Birds have always been caught in fishing nets. But the introduction
of fine, synthetic materials in the 1960s caused a radical change in near-shore
fishing in England and Wales. Synthetic nets are virtually invisible, and
catch more fish than equivalent nets made of natural fibres. Fixed-net fishing
(as opposed to trawling) underwent a revival as grounds which were too rough
for trawling became exploitable with the new gear. So the problems for seabirds
have almost certainly become more serious.

Fixed nets are weighted at the bottom and held vertically in the water
by floats. Drift nets are made from the same type of netting, but they are
unsecured and so move through the water. Offshore drift-net fisheries have
alarmed conservationists because they catch dolphins, seals, birds, sharks
and other marine animals in addition to the fish targeted by fishermen.
Concern over these ‘walls of death’ led to a United Nations resolution that
decreed a moratorium on drift-net fishing. But ‘small’ drift nets (2.5 kilometres
or less) remain legal, and near-shore drift-net fisheries are traditional
in Britain.

A review published recently by the Royal Society for the Protection
of Birds and the World Wide Fund for Nature documents serious concern about
the worldwide effects of fixed nets on seabirds. Birds such as guillemots,
which can dive to depths of 100 metres, are often caught in nets set on
the sea bottom. Conservationists are concerned about many species-in Britain,
razorbill, guillemot and divers are listed.

To be fair, the evidence for a major impact of synthetic nets on seabird
populations is a matter of conjecture, but the large numbers of birds involved
in some cases are alarming. The west Greenland salmon drift-net fishery
killed hundreds of thousands of auks each year in the late 1960s and early
1970s; most of these were Brunnich’s guillemots. A quarter of a million
deaths spread through an Atlantic population of perhaps 20 million birds
seems like a pinprick but if all these deaths are concentrated in one particular
breeding population than major changes might result. It is easier to produce
worrying numbers of dead birds than to prove that any fishery has a major
impact on seabird populations. But where there is enough evidence for concern,
surely fisheries should proceed carefully, and where there is doubt, they
should take a precautionary approach.

Recent studies by the RSPB have shown that a small fixed-net fishery
in St Ives Bay, Cornwall, kills hundreds of seabirds each winter. This fishery
is unusual only because it operates so close to the shore that dead razorbills,
guillemots and shags can be counted from land as the nets are hauled in.
On 1 February 1988, 536 dead auks were taken from five nets within sight
of the shore. Most winters there are probably hundreds of birds being killed
in this way but sometimes there may be thousands of deaths. If agricultural
practices killed birds on this scale there would be an outcry.

The scientific problems in assessing the impact of fisheries on seabird
populations are enormous. Estimating the numbers of dead birds requires
expensive, long-term studies covering wide areas. Knowing how many birds
are killed does not tell you much about how the breeding population will
change. Losses of wintering birds may be compensated for by the breeding
success of the remainder. Conversely, showing declines in breeding numbers
does not tell you how much of this decline is due to deaths in nets.

So, has the scientist much to offer? We could suggest that conservation
organisations spend massive amounts of money on studying the impact of nets
on seabird populations, but we believe that this lets the fishing industry
off the hook too easily. Fishermen need to take the lead in minimising the
harmful effects of fixed nets on birds. These measures need not be expensive,
and it would be best to test the cheap and easy methods first. For example,
dyeing nets to make them more conspicuous might cut seabird deaths without
affecting catches of fish.

If cheap, simple methods do not work, then regulations on the use of
nets may be needed. In Scotland, synthetic nets are illegal because they
would damage salmon stocks. Short of banning these nets, one could introduce
quotas on the numbers of seabirds that it was legal to kill for each tonne
of fish landed. Such by-catch quotas are already common: they usually refer
to the number of other fish species that the fishery can take, but there
is no reason why this should not be extended to birds.

We would like to see the Ministry of Agriculture, Fisheries and Food
taking wider responsibility for the environmental effects of fishing practice.
The MAFF is in the best position to evaluate the problem, assess which nets
are the greatest threat, and identify those sections of coast where most
birds are killed. It would also be in the interests of fisheries to know
the impact of synthetic nets on fish stocks.

