Of the various marine habitats, one of the (if not the) most daunting to quantify is the under-sampled bathypelagic zone (\u3e 1000 m depth), which at 60% of the ocean’s volume is the largest habitat on Earth. One project addressing this challenge is the Census of
Marine Zooplankton (CMarZ), whose goal is the assessment of biodiversity of animal plankton throughout the world’s oceans. The 2006 CMarZ cruise in the Western North Atlantic provided an unprecedented opportunity to sample bathypelagic micronekton using a large midwater trawl (10-m2 MOCNESS) outfitted with fine (0.335-mm) mesh netting. This netting allowed non-destructive sampling of the fragile fish fauna to 5000 m depth, thus facilitating accurate identification and at-sea DNA extraction and sequencing. A total of 3,965 fish specimens were collected from at least 127 species (84 genera, 42 families), many rarely caught, and four of which may be undescribed. Of note were male anglerfishes from five families, which are poorly known. Tissue was taken from all males to match with females, thus enabling the construction of a key for the most diverse bathypelagic fish group
