Striped bass in California

“Striped bass begin spawning in the spring when the water temperature reaches 60 degrees. Most spawning occurs between 61 and 69 degrees and the spawning period usually extends from April to mid-June. Stripers spawn in open fresh water where the current is moderate to swift. The Delta, especially the San Joaquin River between the Antioch Bridge and the mouth of Middle River, and other channels in this area, is an important spawning ground. Another important spawning area is the Sacramento River between Sacramento and Princeton. About one-half to two-thirds of the eggs are spawned in the Sacramento River and the remainder in the Delta. Female striped bass usually spawn for the first time in their fourth or fifth year, when they are 21 to 25 inches long. Some males mature when they are 2 years old and only about 11 inches long. Most males are mature at age 3 and nearly all females at age 5.”

“Stripers are very prolific. A 5-pound female may spawn 180,000 eggs in one season and a 15-pound fish is capable of producing over a million eggs. This great reproductive potential and favorable environmental conditions allowed striped bass to establish a large population within a few years after their introduction in California. Striped bass often spawn in large schools. On one occasion, CDFW biologists observed a school of several thousand bass at the surface along the bank of the Sacramento River above Knights Landing. Small groups of three to six bass frequently segregated from this school and splashed and churned in the main current of the river in the act of spawning. At times, five or more groups of bass were observed spawning at once. Usually, a large female was accompanied by several smaller males. While the eggs are still in the female, they are only about 1/25 inch in diameter”