Physiological individual-based modelling of larval Atlantic herring (Clupea harengus) foraging and growth: insights on climate-driven life-history scheduling

A physiological individual-based model for the foraging and growth of Atlantic herring (Clupea harengus) larvae was constructed, validated using laboratory and field data, tested for parameter sensitivity, and used to examine climate-driven constraints on life-history scheduling. Model scenarios examined how natural (phenological and magnitude) changes in key environmental factors (temperature, prey, and photoperiod/daylength) affected the estimates of survival and growth of spring- and autumn-spawned larvae. The most suitable hatching seasons agreed well with the periods of larval abundance in Northeast Atlantic waters. Modelled survival is unlikely in June, July, and November. Mean annual temperature, prey concentration, and composition significantly influenced larval growth of both autumn and spring spawners. The model suggested that climate-driven changes in bottom-up factors will affect spring- and autumn-spawned larvae in different ways. It is unlikely that autumn-spawning herring will be able to avoid unfavourable conditions by delaying their spawning time or by utilizing more northern spawning grounds because of limitations in daylength to larval growth and survival. Conversely, earlier spawning in spring, or later, midsummer spawning will be tightly constrained by match mismatch dynamics between larvae and zooplankton production.