TL: Technical Report on the Situation of Small Cetaceans in the Mediterranean and Black Seas and Contiguous Waters, and the Impact of Fishing Gear and Fishery Practices on These Animals SO: Greenpeace International DT: March 1991 (?) Keywords: greenpeace reports whales dolphins oceans marine mammals species endangered mediterranean europe north africa egypt conferences fisheries fishing deaths gp / PREFACE At its 9th meeting, in December 1989, the Standing Committee of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) authorized the creation of an informal working group on small cetaceans in the Mediterranean, comprising the Secretariats of the Bonn, Bern and Barcelona Conventions, IUCN, Greenpeace and the Chairman of the Small Cetaceans Working Group of the Bonn Convention. Greenpeace agreed to produce two working papers for the meeting of the informal group: a paper on international legal protection for small cetaceans in the Mediterranean and a technical paper on the situation of small cetaceans in the Mediterranean and the impact of fishing gear and fishing practices on these animals. The informal working group met from 25-27 February 1991 in Palma to discuss both papers. The papers have been revised in accordance with comments received from the participants in the meeting. The authors of this paper were Ricardo Aguilar, Xavier Pastor and Assumpta Gual of Greenpeace Spain, Fabrizio Fabbri of Greenpeace Italy, Mark Simmonds of the Greenpeace Ecotoxicology Unit at Queen Mary and Westfield College, London, and Asuncion Borrell and Esteve Grau of the Faculty of Biology of the University of Barcelona. Alex Aguilar of the University of Barcelona kindly reviewed the text. Note. "Contiguous waters" for the Mediterranean covers the area surrounding the Atlantic part of the Gibraltar Strait, and for the Black Sea includes the Azov Sea as well. INTRODUCTION The presence of about 20 different cetacean species has been reported in the Mediterranean Sea, about half of which form part of Atlantic populations entering the sea only sporadically. The Black Sea on the other hand is more limited in terms of species, yet includes a species termed as rare or absent from the Mediterranean. Only ten small cetacean species are sighted frequently in these seas. They are In the Mediterranean Sea: - Rough-toothed dolphin (Steno bredanensis) - Risso's dolphin (Grampus griseus) - Long-finned pilot whale (Globicephala melas) - Cuvier's beaked whale (Ziphius cavirostris) - Killer whale (Orcinus orca) - False killer whale (Pseudorca crassidens) - Striped dolphin (Stenella coeruleoalba) In the Black Sea: - Harbour porpoise (Phocoena phocoena) In both seas: - Common dolphin (Delphinus delphis) - Bottlenose dolphin (Tursiops truncatus) Species distribution and frequency vary from coast to coast. The Mediterranean Sea can be divided into eastern and western basins, and species diversity and abundance differ greatly in the two areas. For several reasons, cetacean fauna in the western basin is much richer than in the east. The western basin is subject to a greater Atlantic influence, and species and populations from that ocean occasionally enter the Mediterranean Sea through the Straits of Gibraltar, the only natural route of access from the Atlantic ocean. This has been evidenced by isolated instances of sightings of species such as the humpback whale (Megaptera novaeangliaea) close to the Balearic islands (Aguilar, 1989), ziphiids such as Blainville's beaked whale (Mesoplodon densirostris) or Sowerby's beaked whale (Mesoplodon bidens) stranded on Spanish shores (Casinos and Filella, 1981; Hershkovitz, 1966) and the dwarf sperm whale (Kogia simus) found in Italy (Centro Studi Cetacei, 1988). The harbour porpoise (Phocoena phocoena), once abundant in the Mediterranean, (Graells, 1889; Barcelo, 1875; Companyo, 1863), are now considered to have vanished from this sea, and the last details on their presence there dates back to the turn of this century. Only a very few exceptions exist, such as the case of the individuals found on African coasts in the last few years (Ktari-Chakroun, 1980; Duguy, Casinos et al, 1983) or in Southern Spain (Rey and Cendrero, 1982). Wildlife richness in the western basin includes not only cetaceans, but also fish and other marine organisms. The Mediterranean Sea contains highly productive areas due to nutrient blooms generated by the winds, creating upwellings in areas like that between the Ligurian sea and the Gulf of Lyons, or the coasts of north Africa. This characteristic increases the concentration of marine organisms, including fish stocks and predators such as small cetaceans. Surface currents, which cross through the Straits of Gibraltar and circulate in the western part of the Mediterranean basin, are also an important factor in explaining the presence of cetaceans