TL: PRELIMINARY REPORT ON THE EFFECTS OF DRIFTNETS IN THE
NORTHEAST ATLANTIC
SO: Greenpeace International (GP)
DT: June 1990
Keywords: driftnets atlantic tuna fisheries fish oceans marine
mammals france europe greenpeace reports gp /


"The opinion of many French experts [regarding driftnets] is that
in circumstances where the stock is dispersed or already heavily
exploited, no alternative method of exploitation has been
developed which provides an acceptable economic return to
fishermen." (FAO 1990) 

PREAMBLE

The veritable explosion in the use of large-scale driftnets in
recent years is a significant development on the world fisheries
scene. As more and more countries exercise their right of control
over exclusive economic zones distant water fleets have sought
economical ways to fish the high seas. The large-scale pelagic
driftnet has provided one of the answers to profitability on the
vast expanses of open ocean.  As highly lucrative markets
developed for tuna, billfish and squid and competition
intensified in traditionally fished areas, fleets turned to using
huge driftnets, allowing a single vessel to cover enormous areas
of the sea where little data may be available regarding
distribution of marine life and where stocks may be relatively
dispersed. These nets have permitted tremendous yields for the
high seas fleets despite almost complete uncertainty of the
status of exploited stocks. Little reliable data exists for most
of the target species sought by the driftnet fleets in the
Pacific, for example, and virtually no concerted efforts have
been undertaken to improve the situation, beyond institution of
woefully inadequate observer schemes. 

The effects that the burgeoning large-scale driftnet fleets may
be having on non-target species of fish, birds, marine mammals
and turtles is even more poorly documented. However, all
indications from the few organised observer reports available
indicate that fish stocks are in many cases, such as the South
Pacific albacore, in jeopardy, and that slow reproducing animals
such as marine mammals, which are entangled and drown by the tens
of thousands in the Pacific alone each year may be experiencing
catastrophic effects brought on by the driftnet operations. While
the driftnet fleets have for years been putting forth assurances,
in response to increasing warnings and criticism from scientists,
environmentalists and the fishing industry itself, that they are
not harming the ecosystem with their practices, the evidence
continues to mount that this practice is indeed tremendously
wasteful, indiscriminate and inherently unmanageable. 

While one government after another is instituting bans on the use
of this fishing technique in their national fishing zones, and
regional agreements are taking shape to outlaw driftnets from
entire ocean areas, the driftnet fleets themselves persist in
proposing "technological fixes" to avoid what are now known to be
inevitable incidental catches of non-target fish and other marine
wildlife. It is becoming abundantly clear that increased observer
coverage aboard driftnetting vessels can only serve to document
the unavoidable by-catch and, owing to the inherently non-
selective nature of the technique, can do little if anything to
help avoid it. An enlightened and proactive approach to
regulation of fisheries calls for a cessation of large-scale
driftnet fishing before the inevitable collapses of fish stocks
and wildlife populations becomes a reality in many areas of the
world's oceans. This is so in light of the demonstrably
indiscriminate and unmanageable nature of this fishing technique.

James Carr
Fisheries Co-ordinator
Greenpeace International

EC INITIATIVE TO BAN DRIFTNETS

The widespread use of driftnets around the world has received
considerable attention due to the deaths of non-target fish,
birds, dolphins, turtles and even great whales. Greenpeace is
categorically opposed to the use of high seas and large-scale
driftnets which are responsible for the massive and
indiscriminate killing of marine life. On 22 December 1989, the
European Community joined the consensus of United Nations member
states to pass Resolution 44/225 calling, among other things, for
a global moratorium on all large-scale pelagic driftnet fishing
on the high seas by 30 June 1992. The Resolution describes large-
scale pelagic driftnet fishing as "a highly indiscriminate and
wasteful fishing method that is widely considered to threaten the
effective conservation of living marine resources, such as highly
migratory and anadromous species of fish, birds and marine
mammals". The resolution also expresses concern over the
entanglement of non-target species caught both during the fishery
operations and in lost or discarded netting. Following up on the
UN resolution, the European Commissioner for Fisheries, Mr.
Manuel Marin, supported by Mr. Carlo Ripa di Meana, Commissioner
for the Environment, proposed a draft regulation to ban driftnet
fishing for tunas and billfish such as swordfish in EC waters and
by EC boats in international waters. Although the EC approved a
global moratorium on high-seas driftnet fishing, a few
Commissioners are now opposing a ban in their own jurisdiction,
citing the lack of scientific data. 

