Several hypotheses have been proposed to explain cyclic fluctuations in abundance of some small mammal populations. These hypotheses have been controversial, however, and there is no consensus among biologists as to why population cycles occur. In a demographically based model, we tested the potential influence of phase-specific changes in life history traits (age at maturity, fertility, juveni...

Previous western and central Pacific Ocean (WCPO) yellowfin stock assessments assume that the reproductive potential is proportion to the spawning stock biomass, with maturity at age the only explicitly reproduction-related factor taken into account. Recruitment to maturity for yellowfin is affected by a number of intrinsic factors, including size-related, age-related, and spatial changes in se...

The main aim of this research was to estimate the genetic and phenotypic parameters for productive and reproductive traits of Esfahan native chickens. Traits included body weights at hatch (BW1), 8 weeks of age (BW8), 12 weeks of age (BW12), and at sexual maturity (WSM)], age at sex maturity (ASM), egg number (EN), average egg weight (AEW) in the first 12 weeks of production, and egg production...