Do leech eggs on crabs harm humans? If you're eating snow crab, do Kanibiru hazard humans'  health? What if you accidentally taste or swallow them?
Along Sea of Japan, it’s snow crab time

Kanibiru, the eggs of a leech-like parasite which are sometimes attached to the crabs, are seen as an indicator of quality rather than a blemish. As the local sea bottom is muddy, there are few rocks to attach eggs to, leaving the crab shells as one the few available hard surfaces. Thus, authentic Sea of Japan crabs are more likely to have them. Additionally, a heavy accumulation may mean that months have passed since molting, indicating fuller meat.

A Connoisseur Speaks on Seasonal Seafood「A Taste of Winter Snow Crab」 : SHUN GATE

Select crab with kanibiru (deep sea fish leech) eggs
Hashidate crabs have kanibiru eggs on their shells. Yuya says, “It looks bad but the meat actually tastes better.”
Most crab legs are packed in ice after being caught. Most of the lice do not survive the freezing process. They definitely do not survive the cooking process and do not harm the meat. It is unclear if fresh, raw crab lice directly from the ocean cause issues.
http://portal.ncdenr.org/web/mf/crab-leeches