Streams

No. Although sturgeon and catfish can be found in the same habitats and they both have barbels (whiskerlike growths extending from the jaw), they are not closely related. Sturgeon are much more primitive than catfish. There are some catfish sold for...
Asian carp of all types have white, firm, mild flesh, which is excellent table fare, but all Asian carp also have intramuscular bones in the filets that many people find undesirable. Asian carp feed low on the food web, are fast growing, are low in fat...
Many studies show that bighead and silver carp substantially change ecosystems where they have been introduced. Studies around the world, including a USGS study in the Missouri River, found that zooplankton populations are dramatically reduced when Asian...
You can view a national map of hardness in surface water at water hardness map. Hardness data (reflecting mostly calcium, plus a little magnesium) for individual drinking-water suppliers can be found at this link EPA Office of Ground Water and Drinking...
Yes, it is not unusual for salt marshes to experience dieback in small patches in some years. However, these areas are usually less than an acre or so in size and generally regenerate the next year or over the next several years. Smooth cordgrass marshes...
An exponential increase in the population numbers of bighead and silver carp began in the mid-90s and continued through the mid-2000s in parts of the Mississippi and Illinois rivers. The Illinois Natural History Survey has estimated that a population of...
Both bighead and silver carp become fairly large; records of both species approach 100 pounds, but silver carp over 20 pounds and bighead carp over 30 pounds are uncommon. The North American record for bighead carp is a 106-pound fish from Missouri. Both...
The salinity of Great Salt Lake is measured by taking specific gravity and temperature measurements and comparing them to standardized values reported in a table. Specific gravity is measured in the field by testing a water sample with a device very...
A basic introduction to natural filtering of water can be found on-line at the USGS 'Water Science for Schools' website. The address for the site's ground-water-quality page is:Groundwater QualityNatural filtering is a big topic. Some filtering takes...
The USGS Grand Canyon Monitoring and Research Center in Flagstaff, Arizona, conducts at least eight trips each year to study endangered fish populations. The USGS is especially interested in the Humpback Chub, but we are interested in all of the fish in...