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Climate: Too warm for equatorial fish?


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

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Report highlights problems of unreported commercial fishing

Chinese fleet takes 12 times more fish than it reports


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


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

BPA shown to confuse fish mating behavior

A red shiner.

Hormone-mimicking chemical could result in inter-species breeding

By Summit Voice

SUMMIT COUNTY — Already pinpointed as a potential health risk to humans, the controversial chemical BPA has now been found to affect the mating choices of fish. potentially leading to inter-breeding of species.

BPA, used in the manufacture of plastic household products, is hormone-mimicking chemical now widely found in aquatic ecosystems across the U.S. The chemical has been banned from baby bottles and childrens’ cups in 11 states. Continue reading

Colorado: Some rivers, fish already on life support

Wildlife managers implement voluntary fishing closure on the Yampa

Some Colorado rivers and streams will take a hit from the drought this summer, but fishing should be fine at high elevation reservoirs like Clinton Gulch.

By Bob Berwyn

SUMMIT COUNTY — During what should be the peak of the runoff season, some of Colorado’s streams and river are already on life support, including the Yampa River in Steamboat Springs, where state officials have asked anglers to observe a voluntary fishing closure.

The closure will be in effect from the upstream boundary of the Chuck Lewis State Wildlife Area downstream through the city limits of Steamboat Springs, and anglers are asked to avoid this area.

Ron Velarde, regional manager for Colorado Parks and Wildlife, said the closure is voluntary for now and anglers are asked to avoid fishing there during the hottest part of the day, or preferably, to fish in other areas. If conditions worsen and several criteria established by regulation are met, a strict emergency closure enforced by law may become necessary. Continue reading


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