Maximizing lifetime egg production in a Wadden Sea population of the tellinid bivalve Macoma balthica: a trade-off between immediate and future reproductive outputs

摘要: The number of eggs produced in the annual spawning season by an adult female Macoma balthica (L.) Wadden Sea origin increases a non-linear manner with increasing shell length and body weight. It depends primarily on weight-at-length immediately before spawning. Lean individuals low body-mass index (BMI) 5.6 mg cm -3 or less spawn no eggs. Gamete output to about one-third soft-body weight (in order 100 000 eggs) at maximal BMIs observed (~15 ). Long-term monitoring (>20 yr) densities M. balth- ica population revealed that survival next year declined from 65% higher-than-average values BMI (>8 ) 30% lowest (5 6 Annual growth was also significantly lower years starting value. Because lowers thus BMI, is bound reduce subsequent rates body-weight increments. Thus, trade-off situation exists between immediate future outputs. consequences for total lifetime egg production vari- ous levels gamete first (at age 2 were estimated model calculations, wide range weights standard length. results realistically pre- dict can be achieved only if refrain below certain threshold value (viz. ~6 , which close their actual (again what actually happens). concluded populations apply strategy adapted local conditions.