There is a footbridge on the New South Wales south coast that crosses at the mouth of Lake Mummuga, near the sleepy village of Dalmeny.

On the other side of the bridge, and a short walk north, is Brou beach where one of the most head-scratching decisions in Australian marine conservation management has just been made.

Shortly before Christmas the NSW government announced the end of a controversial, blanket amnesty on shore-based line fishing in marine park sanctuary zones.

During the amnesty, declared in March 2013, anglers could not be fined for fishing in these special, mostly remote, stretches of coastline. In other words there has been an 18-month free-for-all from the shore in sanctuary zones.

Scientists and environmentalists agree it is a good thing the amnesty has ended. But there is a kicker: in 10 locations, in five of the state’s marine parks, sanctuary zones will now be revoked to make shore-based fishing permanently legal.

Brou beach, in Batemans Marine Park, is one of these locations and it is a stretch of coast I have known and loved all my life.

And what is happening at Batemans is a microcosm for the entire nation. Marine park areas in NSW and across Australia are faced with being replaced, meddled with and altered to such an extent they are starting to become like the legendary Greek ship Theseus. The Theseus had so many of its components substituted that philosophers began to wonder if it was still the same vessel.

Before the Dalmeny footbridge was constructed more than three decades ago, residents and holidaymakers would have to wade across the estuary to get to the surf beach. Taking into account shifting sands and the ebb and flow of the tide, that meant getting wet anywhere from the bottom of your shorts to the neck of your T-shirt.

Facebook Twitter Pinterest Dalmeny footbridge cross the mouth of Lake Mummuga, giving fishers easy access to the surf beach. Photograph: James Woodford

I vividly remember how the walkway over the lake mouth revolutionised Dalmeny’s civil society: a Sydney harbour bridge for pedestrian seachangers.

But one thing never changed. Brou beach was still only ever rarely fished.

My grandparents owned a little fibro cottage that would today qualify for the micro-house movement, and every day, for weeks on end I would wander along Brou beach and in the forests and dunes backing onto the coast.

Even before I was 10 I was trying to work out how I could live forever in the forests behind Brou beach and catch fish and never have to go home again. Eventually, however, heat or cold, hunger or thirst would reluctantly drive me back to my grandparents’ shack.

The footbridge over Lake Mummuga is where I learned to fish. My grandad taught me how to collect worms for bait on Brou beach. He was a tough but fair taskmaster, whose chiefest sole delights were family, drinking beer and catching fish.

His playground was the marine environment of the Eurobodalla: the estuaries, rivers and the ocean between Moruya and Narooma.

He was no greenie but he was a conservationist, the kind of gnarled, strong man who would sit for hours undoing a “bunch of grapes” of tangled fishing line rather than throw it out and let it become a hazard to sea life.

He caught his own bait (or got me to catch it) rather than buy the frozen prawns in plastic bags that so many fishers leave littered around boat ramps and popular headlands.

He would catch enough for a feed and perhaps a couple of extra to put in the freezer but catching fish wasn’t the main game. He just loved the simplicity of floating down a river in his tinny with his wife and family.

Most of his playground is now Batemans Marine Park. But if he were alive today none of his favourite spots in the marine park would be closed to recreational fishing. The park’s sanctuary zones are a mere fraction of the total area and most are very remote, inaccessible or of no interest to the majority of recreational anglers.

The rezoning of Brou beach will benefit only a tiny minority of anglers who are prepared to make their way to one of the wildest coasts in the state. But allowing even such a small number to fish from the shore, while maintaining a sanctuary zone from beyond the breakers, is like letting someone eat only the icing off a chocolate cake.

After all, it is the shoreline of the beaches and the headlands, soon to have their sanctuary status revoked, that are the focus for marine life. The other problem with allowing a tiny number of people access to these special areas is that many anglers don’t like to walk, resulting in poorly maintained vehicle tracks that lead to terrible erosion.

Facebook Twitter Pinterest Looking north along Brou beach. Photograph: James Woodford

But the worst thing of all is that these kind of contorted-compromise decisions lead to confusion and make it hard to prosecute those breaking the law.

The controversy surrounding the original protection of a place like Brou beach has now well and truly passed. There were no demonstrations demanding it be reopened to fishermen. So an announcement like the one before Christmas looks like bloody-minded score settling at the expense of our marine environment.

Normally such decisions happen on other people’s beaches. Back in 2006 I was happy to see the place where I learned to fish be one of the very few chosen spots on the NSW coast given the highest level of protection. I am dismayed that it will soon, again, be just like everywhere else.