USGS study finds high prevalence of intersex bass in Northeastern U.S. wildlife refuges

Smallmouth bass illegally introduced to Colorado waters threaten native fish.

Bass in and near wildlife refuges in the Northeastern U.S. are gender-confused.

Are endocrine disrupting chemicals to blame?

Staff Report

US Geological Survey researchers say they’re not 100 percent sure if endocrine-disrupting chemicals are to blame, but they’ve found that a full 85  percent of male smallmouth bass and 27 percent of male largemouth bass tested in waters in or near 19 National Wildlife Refuges in the Northeast U.S. were intersex.

Intersex is when one sex develops characteristics of the opposite sex. It is tied to the exposure of fish to endocrine-disrupting chemicals that can affect the reproductive system and cause the development of characteristics of the opposite sex, such as immature eggs in the testes of male fish. Continue reading

Fish swimming toward poles as fast as they can to escape global warming

Study projects major shifts in species richness patterns

sdfg

A map from the new University of British Columbia study shows the current distribution of species richness based on data going back to the 1950s.

Staff Report

FRISCO — Many fish species are racing away from the equator and toward the poles to escape steadily warming ocean temperatures. In a worst-case scenario of unchecked greenhouse gas emissions, many fish will disappear from the tropics by 2050, moving poleward by as much as 26 kilometers per decade.

Under the best-case scenario, where the Earth warms by just 1 degree Celsius, fish would move 15 kilometres every decade, according to a new study by scientists with the University of British Columbia study that examined the impact of climate change on fish stocks. Continue reading

Climate: Too warm for equatorial fish?

ijo

Global warming threatens equatorial fish populations.

Many equatorial fish species already living close to their thermal limits

By Summit Voice

FRISCO — Global warming could put many equatorial species of fish at risk, according to scientists who studied six common species of fish living on coral reefs near the equator.

“Our studies found that one species of fish could not even survive in water just three degrees Celsius warmer than what it lives in now,” says the lead author of the study, Dr. Jodie Rummer from the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

Rummer said many species in this region only experience a very narrow range of temperatures over their entire lives, and so are likely adapted to perform best at those temperatures. This means climate change places equatorial marine species most at risk, as oceans are projected to warm by two to three degrees Celsius by the end of this century. Continue reading

Report highlights problems of unreported commercial fishing

Chinese fleet takes 12 times more fish than it reports

asdaf

A new analysis shows where China catches its fish.

By Summit Voice

SUMMIT COUNTY — Illegal fishing is a persistent problem, but it appears that China has elevated it to a new level, catching about 12 times more fish than it formally reports to the United Nation’s Food and Agriculture Organization, an international agency that keeps track of global fisheries catches.

Overall, Chinese fishing boats catch about US$11.5 billion worth of fish from beyond their country’s own waters each year according to a new study led by fisheries scientists at the University of British Columbia.

“China hasn’t been forthcoming about its fisheries catches,” said Dirk Zeller, a senior research fellow with UBC’s Sea Around Us Project and the study’s co-author. “While not reporting catches doesn’t necessarily mean the fishing is illegal … we simply don’t know for sure as this information just isn’t available,” Zeller said, explaining that there could be agreements between China and other countries that allow unreported fishing. Continue reading

Study focuses on aquatic habitat in cold-weather regions

sdfg

It is difficult to be a fish when the bottom of the river is covered with ice. Winter image from the river Orkla in Norway. Photo courtesy Knut Alfredsen.

Most existing models are geared toward ice-free periods

By Summit Voice

FRISCO — Norwegian and Swedish biologists have taken a closer look at how extreme winter conditions in streams and rivers in cold regions, with an eye toward climate change models that predict more frequent variations between freeze and thaw conditions.

“Today most models focus on the ice-free period … In order to be able to manage streams and rivers in a long-term sustainable manner, we need to pay attention to future changes in climate when we, for example, design restoration and conservation measures, the researchers wrote in a new paper published this month in the journal BioScience.

“The predictions made about what the winter climate will be like in the future say that there will be more back and forth between thaw and frost, entailing more unstable ice conditions, more rain, and flooding, and ultimately perhaps more challenges to the survival of fish in many waterways,” said Christer Nilsson, of Sweden’s Umeå University. Continue reading

Biodiversity: North America’s freshwater fish disappearing

The Colorado pikeminnow has been extirpated from Nevada. Photo courtesy Nevada Natural Heritage Program.

Modern era rate of extinction more than 800 times higher than background rate over geological time

By Summit Voice

SUMMIT COUNTY — Habitat loss and the spread of invasive species have led to an”alarming” increase in the rate of extinction among North American freshwater fish, according to a new study by U.S. Geological Survey researcher Noel M. Burkhead, who documented fish populations going back to the late 1800s.

The rate of extinctions increased noticeably after 1950, although it leveled off in the past decade. The number of extinct species has grown by 25 percent since 1989, Burkhead wrote in a study published in the September issue of  BioScience. Continue reading

Colorado: Bucket biologists endanger native fish

Southwestern Colorado trout fishery threatened by bass

Smallmouth bass illegally introduced to Colorado waters threaten native fish.

SUMMIT COUNTY — Bucket biologists are causing more headaches for Colorado wildlife managers by illegally stocking fish, including smallmouth bass at Miramonte Reservoir in San Miguel County.

Colorado Parks and Wildlife is now planning to eradicate smallmouth bass by using an organic pesticide to kill all the fish in the reservoir and then rebuild this renowned trout fishery that attracts anglers from throughout the West. The operation is tentatively scheduled to occur in late summer or fall of 2013.

Along with threatening trout in the reservoir, the smallmouth bass are also a potential threat to three native fish species: Roundtail chub, the bluehead sucker and the flannelmouth sucker

In the meantime, Parks and Wildlife is implementing an emergency order that removes all bag and possession limits on smallmouth bass at Miramonte Reservoir.

“Killing all the fish in the reservoir lake is something we wish we didn’t have to do, but we know we must,” said Renzo DelPiccolo, area wildlife manager in Montrose. “People who illegally move fish into lakes, ponds and rivers are not only committing a criminal act, they are endangering native species, stealing a resource and recreational opportunity from thousands of anglers and negatively impacting the local community.” Continue reading

Follow

Get every new post delivered to your Inbox.

Join 8,998 other followers