Øyvind Fiksen

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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)
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)
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)
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)
In environments with strong and variable seasonal fluctuations, organisms are selected on the basis of their phenology, such as the timing of diapause, reproduction, or assembling of storage products. A simulation model of the dynamic balance of various phenologies within a population facing density-dependence and varying annual, environmentally determined(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)
One of the most troubling aspects of ecosystem models is the use of rather arbitrary feeding and preference functions. The predictions of plankton functional type models have been shown to be highly sensitive to the choice of foraging model, particularly in multiple prey situations. Here we propose ecological mechanics and evolutionary logic as a solution(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)
Authors Bjørn Ådlandsvik • Joachim Bartsch • David Brickman Howard I. Browman • Karen Edwards • Øyvind Fiksen Alejandro Gallego • Albert J. Hermann • Sarah Hinckley Edward Houde • Martin Huret • Jean-Olivier Irisson Geneviève Lacroix • Jeffrey M. Leis • Paul McCloghrie Bernard A. Megrey • Thomas Miller • Johan van der Molen Christian Mullon • Elizabeth W.(More)