Understanding the Impact of Environmental Variability on Anchovy Overwintering Migration in the Black Sea and its Implications for the Fishing Industry

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2017-01-01

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Güraslan, Ceren
Fach Salihoğlu, Bettina Andrea
Oğuz, Temel

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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 arrived late or failed to arrive at the Anatolian coast when fall temperatures increased. It is therefore of importance to understand the conditions required for successful overwintering migration and explore different migration routes. This study invokes a Lagrangian modeling approach applied to satellite derived circulation and temperature data as a first attempt to model anchovy migration dynamics in the Black Sea. This modeling approach takes the influence of the physical environment into account, while the quality of overwintering grounds, adaptive, schooling, and homing behavior is neglected. The model is used to investigate the possible influence of interannual and seasonal variability of temperature and surface currents, as well as the influence of migration behavior on the success of anchovy overwintering migration for both the Black Sea and Azov Sea anchovy. The results of the present work show the possibility that overwintering anchovy fished along the Turkish Eastern Anatolian coast may not exclusively originate from the northwestern shelf, but mainly from the eastern Black Sea basin. Migration pathways are identified for both Black Sea and Azov Sea anchovy, which are of importance for the national fisheries efforts of riparian countries. The modeling results are in agreement with general patterns of anchovy migration given in the literature indicating that the physical environment may be a major factor in shaping general migration patterns. Simulation results are used to hypothesize about alternatives to previously determined migration routes and provide potential reasons that explain the inability of the Bulgarian anchovy fishery to recover. Results show that the intensity and timing of autumnal cooling, coupled with current strength, can be of significant importance in determining annual and seasonal variability of migration success. Considering the need for fisheries management to account for the variability in fishable overwintering anchovy stocks a modeling approach as developed in the current study may provide such a tool.

Subject Keywords

Black Sea, Anchovy (Engraulis encrasicolus), Overwintering migration, Climate variability, Common Fisheries Policy

URI

https://hdl.handle.net/11511/32460

Journal

FRONTIERS IN MARINE SCIENCE

DOI

https://doi.org/10.3389/fmars.2017.00275

Collections

Graduate School of Marine Sciences, Article

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MODELING THE IMPACT OF CLIMATE VARIABILITY ON ANCHOVY OVERWINTERING MIGRATION IN THE BLACK SEA 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...
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Citation Formats

C. Güraslan, B. A. Fach Salihoğlu, and T. Oğuz, “Understanding the Impact of Environmental Variability on Anchovy Overwintering Migration in the Black Sea and its Implications for the Fishing Industry,” FRONTIERS IN MARINE SCIENCE, pp. 0–0, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/32460.