The raw splendour of the Co Antrim coast draws visitors from across the world. Facing seawards, they contemplate timeless scenes that seem almost unchanged since it was first settled thousands of years ago.
But appearances are deceptive. Beneath the waves, today's seas are profoundly different from those of the past and are still changing fast.
In the 16th century, Spain paid the British Crown £1,000-a-year to fish in Northern Ireland's rich waters. Nineteenth century inventories described these coasts as abounding with the finest cod, ling, skate, turbot, conger and other prime fish.
Mighty herring shoals visited seasonally and its sea loughs were renowned for their superb oysters and dense shellfish beds, prized as food and valued as fishing bait. In 1830, Londonderry and Antrim boasted nearly 3,000 fishermen working from more than 700 boats.
Today, those seas have seen their life dwindle in the face of escalating fishing pressure, ignorance and neglect.
Northern Ireland now borders two of the most overfished and degraded seas in Europe: the Irish Sea and Firth of Clyde.
What is surprising about their fates is the speed of collapse and the fact it has taken so long to notice that there is anything wrong.
In both seas, fisheries prospered throughout much of the 20th century as the fishing fleet mechanised and became more powerful.
There were early-warning signs in the decline of herring fisheries through the 1960s and 1970s, but overall catches of cod, haddock and other bottom fish held up well.
Then, in the mid-1980s in the Clyde and after 1990 in the Irish Sea, landings of these fish went into a terminal nosedive, to the point of virtual disappearance now.
These collapses would have been catastrophic had there been nothing left to catch. But there are still valuable prawns and scallops to be had.
They are taken using fine-mesh trawl nets for prawns and steel dredges with downward-pointing teeth for scallops.
It is the rise of these fisheries in the last few decades that we should look to for the cause of collapse in the rest.
Together, prawn trawlers sieve and scallopers rake virtually every square metre of these seas. Prawn boats scoop up juvenile fish long before they mature and reproduce, while scallopers sweep away nearly everything that lives on the seabed, destroying fish habitats.
It was failure to recognise the enormous collateral damage of scallop-dredging that led to Northern Ireland's most notorious conservation lapse - the destruction of Strangford Lough's horse mussel beds.
Strangford's importance to marine life has been recognised with just about every conservation designation on offer: Marine Nature Reserve, Special Area of Conservation, Special Protection Area, Area of Special Scientific Interest, European Marine Site and Ramsar wetland.
But laws alone are worthless.
At about the size of a human hand, horse mussels are larger versions of the blue mussels commonly bought from fishmongers. They once formed dense beds that crusted huge areas of seabed, but have hung on only in places that have escaped trawl or dredge, such as sea loughs.
Sadly, in spite of all the legislation, few people thought it important to protect Strangford Lough from scallop-dredging and so its horse mussel beds were smashed to pieces, taking with them hundreds of other species.
This might seem like an unfortunate and isolated incident, but it speaks volumes of our neglect of life in the sea. Successive governments have thought that protection can be achieved without ever needing to scale back fishing.
While such a position helps garner fishing industry co-operation it is disingenuous and, ultimately, as destructive to the fishing industry as it is to mussels. When fish run out, the industry will disappear, too.
These are difficult times for life in the sea and overfishing is not the only reason to seek a management rethink.
The world is changing fast. Irish seas have warmed about 1C in the last 50 years and become more acidic as carbon dioxide emissions have dissolved in the water.
Acidification is making life harder for thousands of species that create chalky skeletons, or shells, from calcium carbonate (which includes scallops and prawns).
These stresses are compounded by pollution, coastal and offshore developments, even underwater noise.
As the seas become more hostile to life, they become more hostile for us.
Polluted beaches heaped with rotting weed have claimed lives in France, dead zones choke life from huge areas of the Baltic, toxic plankton blooms hospitalise beachgoers in the Adriatic and plagues of jellyfish shut down power stations in Scotland and wipe out farmed salmon in Ireland. None is a direct result of overfishing, but all are worse for it.
The bad news is that we will struggle for decades more to control climate change and population growth, so conditions will get worse before they get better.
This is why we need a new deal for life in the sea: much greater protection, less destructive fishing and less pollution of all kinds.
If the seas are to continue to meet human needs through the coming century, we need urgently to recover their abundance and variety of life and rebuild degraded habitats.