Life Cycle of the Striped Bass
In the Maritimes, striped bass are known to spawn in freshwater or brackish areas during springtime. Spawning activity is triggered when the water temperature rises above 10°C. Studies from the U.S. have found that males typically arrive at spawning grounds first, and females later. When large numbers of spawners are present, the event can take place for 3-4 weeks, and usually occurs near the water's surface at dusk.
Striped bass begin their life cycle as small eggs, roughly 1.3 mm in diameter when released from the female prior to fertilization. Within 12 hours of being laid the eggs grow and harden, reaching a diameter between 3.4 and 3.8 mm. A moderate current is required for egg survival, as it allows them to remain suspended in the water column throughout incubation.
Once hatched, the yolk-sack larvae is 2.0 to 3.7 mm in size. This larval stage can last from 35-50 days, and is dependent on food resources as well as water temperature. Therefore, the direction and activity of tides are very important to the fate of this larvae.
Metamorphosis is the process during which the striped bass leave the larval stage and grow toward adulthood. This begins when the striper reaches approximately 20 mm in size, and is now called a juvenile. At this point, striped bass are more sensitive to their environment than during earlier life stages, and can be greatly affected by changes in water temperature and salinity. The transition from juvenile to adult, including sexual maturiy, takes 3 years in males. Sexual maturity of females may not be reached until 4 to 6 years of age.
Striped bass are known to be highly fecund, and can spawn multiple times during their life. However, whether or not they spawn in a given year depends on water conditions providing a suitable environment for egg and larvae survival. Populations of striped bass in northern regions can experience selective mortality in young-of-the-year. For instance, if a juvenile has not reached 100 mm by fall it is unlikely to survive their first winter. If water conditions are favourable, the life span of a striped bass is roughly 30 years.