Invasion dynamics of the alien ctenophore Mnemiopsis leidyi and its impact on anchovy collapse in the Black Sea

The mechanisms governing the unprecedented 1989-90 anchovy-Mnemiopsis shift event in the Black Sea were evaluated with a coupled model of bioenergetic-based anchovy population dynamics and lower trophic food web structure. Simulations showed that a combination of direct and density-dependent effects of overfishing, eutrophication-induced nutrient enrichment, climate-induced over-enrichment and temperature-controlled Mnemiopsis spring production were involved in the shift. Eutrophication made the system vulnerable to further enrichment through the change of regional climate to a severe winter regime during 1985-87. While Mnemiopsis was acclimating to its new environment, increasing nitrate flux into the euphotic layer enhanced the carrying capacity of the system, but a disproportionate Mnemiopsis biomass increase was delayed until spring temperature conditions returned to normal in 1988-89. Enhanced carrying capacity provided a competitive advantage of food consumption to Mnemiopsis compared with anchovy, and warm spring temperature conditions promoted their spring-summer production. Prevalent high fishery pressure and increasing impact of Mnemiopsis on the food web further induced the anchovy stock collapse. However, the shift event did not result in alternation of the system to a new totally Mnemiopsis-invaded quasi-stable regime. Instead, anchovy started recovering when the subsequent strong 1991-93 cooling regime limited the Mnemiopsis population growth. Our analysis indicated that the switch of a large marine ecosystem to a totally gelatinous invader-dominated state requires extremely strong environmental perturbations. More often, environmental disturbances create a suitable niche for an alien gelatinous invader to become a member of the food web structure, and to share food resources with the native small pelagic fish community.


Quantification of the Synergistic Effects of Eutrophication, Apex Predator Pressure, and Internal Processes on the Black Sea Ecosystem
Salihoğlu, Barış (2013-12-01)
In the present study, a model of the lower-trophic pelagic food web of the Black Sea is considered in order to provide a quantitative understanding of the marked changes in the food web structure in response to changing top-down and bottom-up control mechanisms due to eutrophication, overfishing, and climatic changes. The simulations consider three particular parameters controlling the changes in the ecosystem structure due to these stressors; (i) the magnitude of the nitrate flux into the euphotic layer fr...
Modeling the impact of climate variability on Black Sea anchovy recruitment and production
Güraslan, Ceren; Fach Salihoğlu, Bettina Andrea; Oğuz, Temel (2014-09-01)
The connection of climate variability with anchovy spawning and recruitment in the Black Sea in particular, and other ecosystems in general, was studied using a two-way coupled lower trophic level and anchovy bioenergetics model. Climate variability was represented by a 50-yr time series of daily temperature and vertical mixing rates with stochastic variations. Temperature was found to be the dominant factor influencing early life stages and hence population dynamics of Black Sea anchovy as marked by a high...
Regional peculiarities of community-wide trophic cascades in strongly degraded Black Sea food web
Oguz, Temel; Salihoğlu, Barış; Moncheva, Snejana; Abaza, Valeria (2012-04-01)
The community-wide trophic cascade due to collapsed fish stocks and population outburst of invasive predators after the early 1990s resulted in different pelagic and benthic food web structures in the Black Sea. The northeastern region assumed their most simplified forms characterized by increasing mesozooplankton and polychaete biomass. The ecological degradation is more severe in the northwestern part, whereas the southern basin maintains an anchovy fishery under relatively weak gelatinous predation.
Challenges in integrative approaches to modelling the marine ecosystems of the North Atlantic: Physics to fish and coasts to ocean
Holt, Jason; Allen, J. Icarus; Anderson, Thomas R.; Brewin, Robert; Butenschoen, Momme; Harle, James; Huse, Geir; Lehodey, Patrick; Lindemann, Christian; Memery, Laurent; Salihoğlu, Barış; Senina, Inna; Yool, Andrew (2014-12-01)
It has long been recognised that there are strong interactions and feedbacks between climate, upper ocean biogeochemistry and marine food webs, and also that food web structure and phytoplankton community distribution are important determinants of variability in carbon production and export from the euphotic zone. Numerical models provide a vital tool to explore these interactions, given their capability to investigate multiple connected components of the system and the sensitivity to multiple drivers, incl...
Microplastic consumption and physiological response in Acartia clausi and Centropages typicus: Possible roles of feeding mechanisms
Svetlichny, Leonid; Isinibilir, Melek; Mykitchak, Taras; Eryalcin, Kamil Mert; Turkeri, Ezgi E.; Yuksel, Esin; Kıdeyş, Ahmet Erkan (2021-03-01)
Multi-day experiments were carried out with two Marmara Sea calanoid copepod species: Acartia clausi and Centropages typicus, to assess the possible role of the type of feeding on the consumption of microplastics and its influence on the rate of energy metabolism of these species. In a mixture of microplastic beads (6 mu m diameter) and algae Rhodomonas salina (5-10 mu m size range) with equal concentrations of about 5000 cells/beads mL(-1) the ambush feeder A. clausi consumed almost 5 times less microplast...
Citation Formats
T. Oğuz, B. A. Fach Salihoğlu, and B. Salihoğlu, “Invasion dynamics of the alien ctenophore Mnemiopsis leidyi and its impact on anchovy collapse in the Black Sea,” JOURNAL OF PLANKTON RESEARCH, pp. 1385–1397, 2008, Accessed: 00, 2020. [Online]. Available: