Here we investigated whether the decreasing annual productivity (i.e. larval abundances) of Baltic Sea herring over the last decade is linked to warmer springs exceeding the physiological optimum of early life stages. Linking physiological thermal tolerance and recruitment indexes from the field, we found that warming is at least partially responsible for the steady decline in recruitment.
We parameterized an individual-based model for Atlantic herring larvae with data on swimming activity, nutritional and somatic condition, and standard metabolic rate under contrasting feeding environments. Larvae survived longer in the model, when they downregulated their standard metabolic rate.
This study shows how the standard metabolic rate of temperate fish larvae varies with differences in body size, growth rate, and feeding environment over a wide range of temperatures. Metabolic flexibility is helpful for fish larvae to withstand changes in biotic or abiotic environmental conditions, and survive adverse conditions.
Swimming ability is crucial for larval fish survival. We measured growth, development and ontogenetic changes in critical swimming speed of Atlantic herring larvae at three temperatures, and found it to be negatively correlated to body length-at-age, suggesting a trade-off between growth rate and locomotor activity.
The stability of marine fish populations is, next to natural or fishing mortality, based on the annual recruitment of the young-of-the-year. The variability in the number of these recruited fish is determined by effects of several abiotic and biotic …
Climate change will reduce the salinity in the Baltic Sea to levels that marine fish species may not be able to tolerate. We acutely exposed Atlantic herring larvae from different Baltic Sea populations to low salinities, and modelled the survival threshold now, and for salinity projections at the end of the 21st century. Climate-driven freshening will make some Baltic habitats unsuitable for larvae.
We exposed Atlantic herring larvae to different microplankton to simulate the plankton phenology in spring, and measured growth, condition, digestive enzyme and feeding activity, and survival. Microplankton promoted external feeding on larger prey but was insufficient to alter life span and growth.