Regional peculiarities of community-wide trophic cascades in strongly degraded Black Sea food web

Oguz, Temel
Salihoğlu, Barış
Moncheva, Snejana
Abaza, Valeria
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.


Climatic warming and accompanying changes in the ecological regime of the Black Sea during 1990s
Oguz, T; Cokacar, T; Malanotte-Rizzoli, P; Ducklow, HW (2003-09-27)
[1] The Black Sea ecosystem is shown to experience abrupt shifts in its all trophic levels from primary producers to apex predators in 1995 - 1996. It arises as a manifestation of concurrent changes in its physical climate introduced by intensive warming of its surface waters as well as abrupt increases in the mean sea level and the net annual mean fresh water flux. The warming is evident in the annual-mean sea surface temperature ( SST) data by a continuous rise at a rate of similar to0.25 degreesC per yea...
Abrupt transitions of the top-down controlled Black Sea pelagic ecosystem during 1960-2000: Evidence for regime-shifts under strong fishery exploitation and nutrient enrichment modulated by climate-induced variations
Oguz, Temel; Gilbert, Denis (Elsevier BV, 2007-02-01)
Functioning of the Black Sea ecosystem has profoundly changed since the early 1970s under cumulative effects of excessive nutrient enrichment, strong cooling/warming, over-exploitation of pelagic fish stocks, and population outbreak of gelatinous carnivores. Applying a set of criteria to the long-term (1960-2000) ecological time-series data, the present study demonstrates that the Black Sea ecosystem was reorganised during this transition phase in different forms of top-down controlled food web structure th...
Chemical composition, respiration and feeding rates of the new alien ctenophore, Beroe ovata, in the Black Sea
Finenko, GA; Anninsky, BE; Romanova, ZA; Abolmasova, GI; Kıdeyş, Ahmet Erkan (2001-05-01)
Maximum daily rations of the ctenophore Beroe ovata Brugiere and predatory impacts on the Mnemiopsis leidyi A. Agassiz population were estimated via digestion time, prey biomass and predator and prey density in Sevastopol Bay and adjacent water regions. Digestion times ranged from 0.5 to 5.2 h and depended on the prey/predator weight ratio. Overall, the mean daily ration was 45% of B. ovata wet weight. Preliminary conclusions are given on the B. ovata population as an effective control of the M. leidyi popu...
NIERMANN, U; BINGEL, F; GORBAN, A; GORDINA, AD; Gücü, Ali Cemal; Kıdeyş, Ahmet Erkan; KONSULOV, A; RADU, G; SUBBOTIN, AA; ZAIKA, VE (1994-11-01)
Two international surveys of anchovy eggs and larvae were carried out in the Black Sea at the beginning of the spawning season in June 1991 and during the main spawning period in July 1992. Horizontal tows demonstrated that the bulk of anchovy eggs acid larvae were distributed in the upper 3-m layer, but in downwelling areas eggs and larvae were found down to 70 m depth. In contrast to earlier studies, vertical hauls obtained during the present investigation contained higher egg numbers in the southern and ...
Recent changes in the spawning grounds of Black Sea anchovy, Engraulis encrasicolus
Gücü, Ali Cemal; Ok, Meltem; Sakinan, Serdar (2016-01-01)
Towards the end of the 1980s, when the spawning grounds in the northwestern shelf (NWS) of the Black Sea were lingering with the effects of eutrophication and of an exotic invasive ctenophore, a series of basin-wide international ichthyoplankton surveys pointed out an increase in the anchovies spawning in the southern half of the Black Sea. Later, with the help of international conservation efforts, several key littoral ecosystem components within the anchovy's historical spawning grounds showed signs of re...
Citation Formats
T. Oguz, B. Salihoğlu, S. Moncheva, and V. Abaza, “Regional peculiarities of community-wide trophic cascades in strongly degraded Black Sea food web,” JOURNAL OF PLANKTON RESEARCH, pp. 338–343, 2012, Accessed: 00, 2020. [Online]. Available: