What is the term for the growth rings used to determine the age of fish?

The term "annuli" refers specifically to the growth rings found on the scales, otoliths (ear stones), or other hard structures of fish that are used to determine their age. Each annulus represents a period of growth, typically corresponding to one year of the fish's life.

The presence of annuli is significant in fish biology and ecology because it allows researchers and fisheries managers to estimate age, growth rates, and ultimately contribute to effective management strategies for fish populations. The interpretation of these growth rings can provide insights into the health and dynamics of fish populations, influencing conservation efforts and fishing regulations.

Other terms, such as "nuclei," "layers," and "growth bands," do not specifically relate to the age determination process in a standard way as annuli do. Nuclei generally refer to the center points of cells or structures rather than age indicators. Layers and growth bands can be used informally but lack the specific biological definition inherent to annuli, making them less precise in the context of determining fish age.