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Mate choice is common in most animals, but the issue has largely been ignored in regard to pelagic copepods—the most abundant zooplankton group in the oceans. Contemporary demographic models of copepods assume that all encounters lead to successful copulation and viable egg production. We revisit the subject of copepod mating biology in the framework of(More)
That sexually mature fish skip reproduction, especially in response to poor condition, has been documented in many species. We present results from an energy-allocation life history model that shed light on the underlying logic of skipped spawning, based on the Northeast Arctic stock of Atlantic cod (Gadus morhua). The model predicts that skipped spawning(More)
Industrial fishing has been identified as a cause for life history changes in many harvested stocks, mainly because of the intense fishing mortality and its size-selectivity. Because these changes are potentially evolutionary, we investigate evolutionarily stable life-histories and yield in an energy-allocation state-dependent model for Northeast Arctic cod(More)
Ecosystems are not closed, but receive resource subsidies from other ecosystems. Energy, material and organisms are moved between systems by physical vectors, but migrating animals also transport resources between systems. We report on large scale energy transport from ocean to coast by a migrating fish population, the Norwegian spring-spawning (NSS)(More)
The adaptive timing of diapause – a search for evolutionarily robust strategies in Calanus finmarchicus Ø. Fiksen Fiksen, Ø. 2000. The adaptive timing of diapause – a search for evolutionarily robust strategies in Calanus finmarchicus. In environments with strong and variable seasonal fluctuations, organisms are selected on the basis of their phenology,(More)
Growth and survival through the early larval phase probably limit the production potential of many commercially important fish stocks. Attempts to increase the production of these stocks by restocking of juveniles have generally failed. Here, we analyse how enhanced concentrations of phytoplankton and zooplankton affect the survival of fish larvae during(More)
In microbial competition theory, the Michaelis-Menten (MM) half-saturation coefficient is often considered to be a trait of an organism defining competitive strength in a trade-off conflict with maximum uptake rate. Theoretical studies have shown that a quadratic model characterizes the uptake rate, and that this model can be approximated by a MM model.(More)
When prey and predator are seasonal migrants, encounters depend on migration phenologies and environmental constraints on predation. Here we investigate the relative contribution of seasonality in irradiance and prey abundance in shaping the rapid seasonal body condition increase of a migrating predator searching visually for its prey: the Norwegian(More)
A central simplifying assumption in evolutionary behavioral ecology has been that optimal behavior is unaffected by genetic or proximate constraints. Observations and experiments show otherwise, so that attention to decision architecture and mechanisms is needed. In psychology, the proximate constraints on decision making and the processes from perception(More)
Studies on the relationship between the optimal phenotype and its environment have had limited focus on genotype-to-phenotype pathways and their evolutionary consequences. Here, we study how multi-layered trait architecture and its associated constraints prescribe diversity. Using an idealized model of the emotion system in fish, we find that trait(More)