The mass of fish (males and females or females only) in the population that contribute to reproduction. Often conventionally -defined as the product of weight-at-age and the proportion -mature-at-age. Alternatively, it can be defined as the biomass of +defined as the product of weight at age and the proportion +mature at age. Alternatively, it can be defined as the biomass of all individuals at or above “age at 50 percent maturity” or “size -at 50 percent maturity.” or the total biomass of fish of reproductive -age during the breeding season of a stock. Most often used as a proxy -for measuring egg production, the spawning biomass depends on the -abundance of the various age classes composing the stock and their +at 50 percent maturity” or the total biomass of fish of reproductive +age during the breeding season of a population. Spawning biomass depends on the +abundance of the various age classes composing the population and their past exploitation pattern, rate of growth, fishing and natural mortality -rates, onset of sexual maturity, and environmental conditions.
+rates, onset of sexual maturity, and environmental conditions. Most often +used as a proxy for measuring egg production.