Fish

No! After the dinosaurs died out, nearly 65 million years passed before people appeared on Earth. However, small mammals (including shrew-sized primates) were alive at the time of the dinosaurs. Many scientists who study dinosaurs (vertebrate...
Yes. Lamprey and hagfish are both jawless fishes. They are the only living members of the taxonomical class Agnatha (Greek for “no jaws”). 
No, salmon are not endangered world-wide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are much healthier than others. These healthy populations usually occupy protected habitats such as the Hanford Reach...
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...
Yes, sturgeon really are the largest of the freshwater fish. The beluga sturgeon in Russia is the largest freshwater fish in the world. The white sturgeon is the largest freshwater fish in North America. White sturgeon have been reported to reach lengths...
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...
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 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...