Greenpeace supports the establishment of a precautionary approach
to marine fisheries regulation at international, as well as
regional and national levels. This implies that practices which
involve considerable scientific uncertainties as to the risks and
possible damages which could occur through their use are to be
avoided.  Greenpeace appreciates the current move toward a ban on
driftnet fishing in the EC, but thinks that not only driftnet
fisheries for tunas and billfish should be considered. Greenpeace
therefore demands that the European Commission and the Council of
Ministers take immediate measures to: 

* ban all uses of large-scale drift gillnets in the European
Community's waters and EEZ; 

* conduct a thorough review of the impact of the use of small-
scale drift gillnets on target and non-target species in EC
coastal waters; 

* ban the use of all drift gillnets by vessels of the European
Community in international waters and of large-scale drift
gillnets in other countries' waters or EEZ's; 

* push for the conclusion of an international agreement
prohibiting the use of high seas and large-scale drift gillnets
worldwide. 

 INTRODUCTION
Fishermen in a normal mode of unrestrained competition develop
gear and techniques which become more effective with time. These
developments will usually be lawfully applied to new species
and/or new areas, or as new methods in established fisheries.
They are helped in this process by national and international
research organisations who design gear to improve catching
efficiency and to enhance technical conservation. 

Some developments are double edged and have a catastrophic
effect. The development of the puretic power block by Norwegian
purse seiners was such a case. Herring stocks in the North Sea
collapsed shortly after its rapid adoption, and the fishery had
to be closed completely in April 1977 in order to save the
resource. A political will and the development of jurisdictional
capacity in coastal states were the main prerequisites for the
effective enforcement of the closure, and luckily herring are in
a healthier condition now. Currently, there is a danger that such
an event is about to happen again. 

While many European countries are in the process of eliminating
high seas driftnets, the French driftnet tuna fleet is in a phase
of rapid expansion. This expansion has been supported by the
Institut Francais de Recherche sur la Mer (IFREMER), a public
institution engaged in industrial and commercial research.

 The words of warning from a recent FAO Consultation on Large-
Scale Pelagic Driftnet Fishing are relevant at this point: "At
present, the data necessary to carry out thorough impact
assessment of most driftnet fisheries has not been forthcoming,
although preliminary information gives reason for caution in the
conduct of such fisheries."  

Furthermore, the UN Resolution 44/225, which was supported by the
European Community, including France, called for "an immediate
cessation to further expansion of large-scale pelagic driftnet
fishing on the high seas of the North Pacific and all the other
high seas outside the North Pacific." In the northeast Atlantic,
three main species are targeted by driftnets: two Highly
Migratory species, albacore tuna (Thunnus alalunga) and swordfish
(Xiphias gladius) covered by Article 64 and Annex 1 of the 1982
United Nations Convention on the Law of the Sea (UNCLOS), and one
Anadromous species, Atlantic salmon (Salmo salar), covered by
Article 66.  This preliminary report provides information on the
use of driftnets for albacore in the northeast Atlantic; a
subsequent paper will include a discussion of other driftnet
fisheries as well. The text begins with a brief review of the
albacore fishery. The results of the recent Greenpeace survey of
the French driftnet fleet are then released, and compared with
data on bycatch from other driftnet fisheries. Finally, some of
the fundamental biological problems which face managers of the
tuna stocks are discussed.  

 TUNA FISHING IN THE NORTHEAST ATLANTIC

Exploitation of tuna in the north Atlantic comes under the
auspices of the International Commission for the Conservation of
Atlantic Tunas (ICCAT), and signatories include Spain, France,
Portugal, Morocco, Japan and Korea. Three species are of
particular importance: bluefin tuna (Thunnus thynnus thynnus),
yellowfin tuna (Thunnus albacares), and albacore. It is probably
worth pointing out at an early stage that the English name
"albacore" refers to the species Thunnus alalunga (sometimes
Germo alalunga Bonaterre), while the French call this species
"germon". The fish the French call "Albacore" is Thunnus
albacares. 