At the North Sea Ministerial Conference in The Hague in March 1990 the
British government committed itself to ‘improve the protection of marine
wildlife’ and to find a ‘common and coordinated approach for developing
species and habitat protection, and develop appropriate conservation measures
for the North Sea, especially with regard to seals, sea and coastal birds.’
Fine words, but if seabird mortality were ever shown to be a major problem
for Britain’s internationally important seabird populations it is not clear
whose job it would be to take account of this. The MAFF could argue that
its remit covers only the regulation of fisheries for fishing and does not
cover wider environmental side effects. Such confusion of roles is rife
in Westminster and will be a major block on the implementation of conservation
by the government.

Fixed nets sometimes kill large numbers of seabirds. Society as a whole
must decide what level of environmental side effect is acceptable, and views
are likely to differ. But in the case of fixed-net fisheries the full environmental
effects of having cheap fish on your plate seem to be hidden.

Mark Avery (top) and Mark Robins work for the Royal Society for the
Protection of Birds.

Seabirds do not make it easy for us to get to know them. Many species
feed far out at sea, coming ashore only to nest for a few brief months of
the year. And then many of them choose to nest on remote islands, on steep
cliffs or underground; many come ashore only at night. If you approach some
terns and skuas when they are nesting, they hit you on the head. Perhaps
it is the mystery that attracts many of us to such birds. Alan Richards
has been bitten by the seabird bug, and probably by some seabirds as well;
and his enthusiasm shows throughout his book.

Richards sprinkles the text with anecdotes and information, but it is
the photographs that grab our attention. Overall the photographs are very
good. Many of the species, however, are shown at their nests and the portraits
of single nests do not always conjure up the bustle and movement, the noise
or the smell of seabird colonies. The pictures of a flock of common terns
diving for fish and the colony of ring-billed gulls are full of atmosphere.

I was glad to see that many of the terns photographed carry numbered
metal rings that will identify them through their lives. Ringing has helped
to dispel a little of the mystery about seabirds. Take two examples from
current issues in conservation: the roseate tern is declining throughout
its Atlantic range and, unfortunately, its British and Irish population
is now less than a quarter of the 2000 pairs that Richards suggests. Because
many roseate tern chicks were ringed in the past we know that this species
travels to west Africa for the winter where it faces persecution by man.
This provides a hefty clue towards finding the cause of the species’ decline
and implementing effective conservation action. The ringed adult Arctic
Tern would be well advised to avoid Shetland until fish stocks there recover
because, since 1984, tens of thousands of Arctic Tern chicks have starved
to death. It was local ringers who sounded some of the first alarm bells
when they noticed the dropping numbers of chicks to ring.

If you study terns, it is difficult to enthuse about gulls as many species
are hulking great monsters, but here photographers have produced eye-catching
portraits of Franklin’s, Bonaparte’s and Sabine’s gulls. To look at, Herring
and Audouin’s Gulls are superficially similar so one wonders how the Herring
Gull has managed to become so common that it is treated as a pest whereas
Audouin’s is the world’s rarest gull and numbers only 3500 pairs in a few
Mediterranean colonies.

I have one complaint. The photographs of petrel chicks look ghastly
and must have involved removing the chicks from their burrows – a practice
which can cause desertion. Was this risk worthwhile to obtain pictures of
these rather ugly balls of fluff?

All in all, this is a book for people who like pictures of seabirds.
You would be well advised to check some of the information in the book with
up-to-date reference works. But the seabirds still keep their mystery. Almost
all of the photographs are snatched in the few weeks when these birds share
our terrestrial world. The rest of the time we must stare out to sea and
wonder.

Mark Avery works for the Royal Society for the Protection of Birds whose
headquarters in Bedfordshire are not ideally placed for studying seabirds.

The prudent course would be to suspend fishing pending evidence of an
increase in the numbers of sand eels. Instead, the Department of Agriculture
and Fisheries for Scotland (DAFS) has used the inadequacy of its own data
on the impact of the fishery as an excuse for allowing continued fishing.
Although the DAFS has introduced measures to avoid catching the youngest
sand eels, exploitation of older fish, including immatures which have yet
to breed, continues. The fishery’s effect on the chances of a return to
high levels of young sand eels entering the population is unknown.

There is some good news. Researchers are now investigating the numbers
and vertical distribution of sand eels near the seabird colonies of Shetland.
This research, which is funded jointly by the government, the Royal Society
for the Protection of Birds, the World Wide Fund for Nature and Cadbury,
may produce useful information on the current behaviour and distribution
of sand eels. But it is unlikely to throw much light on the low numbers
of young sand eels joining the population in recent years.

