The individual animals of a particular species (especially a fish) that were born in any one year.
- ‘The distribution of carapace length in each year class was divided into quartiles.’
- ‘WAPLES 1990 developed a statistical method for this situation that can be applied to Pacific salmon populations that have an unusual life history of semelparity with overlapping year classes.’
- ‘They refused to slow down because they had seen lots of little fish coming in - a good year class.’
- ‘Similar double asymptotic growth trajectories have been observed in other fish populations and have also been correlated with strong year classes of YOY perch.’
- ‘The temporal pattern reflects a winter diapause in the final instar larva that allows the majority of a year class to respond synchronously to rising temperatures in spring, and requires two years or more to complete a generation.’
- ‘Thus embryo diameter may be a factor in recruitment success of that year class.’
- ‘The resulting variation in reproductive output will lead to differences in population fecundity and the potential strength of a year class.’