Diel vertical migration of Sagitta setosa as inferred acoustically in the Black Sea

Mutlu, E
Swimming trajectories of chaetognaths Sagitta setosa Muller in the Black Sea were studied using an echosounder operating at 120 and 200 kHz and an acoustic Doppler current profiler (ADCP) operating at 150 kHz. S. setosa were acoustically discriminated with respect to vertical migration and swimming speed, according to dissolved oxygen (DO) concentration and the timing of migrations. S. setosa formed a concentration layer thicker than Calanus euxinus did (1-3 m). The migration was completed in about 2.5-4 h, upward migration starting before C. euxinus and downward migration after C. euxinus. Adult Sagitta swam fast only in the well-oxygenated layer (subsurface maximum DO). The DO was found to be a significant (p < 0.05) variable by partial correlation between the speed and hydrographical parameters. This feature constituted an oxygen-dependent influence on S. setosa's vertical swimming and distinguished S. setosa from C. euxinus. Chaetognaths migrated daily between the nearsurface and the oxycline or the suboxic zone (OMZ, see Fig. 3b for the layers characterized by DO). Whether the deepest depth limit of migration was the oxycline or the OMZ depended on the relative abundance of adult and immature (young) individuals in the concentration layer. In July and September, individuals belonging to a new generation did not migrate but stayed in subsurface water day and night.


Patterns of dark respiration in aquatic systems
Mantikci, Mustafa; Staehr, Peter A.; Hansen, Jorgen L. S.; Markager, Stiig (CSIRO Publishing, 2020-01-01)
We used continuous measurements of dissolved oxygen (DO) in dark bottles to characterise patterns of the dark respiration rate (R-dark) for three marine phytoplankton monocultures and in natural-water samples from two marine coastal systems. Furthermore, patterns of ecosystem community respiration rate were determined from open-water changes in DO in a fjord and in a lake. We considered two models of R-dark to describe temporal changes in DO: constant R-dark and decreasing R-dark; increasing R-dark. In addi...
A comparison of the contribution of zooplankton and nekton taxa to the near-surface acoustic structure of three Turkish seas
Mutlu, E (Wiley, 2005-03-01)
The bioacoustics of upper waters of the Black Sea, the Sea of Marmara, and the Mediterranean Sea were studied in October 1999 with an echosounder with 120 and 200 kHz dual-beam transducers. Net tows were taken to ground-truth the acoustic volume backscattering. A forward solution was applied to determine significant scatterers of the three seas with regard to detection limits of the frequencies and background noise measured in each sea. The noise was 4 dB higher in the Sea of Marmara than in the other two s...
Diurnal gut pigment rhythm and metabolic rate of Calanus euxinus in the Black Sea
Besiktepe, S; Svetlichny, L; Yuneva, T; Romanova, Z; Shulman, G (Springer Science and Business Media LLC, 2005-04-01)
The vertical distribution, diel gut pigment content and oxygen consumption of Calanus euxinus were studied in April and September 1995 in the Black Sea. Gut pigment content of C. euxinus females was associated with diel vertical migration of the individuals, and it varied with depth and time. Highest gut pigment content was observed during the nighttime, when females were in the chlorophyll a (chl a) rich surface waters, but significant feeding also occurred in the deep layer. Gut pigment content throughout...
Molecular approach to the chemical characterization of fish-exuded kairomone: a Fourier transform infrared spectroscopic study
Akkaş, Sara Banu; Beklioğlu, Meryem (Springer Science and Business Media LLC, 2010-01-01)
Diel vertical migration (DVM) bioassay-guided Fourier transform infrared spectroscopy can be a prominent non-destructive and innovative approach for ecological studies. During the characterization of the nature of the fish-exuded kairomone, the peak area results from the spectroscopic analysis of the control, fish-conditioned (F) and temperature incubated fish-conditioned (IF) treatments of the DVM bioassays demonstrated that there was a strong correlation between the alterations of the amine N-H, amide II,...
Egg production and growth rates of Calanus euxinus (Copepoda) in the Black Sea
Besiktepe, S; Telli, M (Oxford University Press (OUP), 2004-05-01)
Egg production rates (EPRs) of Calanus euxinus were measured in the Black Sea during October 2000 and May 2001. EPRs were generally low, on average 1.7 eggs female(-1) day(-1) in October 2000 and 3.9 eggs female(-1) day(-1) in May 2001. The relationships between EPRs and gonad maturity, depth-integrated chlorophyll a (Chl a) and mean surface layer temperature were examined. The EPRs were not related to depth-integrated Chl a, but were negatively correlated with temperature. EPRs were strongly related to the...
Citation Formats
E. Mutlu, “Diel vertical migration of Sagitta setosa as inferred acoustically in the Black Sea,” MARINE BIOLOGY, pp. 573–584, 2006, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/63949.