European lobstermen used twine or brass wire to secure lobster claws until the invention of commercial rubber bands. North American lobstermen 'plugged' the claws with wood or plastic pegs. Some lobstermen only plugged one claw, some plugged both, and some used both rubber bands and plugs. Lobsters have always had a high mortality rate, especially once they are put in captivity with unnaturally close proximity to other lobsters, which triggers cannibalism. Experiments in the 1960s revealed that securing lobster claws with rubber bands is far less likely to infect and kill lobsters with a blood disease, though the mortality rate is still high due to other sources of infection, hypoxia, environmental pollutants, habitat destruction, overfishing, and ghost fishing. The transition from mixed methods of claw deactivation to rubber-dominated fishing came in the 1980s.

For more on this, see:

Inshore Lobster Fishing (1972) by John T. Everett

The Lobster Gangs of Maine (2012) by James M. Acheson

https://old.reddit.com/r/geopolitics/comments/db39es/introduction_to_lobster_politics/

https://old.reddit.com/r/geopolitics/comments/dvj44y/lobster_politics_part_2/