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.
Study projects major shifts in species richness patterns
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.
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 “Climate: Too warm for equatorial fish?”→
Chinese fleet takes 12 times more fish than it reports
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 “Report highlights problems of unreported commercial fishing”→
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.
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.
Southwestern Colorado trout fishery threatened by bass
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 “Colorado: Bucket biologists endanger native fish”→