Mesozooplankton abundance, distribution and composition in the northern Baffin Bay: ArcticNet 2005-2018

Two samplers fitted with 200 µm to 500 µm mesh nets were used for zooplankton collection on the 2005 to 2011 and 2013 to 2018 ArcticNet's oceanographic missions onboard the NGCC Amundsen. One was a metallic structure with 4 nets of 1 m2 mouth aperture (2x2 multiple net sampler) for water column integrated sampling. For the years 2013 to 2018, one of the nets was replaced by a LOKI (Lightframe On-sight Keyspecies Investigation) imaging system. The other sampler was a 0.5 m2 mouth aperture multinet Hydrobios for stratified sampling into nine layers (selected stations only). Samplers were hauled vertically from 10 m above the sea bottom to the surface. Filtered volume was estimated by flowmeters mounted at the mouth of each net. The Hydrobios has an integrated flowmeter providing filtered volumes for each of its nine nets. Samples were preserved in a 10% buffered formalin seawater solution. Zooplankton samples were sieved through 1000 µm and 200 µm sieves for analysis. The two size fractions were separately resuspended in water and for each of them, all the organisms in a known aliquot containing approximately 300 copepods were counted and identified to the lowest possible taxonomical level, as well as developmental stages in the case of copepods. The dataset is formatted as a station-by-species matrix with each row corresponding to a specific station and date, each column to a species, and each cell containing the integrated abundance (ind. m⁻²).