from suitable spawning locations. The abundance of prey also plays a large factor in finding a suitable habitat. Life cycle Lake sturgeon have a very long lifespan. Males typically live for 55 years and females can live for 80 to 150 years. They grow quickly during a lengthy juvenile stage. Early life Lake sturgeon eggs begin yellowed and are attached to a fatty ovarian mass. When the eggs are mature, they become olive green, grey or black. The eggs typically hatch after 8 to 14 days. Observations suggest lake sturgeon and other fish and invertebrates likely consume some fertilized eggs while on the spawning grounds. At hatching, the larvae are barely discernible and are about 10 mm long. The larvae soon become pelagic, remaining far from the surface and bed, and negatively phototactic, or attracted to darkness, while searching for rocky places to hide. About two weeks after hatching, they disperse downstream with the current for several miles until settling back down upon the river bottom. As juveniles, all definitive adult structures, except for gonads, form. They are thought to feed on benthic invertebrates like adults. It is thought that during late summer, yearlings gather in large schools in shallow river mouths and bays. The juveniles can be found in the same habitats as adults after a year. Reproduction Male lake sturgeon typically reach sexual maturity at 8 to 12 years, but may take up to 22 years. Females reach sexual maturity at 14 to 33 years, most often from 24 to 26 years of age. These sturgeon spawn on clean, gravel shoals and stream rapids, usually from April to June. They prefer to spawn in temperatures between 55 and 64 degrees Fahrenheit. Lake sturgeon reproduce by swimming around each other in circles and shaking violently; the male stops circling when he has released his fertilizer and the female then lays her eggs. Males spawn every 2 to 7 years while females spawn every 4 to 9 years. Only 10 to 20 percent of adult lake sturgeon are sexually active during a season Lake sturgeon are polygamous, maximizing genetic diversity. Conservation These fish were once killed as a nuisance by catch because they damaged fishing gear. When their meat and eggs became prized, commercial fishermen targeted them. Between 1879 and 1900, the Great Lakes commercial sturgeon fishery brought in an average of 4 million pounds (1800 metric tons) per year.