As Moonlighter said, the MBAA vociferously raised with EPA the potential confusion over the zone boundaries in this area as a result of the dynamics of this area and the traditional way that many people fish this area.
I'm a member of Moreton Mixed Amateur Fishing Club and we spent a lot time in the 80s and 90s fishing Kalinga from the shore with the fish right on the edge or indeed flooding over the edge into a foot or two of water on the run-up tide at night. A few people still did this right up until the marine park rezoning, but my opinion is that it became a bit impractical (marine park or no marine park) with the erosion that occurred.
More specifically with respect to your question, the boundary makes reference to following the mangrove line. The defintion of the mangrove line in the zoning plan is as follows:
mangrove line
, for a mangrove forest, means a line that—
(a) runs along the outer boundary of the forest; and
(b) at each point where there is a gap in the outer boundary
of the forest, runs along—
(i) if the gap is caused by a mouth of a river, creek or
stream—the line that joins 1 side of the river, creek
or stream to the other side by running in the
general trend of the outer boundary of the forest; or
(ii) if subparagraph (i) does not apply—
(A) if the gap is near the mainland—the
mainland at high water; or
(B) if the gap is near an island—the island at
high water.
Clear as Kalinga mud? What a nightmare.