The rise and rise of the 'Dublin Bay prawn'


Another Life / Michael Viney: At four years old, family annals insist, I asserted that "They's not frimps, they's prawns!" The significance of this, never momentous, has been lost with time.

I mention it merely to show an early (and dogmatic) acquaintance with crustacea, in a home often fragrant with simmering fruits of the sea. Later, after the war, when landmines and barbed wire were cleared from the shore, I did my Huckleberry bit in rock pools under the chalk cliffs and netted marvellous harvests of the common prawn, Palaemon serratus, the length of one's finger. The pools have now gone, submerged beneath the floating cocktail party of the Brighton Marina.

What brought all this on was hearing how pleased Irish fishermen were with their Christmas consolation from Brussels: an 11 per cent increase in the Total Allowable Catch (TAC) for "prawns" to help make up for cuts in the quotas of almost everything else worth overfishing for. The animals in question are, of course, not the crustacea of my childhood, but the "Dublin Bay prawn" or "Norwegian lobster", Nephrops norvegicus. As "scampi", the caviar of the masses, consumption has rocketed, so that Nephrops is now the Irish fishing fleet's second most valuable catch (after mackerel), earning something over €28 million a year. Dissecting a pub lunch in Galway recently, I discovered (from a candid but defiant waitress) that scampi now came in a "reconstituted" form so that chefs squeeze it out in cylindrical ribbons, like toothpaste. This shows how often I get out.

Nephrops (its big, black, beady eyes are kidney-shaped, hence the name) is bright orange even before it is cooked: a miniature lobster that can reach 25cm from the tips of its slender claws to its fan-shaped tail. It lives in galleries carved in seabed mud the consistency of chocolate mousse, where the females are currently holed up with their next clutch of fertilised eggs. The males are much bigger and territorially aggressive, spacing their holes in quarrelsome colonies: 68 holes to 100sq m is a current record density from the North Sea. They stroll out to scavenge, alerted to anything remotely edible by mere molecules of scent.

Why "Dublin Bay prawns" should ever have found their market can seem a bit odd, knowing what we do about the the mud on the city's doorstep. But the term applied more to the harbour of origin. Howth, Clogherhead and Skerries muster the 70 inshore trawlers that drag "tickler" chains ahead of their nets through the fine mud of the sheltered western Irish Sea, sweeping up almost half the national Nephrops catch (raised for this year to 8,167 tons).

Mud or muddy sand is not confined to estuaries or bays, but can also accumulate well offshore. Next to the shallow Irish Sea, the biggest contributions to the national Nephrops catch now come from grounds to the west of the Aran Islands and even out on the Porcupine Bank (where, it seems, the little lobsters may live to more than 15 years, compared to the eight or nine they are thought to expect in the Irish Sea).

In many ways, "prawn" fishing is an ideal harvest for Irish coastal fishermen, using smaller trawlers (13 to 38 metres on the Aran grounds) and less fuel, and spending less time away from home, to catch a high-value product. But the number of boats targeting Nephrops off the southeast and southwest of Ireland has more than doubled since the quotas for monkfish (another bottom- dweller) have been enforced, and this year's 11 per cent increase comes amid inevitable concern from ICES (International Council for the Exploration of the Sea) about the need for more research into stocks and tighter management.

Already, the animals are getting smaller. Nephrops has been recorded with a carapace length (the middle, most edible, bit) of up to 8cm. In recent years, reports the Marine Institute, individuals with a carapace longer than 6cm have been rare in Irish waters. But the lobster is notoriously difficult to research. Unlike fish, which store up age-rings in their ear-bones, or otoliths, Nephrops moults its shell as it grows, making age hard to measure, and its burrowing habits make it difficult to count.

Past studies have focused on the stock in the western Irish Sea, fished for the past 20 years with no apparent decline (though now with controls on days at sea). Since 2001 the Marine Institute has also made underwater surveys there and on prawn grounds in Galway Bay, using a sled-mounted TV camera to get a time-series record.

Only when enough pictures are analysed can proper management begin. By that time, too, it should be clear whether "tickling" the seabed ecosystem with chains, repeatedly, is a really sustainable method of fishing.