That’s it. The American blockade was two-pronged: first with submarines interdicting resupply very effectively, and secondly with air and naval forces cutting off any island the Americans were going to invade. What supplies did get through undoubtedly consisted of mostly ammunition and key military must-haves.
Guadalcanal and many of the southwestern islands were steaming jungles, fetid and crawling with vermin. Iwo and the northern islands were often mostly volcanic pumice – it must have been like lying in road grit or worse 24 hours a day. Uniforms were probably shredded very quickly.