Dataset: ZooSCAN Images OAPS

Location:  35 and 50 degrees North in the northwest Atlantic and northeast Pacific

Methodology: To obtain samples, a 1 m Multiple Opening/Closing Net and Environmental Sensing System  (MOCNESS; Wiebe et al., 1985) equipped with 150 m nets was deployed during the mid-day and mid-night on cruises carried out as described in  https://www.bco-dmo.org/dataset/3546 . Briefly, sampling was at consistent intervals including 1000-800, 800-600, 600-400, 400-200, 200-100, 100-50, 50-25, 25-0m at day/night stations from 35 to 50 N in the northwest Atlantic in 2011, and from 35 and 50N along CLIVAR line P17N  in 2012.

Upon retrieval, the catch from each of the eight discrete nets were divided into splits. One-half of a sample was preserved in 95% ethanol,  was preserved in 5% buffered formalin, and was used for live viewing and picking, and then preserved in 70% ethanol.

A representative subsample of the formalin-preserved zooplankton community from each net were imaged using a ZooSCAN ver. 3 at 4,800 dpi (following the methods in: Gorsky et al., 2010, Vandromme et al., 2012 as detailed in Maas et al. 2021). In order to better represent all size classes in the images, the original sample was divided into three size categories. All individuals larger than 2 cm were selected by eye and scanned separately from all the others. The remainder of the sample was sieved through a 1-mm mesh sieve, and both size fractions were individually scanned. From these smaller size fractions, at least 1500 particles were scanned after subsampling using a Motoda splitter (Motoda, 1959), requiring generation of two separate scans for both size classes. This resulted in a total of five images per net.

Image names

Image names include:
cruise#_mocnessID_net#_sizefraction_ and _a|b if a replicate and end in _1.tif

Multiple images of the same size fraction were sometimes taken to obtain a sufficient number of particles. These replicates are named a or b. If there is no replicate they don’t have a letter in the image name. An a and b scan were always done for size classes d2 and d3.  This was important because the split size is for the sum of a+b (e.g. if a is ¼ and b is ¼, the acq_sub_part will be 0.5).

Example of image names:

ae1830_m13_n4_d3_a_1.tif  [a replicate]
ae1830_m13_n4_d3_b_1.tif  [a replicate]
ae1830_m13_n5_d1_1.tif      [no replicate]

Related Datasets may contain the "object_id" (the particle/organism id) which is constructed the same way as the image name except it as an additional _# at the end.  This additional number in the object_id is added by the Zooprocess software (Hydroptic, 2016).
e.g.
object_id:       ae1614_m3_n1_d2_a_1_100
image_name: ae1614_m3_n1_d2_a_1.tif

Problem report: None