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Oysters can change their sex from male to female to male and so on throughout their lives.

Sockeye can mature at ages between two and six years old but in most systems, one age group (usually four-year-old fish) dominates, meaning most of the offspring produced in any one brood-year return to spawn four years later. This year of increased population significance creates a cyclic dominance which leads to spectacular returns to the Adams River every four. Although there are many ideas about why this occurs, nobody knows for sure.