Females brood their young during the late winter. Tiny black sea cucumbers are parasitized by the Colombian cucumber sucker snail, "Vitreolina columbiana""." These tiny snails attach themselves to "C. vegae" and suck the fluids out of them. While this species is numerous it is so small that there is no commercial fishery. Externally, "Cucumaria vegae" is all but identical to another species of sea cucumber, "Cucumaria pseudocurata". This latter species extends from the southern-most range of the tiny black sea cucumber in British Columbia to Southern California. Detailed examination of the bony plates in the skin, the ossicles, suggests a gradual change over the geographic range of the two species, rather than a sharp difference at the boundary between the two. Similarly, comparisons of mitochondrial DNA show only modest differences between the two species. It may be that "C. vegae" and "C. pseuocurata", are in fact the same species.