Modeling the impact of climate variability on Black Sea anchovy recruitment and production

Güraslan, Ceren
Fach Salihoğlu, Bettina Andrea
Oğuz, Temel
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 correlation of anchovy egg production and recruitment success in response to changes in temperature. Each decrease of 2 degrees C in summer mean temperatures resulted in a delay in the timing of egg production of between 12 and 19 days. Water temperatures in the spawning season had a greater influence than the number of available spawning females on the intensity of egg production. Anchovy recruitment was similarly influenced by temperature, with decreased temperatures resulting in a significant delay in the onset of peak recruitment during the fall by 21-38 days. Also, recruitment numbers in December decreased by about 20% with decreasing temperatures. The impact of temperature on production was slightly diminished by the impact of vertical mixing. The strong linkage of climate variability with anchovy spawning and recruitment has an important prediction potential for short-term anchovy stock estimations, which may serve fisheries management purposes.


Güraslan, Ceren; Fach Salihoğlu, Bettina; Department of Oceanography (2016-10-21)
Black Sea anchovy (Engraulis encrasicolus ponticus) undertake extensive (~1000km long) overwintering migration in autumn from northern spawning grounds to the overwintering areas located at the south-eastern coasts of the Black Sea. When arriving at the Anatolian coast, they support important fisheries in Turkey. Black Sea anchovy is known to experience stock variability quite frequently including stock collapses, which are believed to be closely linked with environmental conditions. Therefore, it is of imp...
Modeling the influence of hydrodynamic processes on anchovy distribution and connectivity in the black sea Karadeniz'deki hamsi dağılımı ve bölgeler arası bağlantısı üzerine hidrodinamik proseslerin etkisinin modellenmesi
Fach Salihoğlu, Bettina Andrea (2014-01-01)
Dispersal mechanisms of Black Sea anchovy larvae (Engraulis encrasicolus ponticus) across the Black Sea were studied with an individual based anchovy larvae model embedded in a Lagrangian model using surface currents calculated from daily dynamic height topography maps of altimeter data during a period of three years (2001-2003). Particles representing anchovy eggs were released at different sites during June to August and their movement was tracked over time. Drifters were advected for 36 days, representin...
Understanding the Impact of Environmental Variability on Anchovy Overwintering Migration in the Black Sea and its Implications for the Fishing Industry
Güraslan, Ceren; Fach Salihoğlu, Bettina Andrea; Oğuz, Temel (2017-01-01)
Black Sea anchovy (Engraulis encrasicolus) undertake extensive overwintering migrations every fall from nursery grounds to warmer overwintering areas located on the south-eastern coast of the Black Sea. During migration and particularly upon arrival at the Anatolian coast, they support an important fishery and valuable source of income for the regional community. Black Sea anchovy have undergone significant stock fluctuations partly related to climatic conditions, for example, migrating anchovy schools arri...
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...
Invasion dynamics of the alien ctenophore Mnemiopsis leidyi and its impact on anchovy collapse in the Black Sea
Oğuz, Temel; Fach Salihoğlu, Bettina Andrea; Salihoğlu, Barış (2008-12-01)
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 vuln...
Citation Formats
C. Güraslan, B. A. Fach Salihoğlu, and T. Oğuz, “Modeling the impact of climate variability on Black Sea anchovy recruitment and production,” FISHERIES OCEANOGRAPHY, pp. 436–457, 2014, Accessed: 00, 2020. [Online]. Available: