Donna M, Pica pica,aka sea lice is an almost microscopic organism, actually i think a verrrry tiny jelly fish that can get trapped between your suit and skin and sting you raising welts and causing severe itching, if you come up thru a pool of them from below you can get them all over your face and arms. they typically appear april may and can go into june. last year for some reason was an especially bad year starting in april and going thru june , for i was there the week of 27th april and got stung up. there is a product called safe sea, that is sold over the internet simply google those 2 words safe sea and it will hook you up with retailers...leasure pro sells it at abt' 10 bucks a bottle....john in denver