MODELING THE CONNECTIVITY OF ANTARCTIC KRILL (EUPHAUSIA SUPERBA) IN THE LAZAREV SEA


Fach Salihoğlu B. A. , Cagdas B., Sadighrad E., Guess O., Hauck J., Timmermann R., ...More

5. Ulusal Deniz Bilimleri Konferansi 2022, Trabzon, Turkey, 1 - 03 June 2022, pp.216-217

  • Publication Type: Conference Paper / Summary Text
  • City: Trabzon
  • Country: Turkey
  • Page Numbers: pp.216-217
  • Middle East Technical University Affiliated: Yes

Abstract

The dispersal of pelagic larvae in marine environments is one mechanism of connecting marine populations across large distances and structuring their population success and persistence. It is mostly

the planktonic stages of marine species that are affected by such large-scale transport during the times when directional swimming is not yet developed. In the Southern Ocean, Antarctic krill is a key component of the marine food web playing a fundamental role in the transfer of energy between the lower and the upper trophic levels. Krill inhabits the Southern Ocean predominantly south of the Polar Front, with krill distribution concentrated in the southwest Atlantic sector, which includes the Lazarev Sea where krill biomass between 0.6 to 16.8 ind m-2 have been measured. These numbers point to large spatial and temporal variations in krill standing stock, which also surveys in several other regions such as the Scotia Sea have shown. The motivation of this study is therefore to investigate the possible connection of Lazarev Sea krill with other Southern Ocean krill populations via ocean currents and find the population(s) supplying input to the Lazarev Sea krill population. This is achieved by simulating Antarctic krill larval dispersal and connectivity via ocean currents with Lagrangian particle tracking simulations. The environmental conditions in the Lazarev Sea are simulated with a high-resolution, circumpolar hydrodynamic-ecosystem model (FESOM-REcoM2). Results indicate that this region does not support a single self-maintaining population, but represents a complex transition zone of krill with different origins, particularly from parts of the Weddell Sea and as far as the South Sandwich Islands. Krill located in the Lazarev Sea may reach as far as the Riiser-Larsen Sea within one year of transport time. High interannual variability in transport times and pathways may be one factor explaining the high variability of krill concentrations in the Lazarev Sea.