MEPS 419:109-120 (2010)  -  doi:10.3354/meps08837

Vulnerability of copepod eggs in salinity and temperature gradients of the Marmara and Black Seas

Leonid Svetlichny1,*, Elena Hubareva1, Genuario Belmonte2, Melek Isinibilir3, Funda Ustun4, I. Noyan Yilmaz5, Benin Toklu-Alıclı6

1Institute of Biology of the Southern Seas, Sevastopol 99011, Crimea, Ukraine
2Marine Biology Station, University of the Salento, 73100 Lecce, Italy
3Faculty of Fisheries, Istanbul University, 34130 Laleli, Istanbul, Turkey
4Faculty of Fisheries, Sinop University, Sinop 57000, Turkey
5Institute of Marine Sciences and Management, Istanbul University, 34470 Vefa, Istanbul, Turkey
6Department of Biology, Faculty of Science, Istanbul University, 4118 Vezneciler, Istanbul, Turkey

ABSTRACT: Mass density, sinking speed and hatching success of eggs in Calanus euxinus, Acartia clausi and A. tonsa have been examined in response to salinity and temperature of the Marmara and Black Seas. Eggs of C. euxinus from the Marmara and Black Sea populations (mean mass density of 1.036 to 1.040 g cm–3) laid in brackish (18 to 22 psu) upper layers of the Marmara Sea could sink to high-saline (~38.5 psu) deep layers during embryonic development. Gradual salinity increase from 22 to 38.5 psu in laboratory experiments reduced egg hatching success in C. euxinus from the Marmara Sea from 97 ± 4 to 47 ± 11% (means ± SD) while all eggs of the Black Sea C. euxinus did not hatch. Mean mass density of eggs in A. tonsa and A. clausi amounted to 1.062 and 1.044 g cm–3, respectively. Eggs of A. tonsa with higher mass density and longer development time than those of A. clausi could descend to high salinity strata in the Marmara Sea, or to a cold intermediate layer in the Black Sea. On the contrary, sinking depth of eggs of A. clausi should not exceed 30 m both in the Black and Marmara Seas, as this increases predator pressure. Hatching success in A. tonsa eggs laid at 18 psu decreased from 77.7 ± 18.5% at 20°C to 46.7 ± 21.5% at 7°C, and reduced to 10.2 ± 4.7% at 7°C and 39 psu. Egg hatching success in A. clausi from the Black Sea did not depend upon temperature, whilst it decreased dramatically from 80 to 90% to 3.3 to 10% after salinity increase from 18 to 38 psu.


KEY WORDS: Calanus euxinus · Acartia clausi ·Acartia tonsa · Egg mass density · Hatching success · Salinity and temperature tolerance · Black Sea · Marmara Sea


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Cite this article as: Svetlichny L, Hubareva E, Belmonte G, Isinibilir M, Ustun F, Yilmaz IN, Toklu-Alıclı B (2010) Vulnerability of copepod eggs in salinity and temperature gradients of the Marmara and Black Seas. Mar Ecol Prog Ser 419:109-120

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