River "improvements" can spell ruin for otters

THEY don't seem very happy, the jeep people. What you glimpse of, them as they whizz past and swing down the horeen is a row of very hored faces.

At the channel there's a pause to engage four wheel drive, then whoosh! on through, salt water surging up under their engine (I imagine it - hope for it - lodging somewhere in the innards, to make expensive trouble later on). Out on the sand they career around in circles, or make exploratory, aimless dashes to the dunes, the sea, the rocks. They almost never get out, though they may sit for a while, then whizz importantly off to do the same thing somewhere else.

The sensible otters keep their distance from the strand in summer, fishing out around the little green islands, Frehil and Govern, where I think their breeding bolts must he. But they do need fresh water to wash the salt out of their coats, and rainwater pools in the rocks cannot always he relied on. So they nip ashore at night at the far end of the strand, taking the shortest route to the streamlets and the lakes behind the dunes.

To watch an otter fishing in a cold, rough sea in winter is to marvel at its robust lifestyle. Yet in many ways our coastal otters have a safer and easier time than those along the inland waterways. Their holts and hunting grounds aren't scraped away in drainage schemes; they don't get run over, poisoned, or torn apart by hounds.

There's no way of knowing what causes the "ordinary" mortality of otters: nature has an amazing way of rendering death invisible. But we do know rather more, now about the violent ends of Irish otters, thanks to the years of work by biologist Dr Liam O'Sullivan, of Mallow, Co Cork.

His national survey of otter mortality in Ireland, just published, covers the period 1984 to 1992. He was helped by a network of informants among the public, including schoolchildren, and by taxidermists and wildlife rangers north and south of the border.

Of some 600 dead otters, more than half were killed on the roads and most of these were adult males, which tend to be more mobile and adventurous. They often died on the same stretch of highway (16 of them in five years, for example, along the River Lee Corridor coming into Cork City). We have signs for drivers, "Beware Deer"; why not for otters?

Another 13 per cent were drowned, often in the cylindrical "fyke" nets used for eel fishing. I read this figure with some guilt, since I once drowned an otter in this way. The fyke net lures eels through successive "funnels" in the net to trap them finally in a bag at the end. In the days of cotton netting, an otter could tear through the mesh to feast on the eels. Now, foiled by polypropylene, the otter learns to find the opening at the other end - an entrance which can so easily he protected by a mesh which lets in eels, but not otters.

Almost 10 per cent of the deaths were due to sport hunting, but "official records of sport hunting mortalities were difficult to access", so the survey's figures are certainly too low. And other fairly frequent forms of violent death include shootings, illegal trapping and fights with domestic dogs.

Overall it's a picture much in keeping with trends in Britain and elsewhere: the percentage of road deaths is very close to the long term British figure. And the actual losses make no serious impact on the status of the Irish otter population either nationally or regionally.

Far more ominous in this respect is Dr O'Sullivan's work on the impact on otters of river drainage and pollution, just published by the Royal Irish Academy. It focuses on a long term study of the Awbeg River system in north Cork. This flows through quiet country around Charleville and Buttevant before joining the Blackwater west of Fermoy - solid cattle country, reeking with slurry when I travelled there earlier this summer.

The upper reaches of the Awbeg have been some of the more polluted watercourses in Co Cork since the 1970s, and "remedial" drainage, repeated every couple of years, has widened and deepened the river and cleared both banks of vegetation. This has swept away the stands of willow and alder that gave the otters a place to rest and changed the fish fauna available for food.

After one such piece of "maintenance", fish stocks were down by threequarters and most of these remaining were tiny stickleback: brown trout, stoneloach and minnows had disappeared. At a mean stickleback weight of three quarters of a gram, the half dozen otters would theoretically need more than 1,060 sticklebacks per day to make up the food they need. By contrast, an undrained stretch of the Awbeg, near Buttevant, was offering trout with a mean weight of 124 grams: half a dozen a day would make up the hulk of the otter's essential diet.

DESPITE all the grants for environmental protection, the polluting from farms is still producing massive fish kills in Co Cork and the south west generally: about 80,000 salmon and trout have died there so far this summer. Dr O'Sullivan, now working with the ESB's Fisheries Conservation Unit at Inniscarra, has found himself in the thick of the problem.

But his long term concern must be with the brutal physical changes that devastate our river habitats and reduce their species diversity. Most of the drainage and "maintenance" schemes are exempt under planning laws and are carried out without any scrutiny. Liam O'Sullivan wants them made public, tested for alternatives, and subjected to conservation conditions.

There are ways of draining land and avoiding floods which do not turn leafy, life enhancing rivers into hare banked canals. Why does the ruthless, ignorant way - and not always even the cheapest - have to be preferred by "practical" man?