Freshwater Drum - Life History

Life History

During the summer, freshwater drum move into warm, shallow water that is less than 10 metres (33 ft) deep. The freshwater drum then spawn during a six to seven-week period from June through July when the water reaches a temperature of about 65 degrees Fahrenheit (18 degrees Celsius). During the spawn, females release their eggs into the water column and males release their sperm. Fertilization is random. Males generally reach sexual maturity at four years, whereas females reach maturity at five or six years. Females from six to nine years old have a clutch size of 34,000 to 66,500 eggs and they spawn in open water giving no parental care to their larvae. The eggs then float to the top of the water column and hatch between two and four days. Due to the broadcasting of eggs in open water and lack of parental care, many eggs and larvae fall victim to predation Upon hatching, the prolarvae average 3.2 millimeters long. The post larval stage begins about 45 hours after hatching and a length of 4.4 millimeters is attained.

Females grow at a faster rate than the males and adult characteristics start to form at a length of 15 millimeters. Females continue to outgrow the male throughout their lives reaching a length of 12 to 30 inches (30 to 76 cm). Usually the freshwater drum weighs 2–10 pounds, but they can reach well over 36 pounds. Freshwater drum are long-lived and have attained maximum ages of 72 years old in Red Lakes, Minnesota and 32 years old in the Cahaba River, Alabama. Using sectioned otoliths from archaeological sites near Lake Winnebago, Wisconsin, freshwater drum have attained the age 74 years. Though they can reach a very old age, the average age of a freshwater drum is between 6 and 13 years.