Old-Growth Fishes Become Scarce under Fishing

摘要: Researchers have long recognized the importance of ecological differences at species level in structuring natural communities yet until recently often overlooked influence intraspecific trait variation, which can profoundly alter community dynamics [1]. Human extraction living resources reduce variation by, for example, causing truncation age and size structure populations, where numbers older individuals decline far more with exploitation than younger individuals. Age negatively affect population stability, increasing variability biomass [2-6], reducing productivity [7-10] life-history diversity traits such as spatial temporal pattern reproduction migration [4, 11-16]. Here, we quantified extent 63 fished populations across five ocean regions, measured by how much proportions fish oldest groups declined over time. The proportion classes decreased significantly 79% to 97% (compared historical or unfished values, respectively), magnitude was greater 90% 32% 41% populations. pervasiveness intensity indicates that fishing is likely stability many marine communities. Our findings suggest emphasis should be given management measures impact on truncation, including no-take areas, slot limits prohibit all except a narrow range sizes, rotational harvesting.