My mind's gones completely blank and I was wondering why the sharks were punished last year which resulted in John's punishment move to Tigers??

because...
as a joke the tigers 'kidnapped' annie(i think that was her name possibly...) after shed stayed on their island for one night in an island swap thing and then the sharks went over to get her back and stepped foot on tiger island on a day that wasn't the beach party day
therfore resulting in punishment

well thats what i remember anyway

just to let you know it wasn't annie they kidnapped it was anna!