4.—(1) For the purposes of article 3(1) the tagging of the carcass of a salmon is to be carried out by affixing a salmon tag to the carcass in accordance with this article.
(2) The salmon tag must be affixed by the following method—
(a)by inserting it through the mouth of the salmon to emerge from the gill opening; and
(b)by securing and locking the tag around the gill cover.
(3) The salmon tag must be affixed to the carcass of the salmon no later than the time when the salmon is brought to the shore or bank.