there. These currents are used by different shoals of fish, including tuna (Tunidae) and swordfish (Xiphias gladius), to aid them on their migration to breeding or spawning areas. The migrations are followed by predators, including killer whales and sperm whales, which enter the Mediterranean mostly in pursuit of migrating prey. Marine organisms have also been known to enter the Mediterranean Sea through the Suez canal. Despite the large volume of maritime traffic in this area and the fact that the canal is man-made, which makes this a route of access which is far from ideal for cetaceans, there have been several instances of warm water species such as the Indo-Pacific humpback dolphin (Sousa chinensis), which exclusively inhabits the Indo-Pacific region, entering the canal and even reaching as far as Port Said in the Mediterranean Sea. For the most part, however, these are isolated cases and, save for killer whales and sperm whales, which are sighted more frequently, other species cannot be considered part of the Mediterranean cetacean fauna. It should be noted that there is still a great lack of information concerning the biology, behaviour and abundance of cetaceans in the Mediterranean. Data available so far servesonly to give a general overview of distribution and frequency in the different regions. Research has been based mainly on the systematic collection of data on stranded animals, accidental captures by various types of fishing gear and information from privatelyowned vessels of sightings on the high seas. There are very few research programs on cetaceans in the Mediterranean, and they are mostly limited to specific areas and populations. Most data has been obtained for the western basin, while in the east information is very scarce, allowing only for speculation. The only species present in the Black Sea but not in the Mediterranean is the harbour porpoise (Phocoena phocoena). This species is currently under threat, as are the Black Sea populations of the bottlenose dolphin (Tursiops truncatus) and common dolphin (Delphinus delphis). This is mainly due to the deliberate capture of these three species in the Black Sea and also to habitat degradation, including high pollution levels (Prescott and Fiorelli, 1980). The harbour porpoise is one of the small cetaceans most affected by human activities, and is now the subject of a great number of studies to determine the causes of its decline in some seas, and to attempt to evaluate its current status. Research carried out in the Baltic and North Seas (FAO, 1978; Kroger, 1986), as well as in the Black Sea (Smith, 1976; IWC, 1983) have revealed that the populations of this species are experiencing a serious decline. Ellis (1983) considers that practically all harbour porpoise populations are currently in serious decline. 1. POLLUTION 1.1 Organochlorines In recent years, research has revealed an alarming trend in the circulation and accumulation of polychlorinated biphenyls (PCBs) and related organochlorine compounds in the oceans of the world. One consequence of particular concern is that marine mammals, as top predators, ingest relatively large amounts of these compounds, which are concentrated as they pass along the food chain. Although, by their very nature, marine mammals are difficult to study, evidence that they are being severely, and possibly irreversibly, impacted by these substances is growing. Furthermore, it is predicted that the impact already reported is going to become widespread. PCBs can be taken as a good example of persistent, fat-soluble, ubiquitous environmental contaminants and, to a large extent, this review will focus on them. It should be noted, however, that these are only one family of marine contaminants and that other man-made chemicals may be contributing as much, if not more, to environmental problems. The fact that PCBs have been studied in recent years makes them a group of chemicals on which information is already available (Johnston and Simmonds, 1990). Their position at the top of the food chain means that dolphins have persistent chemicals passed to them via a series of accumulative steps. Organochlorine compounds entering the marine environment are typically hydrophobic and become associated with particles or plankton in the water. These are ingested by larger organisms which, in turn, are eaten by fish. At each step in the food chain the amounts of contaminants accumulated are concentrated. Concentrations of organochlorines reached in dolphins are thousands, if not millions, of times higher than those found in the surrounding sea water (see Table 1). Moreover, marine mammal blubber, a fat store, is an ideal site for the accumulation of large quantities of lipophilic (fat soluble) chemicals such as PCBs, DDT and others. It is not, however, simply an inert store and there is