The American Bullfrogs are a highly reproductive aquatic species that are native in central, eastern United States and Southeastern Canada. This species was first introduced to western America as a food source (frog legs!); since then it escaped aquaculture ponds and have spread widely. Bullfrogs lay up to 20,000 eggs...
Asian carps—fish in the Cyprinid family—have been part of our culture for centuries. We use them as ornamental aquarium fish (goldfish and koi) and food fish, and to help keep aquaculture ponds clean. However, when Asian carps escape into natural waterways, they can cause big problems for human health, the...
The Chinese mitten crab was first identified in the south San Francisco Bay in 1992 by commercial shrimp trawlers, and quickly spread to the Sacramento and San Joaquin Rivers. The Chinese mitten crab threatens ecosystems, earthen structures, and fisheries by preying on and competing with many species, including fish eggs,...
What ancient animal in modern times has a primitave spinal cord that may resemble the first vertebrates on earth, spends most of its life stuck to a boat or rock, produces an exoskeleton made of cellulose and is more associated with plants than animals? Tunicates are marine invertebrate filter feeders...
Crayfish are one of the most threatened groups of animals in the world. About 45 percent of North American crayfish species are considered to be at risk of extinction. However, a few crayfish species are among the world's most invasive freshwater organisms. Taking into consideration that invasive crayfish are the...
Hydrilla and Brazilian elodea are invasive aquatic plants that occupy freshwater habitats. While hydrilla is native to Asia, Africa, and eastern Australia, and Brazilian elodea is native to South America, both plants are invasive to North America. Because these plants are related and both have pointed green leaves that whorl...
Knotweeds are a group of closely related invasive plants from Asia. Knotweeds are very tall plants that can grow to over three meters with bamboo-like hollow stems and heart-shaped or lance-shaped leaves. They spread quickly and form tall, dense thickets. They dominate stream banks, sides of roads, gardens, and other...
New Zealand mudsnails are a highly invasive species of freshwater mollusk of the family Hydrobiidae, also known as spring snails. Their ability to clone themselves and maintain high reproductive rates allows them to rapidly spread throughout the western United States. Some estimates indicate that one female can clone and produce...
The nutria is a large, semi-aquatic rodent native to South America. Nutria were introduced to the United States for their fur. After a boom in nutria ranches during the 1930s, the animals escaped or were released from fur farms in the Pacific Northwest, Louisiana and other states, where theyare now...
The Red-Eared Slider, also called the red-eared terrapin, is an American breed of turtle widely spread across the USA, and is quickly becoming an invasive species in many parts of the world. It is also the most popular breed of pet turtle in the US and is widely kept as...
Colonies of millions of quagga and zebra mussels foul and clog pipes, water treatment plants, and dam turbines and give a competitive boost to toxic algae. It takes only one contaminated boat and the right conditions for zebra and quagga mussels to infest a new watershed; once they have been...