The Population Characteristics of the Copepod Calanus euxinus Hulsemann, 1991 off the Crimea Coast (Black Sea)
摘要
The abundance, biomass, and size–age structure of the population, as well as the reserve lipid content in copepodites V, males, and females of the cold-water copepod Calanus euxinus Hulsemann, 1991, were estimated based on 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 of C. euxinus (8600 ± 1200 ind./m2 and 6.5 ± 0.8 g/m2, respectively) in the open sea areas increased by two times compared to 2019. In the shelf zone, the average abundance and biomass of C. euxinus differed insignificantly between the autumn seasons of 2022 and 2019. The increase in the proportion of late copepodite stages in the deep-sea areas in 2022 indicated an enhancement of the generative potential of the species, while the high relative abundance of early copepodite stages of C. euxinus in the coastal zone indicated active reproduction in the population. The accumulation of large amounts of reserve lipids in oil sacs of the late copepodite stages of C. euxinus (up to 27% of the body volume) showed the favorable trophic conditions for the species in the deep-sea areas against the background of ongoing warming in the Black Sea region.