Stocks of both bluefin and yellowfin recovered somewhat in the
1980's. Bluefin tuna are considered to be in an improved state
due to an entirely fortuitous increase in reruitment (Liorzou and
Cort 1989). This improvement is only relative to low stock levels
in the early 1980's, and does not alter the fact that the eastern
Atlantic bluefin stock had previously been severely depressed
(FAO 1986). Yellowfin tuna catch rates dropped severely in 1983
and 1984 due, it is thought, to an oceanographic anomaly which
made them less susceptible to purse seiners. The spawning stock
has benefited from this (Fonteneau and Diouf 1989).  

The credit for both of these improvements goes to nature, not
enlightened management, and they do not alter the general
conclusions of the Food and Agriculture Organization, which apply
to all North Atlantic tuna species, when they concluded that
there are "large uncertainties in the selection of management
plans and catch and effort data that are representative of the
stock; quantification of the exchange of adults among management
jurisdictions and fishing gears, and identification of the
relationships between the environment and tuna movements" (FAO
1986). The most important tuna stock being exploited by EC fleets
is the albacore, and it is this stock which is targeted by drift
nets. However, the possibility of other tuna driftnet fisheries
operating on the high seas cannot be ruled out. 

 Thunnus alalunga

North and South Atlantic albacore stocks are considered to be
separate, possibly divided by over-warm tropical waters above the
thermocline between 5 and 10 degrees North latitude. Very few
data are available for the Southern stock. The Mediterranean
stock is also considered to be separate and appears to be
restricted in distribution by the Straits of Gibraltar.  

Towards the end of spring the young albacore (years) which make
up the northeast Atlantic surface fishery start a migration
towards temperate regions. They appear towards the end of spring
in the waters off the Azores and move further north as the water
warms, disappearing in the autumn to the west of Ireland. The
young fish seem to have an appetite for thermal discontinuities
and are often found in association with frontal zones. These
zones can be detected by using radiometric airborne or satellite
remote sensing systems, and it is by these means that IFREMER
hopes to direct the (presumably French) fishing fleets to
favourable areas.  

Several countries participate in the fishery for albacore, using
a variety of gear. The Portuguese conduct baitboat fisheries
around the Azores and Madeira between June and August and in late
autumn. Annual catches have been highly variable, from 1,800
tonnes in 1983 to 400 tonnes/year between 1986 and 1988. Spanish
fishing activity is of a fairly consistent pattern. The majority
of catches are made from June to November between the Azores and
the Bay of Biscay, using baitboat and troll. Catches from
1974-1988 in ICCAT Area 1 have varied between 4,000 and 14,000
tonnes in the troll fisheries, and from 8,000 to 18,000 by
baitboats. In 1987 the Spanish fleet caught 25,270 tonnes in the
Bay of Biscay, (ICES Area VIII), and 2,730 tonnes from Azores
waters (ICES Area X). The combined fleet consists of about 600
trollers and 220 baitboats. Taiwanese longline catches grew from
10,000 tonnes/year in the late 1960's to 30,000 tonnes in 1978
and remained at a level of 25-30,000 tonnes until the mid 1980's.
At that point, the fleet started to target species in the Indian
Ocean, and the catch in the Atlantic dropped to around 18,000
tonnes. French catches of albacore were 14,300 tonnes in 1966,
taken by 460 trollers and 86 baitboats; by 1987 this had declined
to 1,830 tonnes by 39 trollers and 15 baitboats. 

Since 1986 French fishermen have been co-operating with IFREMER
in experiments with driftnets and midwater trawls, trying to find
ways of rebuilding the French fleet. Two new combinations have
been used so far. Vessels trolling by day will set driftnets at
night, or trollers, if they are geared up for the task, will form
pair-trawling teams at night.  

