Unknown Sea Cucumber 2 (Paelopatides sp.) or (Benthodytes sp.)
Sea cucumbers of Paelopatides species can be confused with species of Benthodytes, and species identification requires specimen examination. The holothurian assumes a vertical posture for swimming and can sustain active swimming for more than 20 minutes. This sea cucumber was found swimming at the Slope Base site (~2900 m).
References:
ccfzatlas.com/wiki/index.php?title=Paelopatides
agris.fao.org/agris-search/search.do?recordID=AV20120137251