For anyone who was doubting it:

Electric Shock Study Revises Thinking About Invertebrate Protection Status

https://uk.news.yahoo.com/crabs-feel-pain-electric-shock-010000630.html#ZKwvCz8

STRESSED SHORE CRABS

Electrical Shocks Cause A Physiological Stress Response In Invertebrates Previously Thought Incapable Of Feeling Pain. The Scientist, Karen Zusi, November 12, 2015 http://www.the-scientist.com//?articles.view/articleNo/44452/title/Stressed-Shore-Crabs/