 PROBLEMS OF INCIDENTAL CATCH USING DRIFTNETS

In every instance in which driftnets have been examined, a high
level of incidental catch of non-target species has been found.
The available data show the French driftnet fleet to be no
exception. The m/v Sirius, as part of the Greenpeace campaign
against the use of high seas driftnets, monitored the catch of
three French albacore driftnet vessels in June, 1990. Even such a
small number of observations showed an alarming number of species
in the net. In addition to 84 albacore, ten blue sharks (Prionace
glauca), two Ray's bream (Brama sp.) and one common dolphin
(Delphinus delphis) were found in the nets. Most were already
dead, but one immature shark was released alive.  As part of its
statistical observation programme, the Sirius measured the length
of the nets. Lengths ranged from five km to 20 km. This is in
marked contrast to the information supplied by IFREMER and
representatives of the driftnet fleet, which states that the nets
are only five to six km in length. Such levels of bycatch are
entirely consistent with other information available about the
impact of driftnets, both in the north Atlantic and around the
world. If there is currently little evidence of specific
interactions between driftnets and non-target species in the
north Atlantic, this is due to poor research and documentation of
the impact of driftnets, not to the fact that the effects of
driftnets in the northeast Atlantic are different in any way from
those used elsewhere.  

The present survey briefly outlines the various categories of
incidental mortality and then examines the effects of selected
driftnet fisheries in other parts of the world. This will
demonstrate clearly the range of pelagic creatures and the types
of mortality that would accompany any expansion of driftnetting
in the northeast Atlantic. A subsequent report will examine in
more detail the available data, especially in the many driftnet
fisheries for salmon. 

 Non-target species

All fishing methods take non-target species, but fishery
scientists have usually considered only the bycatches of those
species which themselves are the target of other fisheries.
Modelling these multi-species interactions is not a cheap or
simple task even when it involves only a few organisms. Given
also the urgency of developing management strategies for
important food species, it is not surprising that it has been the
commercially important species that have provided most data and
attracted most research effort. This accounts for the poor
documentation of driftnet bycatch. However, as exploitation of
marine species becomes ever more intense and wide-ranging, it
becomes crucial for fishery scientists to assume a broader
ecological perspective in their work, and to include
considerations of the effects of incidental catches of species
which have no commercial value. Common sense tells us that small
quantities of fishing gear working for a short time can kill
large numbers of animals (target species or otherwise) if they
are densely aggregated in the fishing area. This is called acute
mortality and examples include the capture of pursuit-diving
seabirds (loons, shearwaters and Atlantic alcids) which are
feeding in high density flocks on the target species of the net
fishery. This occurred in the Norwegian salmon driftnet fishery,
for instance. Conversely, chronic mortality is that persistent
but obscure threat which kills less densely aggregated species,
ocean wanderers such as the sunfish, and rare species such as the
Cuvier's beaked whale (Ziphius cavirostris).  

Large scale fishing gear such as driftnets are a potential source
of acute mortality as well as a constant source of chronic
mortality. Incidental catches of cetaceans, pinnipeds, sea-birds,
turtles, sharks and fish are a well documented phenomenon of
driftnet fisheries world-wide. In many instances, driftnet
fishing has been banned because of such impacts. 

 Incidental catches in active driftnet fishing.

Recent studies in the Tasman sea indicate the wide range of
species that may be caught in driftnets used in an albacore
fishery. In January 1990, the m/v Rainbow Warrior monitored the
activities of Japanese and Taiwanese vessels for ten days,
recording all catch observed. Over the course of that period, a
total of 1419 tuna (albacore and skipjack, Katsuwonus pelamis)
were caught. The incidental catch consisted of a further 15
species, including blue sharks, common dolphins, Ray's bream, an
ocean sunfish (Mola mola) and a true rarity, a southern
bottlenose whale (Hyperoodon planifrons). Less than 50 specimens
of this rare whale have been recorded, alive or dead. No other
data on incidental catch in this fishery are available, though
anecdotal evidence from observers is in agreement with these
results. The similarity of the species caught incidentally in
that albacore fishery to the species found in the French nets in
the northeast Atlantic (blue shark, Ray's bream and common
dolphin) is striking. In fact, many of the observation sheets
from the two surveillance programmes are indistinguishable.  The
Americans have recently begun a driftnet fishery for swordfish in
the northwest Atlantic. A brief inspection of this fishery by the
m/v Greenpeace in August 1989 revealed 26 swordfish, two bigeye
tuna (Thunnus obesus) and four dolphins drowned in three-and-a-
half miles (5.6 km) of net.  

