#Zebra mussels on fish skin#

Zebra mussels have no heads, and no eyes. Even if there are many close together, they do not seem to have any interaction with each other, except for reproduction. When they are abundant, they often completely cover any exposed rock or other surface. Once they attach, they do not move again. Zebra mussel larvae drift in the water, feeding and growing and then settle down on to a hard surface. The only parental investment is in the production of eggs and sperm. Average age at sexual or reproductive maturity (male) 1 years.Average age at sexual or reproductive maturity (female) 1 years.Breeding season Zebra mussels spawn when the water they live in is warm enough, usually starting in spring or summer.gonochoric/gonochoristic/dioecious (sexes separate).Zebra mussels are mature and able to reproduce when they are 8-9 mm long, usually after about one year of growth. Each can release as many as 1 million eggs each year. Females grow and release eggs in batches of up to 40,000, up to four times during the breeding season, which lasts as long as the water stays warm enough. Females release eggs into the water, and males release sperm, and fertilization occurs after they are released. In habitats where they water stays warm year round, they may reproduce continuously. ( Nalepa and Schloesser, 1993)Īdult zebra mussels start to reproduce in the spring, when water temperatures rise to about 12☌. Then it metamorphoses into the adult stage. It uses its foot to move slowly, and when it finds a suitable spot, glue itself to the surface, where it will stay for the rest of its life. The postveliger continues to grow, and after about a month, it settles onto a hard surface. It grows, and when it develops several internal organs (including a muscular foot), and peak (called an umbo) at the hinge of its shell, it is in the next stage, the postveliger. It can swim upward (but not strong enough to swim against a current), and has only a tiny start of a shell. About 3-5 days after fertilization, a tiny larva that emerges from the egg. The speed of development depends on temperature - warmer mussels grow faster. There are three stages in the life of a zebra mussel. Range length 2 (high) cm 0.79 (high) in.This helps them swim, and also draws food particles in for them to eat.

#Zebra mussels on fish skin#

Zebra mussel veligers have a tiny shell, and a curved sheet of skin called a velum, that is covered with tiny hairs that beat in the water. Veliger larvae are small enough that they can easily drift in the water, only about 100 micrometers long (0.1 mm) in diameter. This stage in molluscs is called a veliger. Zebra mussels have a free-swimming larval stage. Their body temperature as the temperature of their environment changes. Zebra mussels are ectothermic and heterothermic. In life they attach to substrate with a glue they secrete that forms fibers called byssal threads. The ventral side of the mussel is flattened, so much so that the mussel shell will stand on a flat surface.

Range depth 1 to 60 m 3.28 to 196.85 ftĪdult zebra mussels have a pair of roughly triangular shells connected by an elastic hinge, the outside of the shells are usually brown with stripes that give the species its common name in English, but patterns and the darkness of color varies.

Above that they slow down and again, and start to die at 30☌. They stop growing at about 3☌, and increase their growth and feeding rates as they warm to 20-25☌. They can live deeper however, and have been collected at least as deep as 60 m. Consequently most mussels live below ice levels, and the most dense populations are usually found between 2 and 12 meters in depth.

This species can survive exposure to temperatures as low as -10☌ for a few minutes, and warmer sub-freezing temperatures for hours or days. They do not thrive in pH lower than 6.8, and grow fastest in pH 7.4-8.4. They need at least moderate concentrations of calcium to grow their shells (approximately 25 mg calcium2+/liter) but can survive for some time in lower concentrations. Zebra mussels live in still or slow-moving freshwater, and attach themselves to any hard surface under water, natural or man-made, including rocks, submerged wood, boat hulls, buoys, docks, and water intake pipes. ( Nalepa and Schloesser, 1993 Neumann and Jenner, 1992 U.S. They now occur in the Great Lakes basin, most of the Mississippi River drainage, the Hudson River and many other eastern North American rivers. In the late 20th century they were accidentally brought to North America, probably in ballast water of large ships. Shipping and canal construction in the 19th century allowed them to spread west into most European rivers and lakes. Zebra mussels were originally found in the drainage basins of the Black and Caspian Seas, including the Danube, Dniester, Volga, and Ural Rivers.