Now the gloom. Arctic terns in Shetland have again failed disastrously;
probably no young fledged this summer. In 1980, surveys by the RSPB counted
32 000 pairs; only about a quarter remain. Further crashes in the number
of terns are almost certain. The first poor breeding season was in 1984.
Arctic terns do not breed until they are four years old, so we have seen
the effects of only the first three years of poor breeding; four more years
are in the pipeline.

Along with many other seabirds on Shetland, the main diet of the terns
is sand eels, small fish that spawn in sandy sediments in winter. Chicks
appear to depend almost entirely on young fish in their first year. Interestingly,
puffins seem to have switched from sand eels to rockling and other fish.
Although their success at breeding was poor, this has saved them from another
year of complete failure. Arctic skuas have failed to rear young on mainland
Shetland and the isle of Fetlar, but have raised young on the islands of
Yell and Unst. Kittiwakes have failed for the sixth successive year.

We are witnessing the most sustained seabird disaster in Britain’s history
– a situation so serious that all potential ameliorating actions should
be taken. The DAFS insists that it needs proof of overfishing before it
can ban fishing, yet it knows that such proof is unobtainable because methods
of assessing stocks of sand eels are inadequate.

Last year, the department thought that 19 billion first-year sand eels
had entered the population in 1986, but now the estimate is 49 billion.
Figures for 1988 have changed from 21 billion to 1 billion. If the fishery
is to be managed sustainably, we need reliable demographic models and accurate
stock estimates. In fact, we have neither.

Roger Bailey, a biologist with the DAFS, has claimed that there is no
firm evidence that stopping the fishery would help stocks. The truth is
that the department lacks firm evidence about even the size of stocks.

The DAFS may be pinning its hopes on the possibility that the decline
in sand eels is due to natural changes – in sea currents or predators, for
instance – and that these might just go away. No evidence has linked such
changes to the breeding success of seabirds on Shetland until a recent paper
by Mike Harris and Sarah Wanless of the Institute of Terrestrial Ecology.
They suggest that the breeding success of kittiwakes declines as you move
northwards along the British east coast (Journal of Applied Ecology, vol
27, p 172).

If Shetland were just the worst end of this overall trend, the Shetland
sand eel fishery would be unlikely to be involved in the breeding failures
of the seabirds. However, the latitudinal trend in nesting success disappears
if you exclude the Shetland colonies from the analysis. So the data suggest
Shetland is a special case.

Harris and Wanless tentatively suggest that changes in the penetration
of Atlantic water into the North Sea might be related to the lack of sand
eels. They show that sea temperatures around Shetland between 1974 and 1988
are negatively correlated with sand eel recruitment – that is, the lower
the temperatures, the more young sand eels entered the population. In support
of this idea, they cite a paper published by Paul Hart in 1974. Hart’s data,
however, indicate a slight positive correlation between temperature and
recruitment – with higher temperatures linked to higher recruitment – so
any causal link is far from clear.

Although we would argue with their interpretation, Harris and Wanless
present new data that contribute to our understanding of the problem. In
contrast, Lord Sanderson, the DAFS minister until last month, seemed to
obscure the issues with spurious claims about the effects of seals on the
sand eel population.

In letters to the RSPB and concerned members of the public, he maintained
that seals took twice as many sand eels as the fishery and therefore had
an important effect on the recruitment of young sand eels. When challenged
to justify this view, he admitted that scientists at the DAFS consider it
unlikely that seals prey on the very young sand eels and that the studies
of the seals’ diet were made in areas away from Shetland. We hope that the
new minister, Lord Strathclyde, will be less keen to fasten on to unconvincing
alternatives rather than admit that his department does not know the causes
of low sand eel recruitment.

No one nows whether fishing has caused, or helped to cause, the breeding
failures among the seabirds in Shetland. There is no reliable model that
can predict whether a ban on fishing would enhance stocks of sand eels.
Despite this ignorance, the DAFS firmly insists that lack of good evidence
for the fishery’s impact should be treated as equivalent to good evidence
that it has no harmful impact. The precautionary principle, supported by
the British government at the Third North Sea Conference in March in relation
to pollution, seems to be ignored when it comes to fisheries.

We challenge the DAFS to state what evidence it would regard as firm
enough to warrant closure of the Shetland sand eel fishery. What would be
the critical test to decide the issue? If, as we suspect, such data do not
exist, we challenge the DAFS to explain how it can maintain that its management
of this fishery has any scientific basis.

Mark Avery and Rhys Green are biologists working for the Royal Society
for the Protection of Birds, in Sandy, Bedfordshire.