Control mechanisms on the ctenophore Mnemiopsis population dynamics: A modeling study

A comprehensive understanding of the mechanisms that control the ctenophore Mnemiopsis blooms in the Black Sea is gained with a zero-dimensional population based model. The stage resolving model considers detailed mass and population growth dynamics of four stages of model-ctenophore. These stages include the different growth characteristics of egg, juvenile, transitional and adult stages. The dietary patterns of the different stages follow the observations given in the literature. The model is able to represent consistent development patterns, while reflecting the physiological complexity of a population of Mnemiopsis species. The model is used to analyze the influence of temperature and food variability on Mnemiopsis reproduction and outburst. Model results imply a strong temperature control on all stages of Mnemiopsis and that high growth rates at high temperatures can only be reached if food sources are not limited (i.e. 25 mg C m− 3 and 90 mg C m− 3 mesozooplankton and microplankton, respectively). A decrease of 5 °C can result in considerable decrease in biomass of all stages, whereas at a temperature of 25 °C a 40% decrease in food concentrations could result in termination of transfer between stages. Model results demonstrate the strong role of mesozooplankton in controlling the adult ctenophore biomass capable of reproduction and that different nutritional requirements of each stage can be critical for population growth. The high overall population growth rates may occur only when growth conditions are favorable for both larval and lobate stages. Current model allows the flexibility to assess the effect of changing temperature and food conditions on different ctenophore stages. Without including this structure in end-to-end models it is not possible to analyze the influence of ctenophores on different trophic levels of the ecosystem.

Research highlights
► A stage resolving model of four stages of model-ctenophore is developed.
► The effect of changing temperature and food conditions on different stages is assessed.
► How food conditions or temperatures regulate transition between stages is quantified.