In fisheries, recruitment refers to the number of fish surviving to enter a fishery. These fish have to pass through a number of life history stages (e.g., egg, larva, juvenile, etc.) before becoming vulnerable to fishing gear.
Understanding recruitment dynamics is a very complex process – dependent upon the spawning stock biomass and environmental factors. In some species, recruitment is density dependent; in many of these cases, a larger number of spawners will produce fewer recruits per individual because of competition between larval fish, cannibalism by adults, and other factors. In many species, 99% of mortality occurs at the egg stage. This is just one of the many things that make it difficult to forecast population assessments for fish species.