In the Mediterranean Sea, the Spanish and Italians also use
driftnets to catch swordfish. Little information exists on the
details of this fishery, but it has been shown to have a high
bycatch of cetaceans. A working group of the International
Commission for the Scientific Exploration of the Mediterranean
has expressed concern about this fishery. There is one driftnet
fishery which has specifically addressed the question of bycatch.
An experimental flying squid (Ommastrephes bartrami) fishery was
conducted off the coast of British Columbia, Canada from 1985 to
1987, both within and outside the 200 mile limit. Stretched mesh
sizes of from 115-121 mm were used, and sets ranged from
12.6-46.7 km. 

Bycatch was very high on all three of the vessels, there being
never less than 24 species caught in a season by a ship, and one
ship totalled 37 species caught in 66 sets. The nets caught a
wide range of sizes, from 70 g Pacific saury (Cololabis saira)
and 100 g storm petrels (Oceanitidae) to 2500 kg basking sharks
(Cetorhinus maximus) and a Cuvier's beaked whale, with a mass of
four tons. This was a span of five orders of magnitude. In total,
30 species of fish, over 13 species of birds, nine species of
marine mammals and four species of mollusc were caught (Jamieson
and Heritage 1988).  While this was a specific driftnet fishery
in a discrete area, it demonstrates forcibly that driftnets are
completely unselective. 

Other driftnet fisheries may occur in different areas and utilize
other mesh sizes, but this conclusion is inescapable: a given
mesh size is capable of ensnaring an extraordinary size range of
animals. It is noteworthy that the French albacore driftnet
fishery uses a 90 mm knot-to-knot mesh size, which is comparable
to the stretched mesh size on this Canadian-Japanese fishery. It
is also noteworthy that the bycatch of the fishery was the reason
cited by the Canadian Minister of Fisheries when he banned the
use of driftnets for squid in the Canadian 200-mile zone.
Clearly, a species need not associate with the target species in
order to be caught incidentally to a driftnet fishery.  In
summary, driftnet fisheries for albacore in the Tasman Sea,
swordfish in the northwest Atlantic and flying squid in the North
Pacific all exact a high toll in terms of bycatch of non-target
species. While the data on the northeast Atlantic albacore
driftnet fishery are still few, they are entirely consistent with
these other results. Analysis of data from other driftnet
fisheries support this conclusion, and will be examined in more
detail in a subsequent report.  

 OTHER CONCERNS WITH DRIFTNET TUNA FISHING

A common problem in fisheries conducted by EC countries is that
far too much effort is already being applied to most stocks.
During periods of good fishing, fishermen invest substantial sums
of money in new gear. These large capital inflows act as a means
of maintaining regional employment. Where there are several
sovereign participants in a fishery, the natural tendency is for
political pressure to reinforce this process, and for managers to
allow too high a yield. Governments use genuine scientific doubt
to justify their preferred course of action, so the effort in
fisheries expands. Stock levels become unstable, highly sensitive
to environmental fluctuations and variations in spawning success,
and eventually the stocks decline. The fishermen who, in a period
of optimism and high catches had invested their money, find that
declining returns are insufficient to repay loans. Painful
controls have to be brought in to limit the catching capacity of
the fleets. Such measures are often rendered ineffective by
resistance on the part of fishermen. There are aspects of the
albacore fishery which follow this pattern, and give cause for
concern about the present and potential escalation of effort in
the driftnet fleet. 

