BIOLOGIYA MORYA, 2025, Vol. 51, No. 4, pp. 220-231 |
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Population Characteristics of the Copepod Calanus euxinus Hulsemann, 1991 off the Crimea Coast (Black Sea) Kovalevsky Institute of Biology of the Southern Seas, Russian Academy of Sciences, Sevastopol 299011, Russia E-mail: Abundance, biomass, and size-age structure of the population, as well as the reserve lipid content of copepodites V, males, and females of the cold-water copepod Calanus euxinus Hulsemann, 1991, were determined based on the analysis of the field material collected in October 2022 in the deep-sea and shelf areas of the Black Sea off the Crimean Peninsula. It was found that in October 2022, the average abundance and biomass values of C. euxinus (8600 ± 1200 ind./m2 and 6.5 ± 0.8 g/m2, respectively) in the open sea areas increased twice compared to 2019. In the shelf zone, the average abundance and biomass values of C. euxinus differed insignificantly between the fall seasons of 2022 and 2019. The increase in the proportion of older copepodites in the deep-sea areas in 2022 indicated an increase in the species’ generative potential, while the high relative abundance of the early age stages of C. euxinus in the coastal zone indicated active population reproduction. The accumulation of large amounts of the reserved lipids in oil sacs of the older stages of C. euxinus (up to 27% of the body volume) showed favorable trophic conditions for the species in the deep-sea areas with ongoing warming in the Black Sea region. Key words: Calanus euxinus, abundance, biomass, size-age structure, lipid reserves, Black Sea. |
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