laws regarding the use of spear guns are actuality VERY old and have not been updated so the fine for using one impropriety eg loading out of water ect are like $50 max but the se of them in certain areas is restricted and the laws regarding that sort of thing are very tough make sure you are not diving in some sort of nature reserve or basically anywhere close the the rotto shore line.
go to the 5 fathom bank if you want to get anything decent freediving