The fact that a stock looks healthy is not an adequate reason for
ignoring these problems.  The calculations of maximum sustainable
yield (MSY) for this stock have been made using a generalised
surplus yield production model (Hsu and Liu 1989). This type of
model is not altogether satisfactory and has been criticised by
fisheries experts as often yielding estimates that are overly
optimistic when used on inappropriate data (Pitcher and Hart
1982). While this does not mean that the results for the albacore
stock are totally inaccurate, it does suggest that caution is
warranted: a great deal of care should be taken before using them
to justify an expansion of effort which it may be difficult to
remove at a later date. Furthermore, managing fisheries on the
basis of MSY has been widely recognized as dangerous and allowing
no margin for error or natural fluctuations (Pitcher and Hart
1982). Estimates of fishing mortality to be used in such models
are generally derived from catch statistics. However, such
statistics will represent only a fraction of the true fishing
mortality, if that term is defined as "dead fish" due to fishing
operations. The extra mortality is of several different types.  

* dropout mortality refers to dead fish which have fallen from
the meshes prior to hauling back the net;  

* haul-back mortality refers to fish lost as a result of recovery
of the net;  

* escapement mortality refers to fish which are caught by, but
then escape, the meshes, but die later as a result of the
encounter, such as from scale damage.  

The extent of these additional mortalities depends on local
conditions such as weather, gear handling practices, and the
relative frequency of sizes in the shoals of fish encountered by
the gear. For Scombriformes such as tuna, vulnerability to scale
damage appears to be high, so many fish which swim away will be
damaged and die. Moreover, tuna have a relatively high metabolic
rate, so a large proportion of those that dropped out of the net
would have been dead after hanging in the net for a very short
time, due to rapid asphyxiation without forward motion to supply
oxygen. Total mortality of the albacore due to driftnets is
probably not accurately measurable, and is in an indeterminate
relation to the catch. 

Thus the total effect of driftnets on the stocks is uncertain,
and not accounted for in the stock assessments. It is difficult
to avoid the conclusion that driftnets are wasteful in terms of
biologically defined objectives. A further cause for concern is
the fact that driftnets catch predominantly immature fish.
According to data from Liorzou (1988), 50% of female albacore
have reached maturity at 95 cm in length, and still only 75% at
98 cm. The modal size for driftnets (filet derivant) is 63 cm,
with few fish being caught that are larger than 83 cm. Pelagic
trawls (chalut pelagique) and trolls (ligne) have similar modes,
though trawls catch somewhat larger fish as well. For longlines
(palangre) and baitboats (pole and line, canne) the mode is 88
and 79 cm respectively. Such selection of immature fish increases
the risk of recruitment over-fishing. In summary the rapid
escalation of the driftnet fishery presents a classic recipe for
disaster. The stock assessment models are prone to creating
artificially optimistic results, and take no account of a
potentially large component of the total mortality resulting from
driftnets. This particular fishing technique takes predominantly
immature fish. 

 THREATS TO CETACEANS LIVING IN THE WATERS OF THE NORTH-EASTERN
MID ATLANTIC 

 1. Species-rich waters

In the triangle of ocean bounded by the Atlantic coasts of
France, North Africa and the Azores a wide range of cetacean
species may be encountered. This area is likely to include the
more northerly edge of the ranges of some warm water favouring
species, like Spotted and Brindled Dolphins (Stenella plagiodon
and S. attenuata respectively) and also the southern most extreme
of species like the Atlantic Whiteside Dolphin and Whitebeak
Dolphin (Lagenorhynchus acutus and L. albirostris) which have
primarily North Atlantic distributions and seem to prefer colder
water. Furthermore, in the North-eastern Mid Atlantic both
species of Pilot Whale, the Long Fin (Globicephala melaena) and
the Short Fin (G. macrorhynchus) are also found. The Short Fin
occurs mainly in the tropical and sub-tropical parts of the
Atlantic, Pacific and indian Oceans. Further north and south its
place seems to be taken by the Long Fin which has populations in
the North and South Atlantic as well as in the South Pacific and
Indian Ocean.  Moreover, in these same waters, cetacean species
and populations which favour inshore conditions, such as the
Harbour Porpoise (Phocoena phocoena), and those which are more
truly oceanic, such as the Great Sperm Whale (Physter
macrocephalus) will all be found. In all, an estimate that as
many as 35 different cetacean species might be found in this one
small part of the sea can be made. Some may only be present at
certain times in their yearly migrations and others may be fully
resident. 13 of the species likely to be found here are small
toothed-cetaceans, commonly called "dolphins" and "porpoises",
and the rest are more generally referred to as whales. Seven of
the world's ten species of Baleen whale may be found in these
waters at certain times.  

