands, Other Habitat Created in Mississippi River's Pool 9

Armored with rocks to prevent erosion, nearly 100 acres of new islands will provide prime habitat for smallmouth bass when an $11.8 million restoration project on Pool 9 of the Mississippi River is completed in 2018.

Additionally, dredged areas that provided fill for the islands will offer valuable overwintering areas at least 8 feet deep for fish.

"This will be great for fish, waterfowl, shorebirds, and the people who enjoy them," said Karen Osterkamp, a fisheries biologist with the Iowa Department of Natural Resources, as seasonal work resumed recently on this portion of the river that separates northeastern Iowa from Wisconsin.

The ambitious rehabilitation was planned cooperatively by the U.S. Fish and Wildlife Service, U.S. Geological Survey and the Departments of Natural Resources in both Iowa and Wisconsin, with funding through the Army Corps of Engineers' Upper Mississippi River Restoration/Environmental Management Program.

Since Lock and Dam No. 9 was built in 1937, channelization has resulted in the loss of many natural islands and flood plain forests, reducing habitat for both fish and migratory birds. Seven islands and three emergent wetlands are being constructed in the 2,200-acre Harpers Slough backwater  between river miles 650 and 653 at the lower end of the pool to help restore the ecological balance.

"One of the main goals is to maintain habitat for  tundra swans and canvasback ducks that stop on Pool 9 during their migrations," said Mike Griffin, the Iowa's Mississippi River wildlife biologist.

He expects the new wetlands to bear large crops of arrowhead plants, whose underwater tubers, known as duck potatoes, are a preferred food for the thousands of tundra swans that visit the pool each year.

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.

Thursday
Apr162015

Human Drugs Harming Fish Fertility

Prescription drugs intended for humans are affecting our fisheries in frightening ways. That's because they or their residues are flushed down toilets and into our waterways. Birth control pills are among the most concerning because they affect fertility in bass and other species.

For example, a recent study by the U.S. Geological Survey found that fish exposed to a synthetic hormone called 17a-ethinylestradiol, or EE2, produced offspring that struggled to fertilize eggs. The grandchildren of the originally exposed fish suffered a 30 percent decrease in their fertilization rate. The authors mulled the impact of what they discovered and decided it wasn't good.

"If those trends continued, the potential for declines in overall population numbers might be expected in future generations," said Ramji Bhandari, a University of Missouri assistant research professor and a visiting scientist at USGS. "These adverse outcomes, if shown in natural populations, could have negative impacts on fish inhabiting contaminated aquatic environments."

Read more here.

Additionally, check out this previous post at Activist Angler about minnows exhibiting bizarre behavior because of drugs.