EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Transport Barriers and the Retention of Calanus finmarchicus on the Lofoten Shelf in Early Spring 

Huizi Dong1,2, Meng Zhou1, Ziyuan Hu3, Zhaoru Zhang1, Yisen Zhong1, Sünnje Basedow4, and Walker Smith1,5
Huizi Dong et al.
  • 1School of Oceanography, Shanghai Jiao Tong University, Shanghai, China (
  • 2Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA (
  • 3Jiaozhou Bay National Marine Ecosystem Research Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China (
  • 4Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway (
  • 5Virginia Institute of Marine Science, William & Mary, Gloucester Pt., VA, USA (

Large aggregations of the copepod Calanus finmarchicus occur each spring in the shelf-slope-oceanic regions off the Lofoten-Vesterålen Islands where productive fisheries have traditionally supported local and global economies. The retention and off-shelf transport of C. finmarchicus populations were studied by analyzing ocean color remote sensing and satellite altimetry data between 2010 and 2019 and employing a Lagrangian Coherent Structures (LCS) model. Results revealed the existence of a transport barrier reoccurring at the shelf break that retains C. finmarchicus on the shelf for 30-70 days in the spring when C. finmarchicus were seasonally ascending to the surface layer. The analysis of baroclinic and barotropic energy conversions indicated that the topographically steered Norwegian Atlantic Current (NwAC) is the primary mechanism in the formation of the transport barrier, which restricts exchanges of C. finmarchicus populations between shelf and oceanic waters. In the mid- or late April, an increase in baroclinicity leads to an increase in mesoscale eddies generated on the shelf break near Lofoten-Vesterålen Islands, breaking down transport barriers and causing off-shelf transport of C. finmarchicus. The transport barrier predictably reoccurs in early spring which supports the entrapment of C. finmarchicus in the shelf region.

How to cite: Dong, H., Zhou, M., Hu, Z., Zhang, Z., Zhong, Y., Basedow, S., and Smith, W.: Transport Barriers and the Retention of Calanus finmarchicus on the Lofoten Shelf in Early Spring , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6005,, 2022.