 2. Status and Protection

In general, very little is known about the population size,
distribution and overall status of cetacean species. Even for
those which have been quite extensively studied, and the focus of
attention has been on the great whale species for many years,
population estimates are difficult to make and fraught with
uncertainty. Recently, previous estimates of great whale
populations have been found to be grossly high. Comments on the
abundance of most cetacean species are normally made on the basis
of how often the animals are observed in the wild or how often
they strand (both dead and alive). These are likely to give false
impressions of real numbers, however, as the behaviour of
different species favour different sorts of observations. For
example, some of the dolphins are actually attracted to boats and
collect around them, even "bow-riding" at times. 

Whereas other cetacean species, for example some of the Beaked
Whales (Mesoplodon and Ziphius spps), are very rarely seen either
dead or alive. This may, in part, be because beaked whales
assiduously avoid marine traffic. Indeed, the first indication
that they are in the area would probably be when they get
entangled in nets! In the absence of hard evidence of healthy
populations, and bearing in mind the many threats which cetaceans
are subject to (reviewed below), it seems most suitable that they
should be afforded fully protected status. So it is that the
Berne Convention (which has been ratified by all the Member
States of the European Community, except for France, which is in
the process of doing so) lists 17 of the species likely to occur
in this part of the Atlantic in the "strictly protected" category
(see table 1) 

 3. Threats

 a. Drift Nets

It is well established from investigations in the Pacific that
drift nets remove not only target fish from the waters where they
are used but virtually anything bigger than the mesh size. This
will include whales and dolphins and there is no reason to
believe that any drift net fishery in the Atlantic will not have
the same effect as those reported in the Pacific. The only real
difference is that cetaceans and the impact of fisheries on them
are less well studied in the east Atlantic.  The drift netting
operation in the North-eastern Mid Atlantic began in 1987 and it
is possible that it has already severely impacted cetacean
populations which occur in the area.  

 b. Other fisheries

Dolphins and whales may be part of the bycatch of other forms of
fishing as well. For at least the last three years hundreds of
dolphins have been washed up in various stages of decay on the
French Atlantic coast. The causes of these mortalities is not
known but it seems most likely that dolphin migrations have been
intersecting a major fishery operation somewhere off the French
coast. One other possible impact of fisheries may be that if fish
stocks are significantly depleted by over-fishing, then cetaceans
and other marine wildlife may go hungry. Fishermen sometimes try
to attribute the blame for declining fish stocks on marine
mammals but there is no proof that marine mammals reduce fish
populations - indeed it is more likely that if we over-fish then
the marine mammals starve.  

 c. Pollution

Pollution forms an unquantifiable but nonetheless potentially
major threat to cetaceans. Ubiquitous contaminants like DDT and
PCBs accumulate in the tissues of marine top predators and there
is evidence that, of all mammal species tested, cetaceans are the
group least able to cope with chemical contamination.
Reproductive failure and suppression of the animals' immune
systems are possible consequences and there is some evidence from
dolphins of both effects.  

 d. Mass Mortalities

It has become apparent recently that hundreds of marine mammals
may die in "epidemics". The North Sea seal epidemic is but one
example as there have also been two recent die-offs of bottlenose
dolphins and a mysterious mass mortality of humpback whales off
America in the last few years. It is quite likely that
significant numbers of cetaceans could die at sea without ever
causing any concern unless bodies reached the shore. So these
major losses of animals from populations may occur undetected. 
To what extent man has induced the observed mass-mortalities,
perhaps through putting wastes into the sea or by changing the
climate, remains to be determined. Faced by all these little
understood threats, the future of cetacean species and
populations is uncertain. They should not be further challenged
by drift net fisheries. This is a form of fishing which is
unnecessary and perpetuation of which shows no regard for the
future of either european fishermen or wildlife. For the good of
both it should be stopped.