believed to be continual exchange of chemicals between the blubber and the blood circulating through the body (Reijnders, 1980). This process is greatly accelerated at times when the animal is unable to feed and has to use its stored lipids, or when a female is lactating. Indeed, vast quantities of contaminants may well be passed by marine mammals in the milk to their young. Lactation allows females to shed an important proportion of contaminants which they accumulated prior to giving birth. Recent studies indicate that as much as 80 to 90% of contaminant residues in adult female dolphins may be passed to their first born calf (Tanabe, 1988: Cockcroft et al., 1989). Recent research also indicates that marine mammals lack certain enzymes which may help terrestrial mammals to counteract PCB exposure to some extent (Tanabe, 1988 and Tanabe et al., 1988). This would make them more susceptible to the effects of contaminants and may relate directly to specific reproductive disorders already reported in some marine mammal populations. Three main lines of research have exposed the correlation existing between the presence of contaminants and observable effects in marine mammals. One was carried out on the effects of PCBs and DDT on the reproductive abilities of pinnipeds (Reijnders, 1980). Reproductive disorders, such as abortions and pathological changes in the uterus have been observed in Californian sea lions (Zalophus californianus), Baltic ringed seals (Phoca hispida) and, more recently, in grey seals (Halichoerus grypus) living in the highly polluted waters of Mersey Bay in the U.K. (Baker, 1989). Harbour seals (Phoca vitulina) in the Wadden Sea do not show the same uterine pathology but their reproduction is known to also be impaired. In an experimental study, seals fed on highly PCB-contaminated fish were found to have reduced reproductive success, and other disorders which could lead to immuno-suppression (Brouwer et al., 1989). Another area of pertinent research has focused on the declining population of belugas (Delphinapterus leucas) in Saint Lawrence Estuary. Martineau et al. (1987) concluded that organochlorine contamination should be considered as a prime cause for low recruitment observed within this population. There is ample evidence in the literature of PCBs being strong immunosuppressive agents (Safe, 1984), which may also contribute to mortality. Studies on other small cetaceans have been carried out by Japanese scientists. They found a negative correlation existing between PCB and DDT levels in the tissues of Dall's porpoises (Phocaenoides dalli) in the North-west Pacific and levels of testosterone (male hormone) (Subramian et al., 1987). This could well affect the reproductive vigour of male porpoises. Abnormalities in lipid metabolism, such as fatty livers, have also been detected in wild Japanese striped dolphins with high PCB and DDT levels in their tissues (Kawai et al., 1988). Cockcroft et al. (1989) accepted that mortality of first born South African bottlenose dolphin calves could be caused by high contaminant concentrations in their mother's milk. 1.2 Heavy Metals and Other Pollutants Organochlorine compounds reach the highest concentrations, but metal pollution is also present in high amounts in dolphins. These contaminants have been found in the kidney, liver, blubber, muscle, skin, lung and brain tissue (Viale, 1978). Some metals are bioaccumulated by cetaceans as they are unable to excrete them. Different processes taking place in the dolphins metabolism bind lead, mercury and selenium in non biodegradable compounds. Heavy metal concentrations in cetaceans are higher than in other animals. Dolphin tissues examined from the Mediterranean contained iron concentrations 8 times in excess of the maximum allowed in human diet, and 1,500 times higher in the case of mercury (Viale, 1978). A high proportion of the total concentration of mercury in contaminated marine animals is found as methylmercury (Martoja and Berry, 1980). Levels of methylmercury, the most toxic form of this metal, found in dolphins stranded in the Tyrrhenian coast were considered to be of great concern (Carlini and Fabbri, 1990), (See Table 2.) 1.3 Other pollutants The effect of some other pollutants has hardly been studied, and their effect on small cetacean populations is largely unknown. Information is available only for isolated instances of oil contamination , based on dead animals found stranded on the shore with clear evidence of oiling. Particular attention has been paid to animals impregnated in oil or with oil residues in their buccal cavity or spiracle. Oil derived compounds, perhaps particularly the PAHs which also bioaccumulate in fatty tissues, are of considerable concern. The excessive local use of pesticides introduces large amounts of pollutants, including HCH, HCB, dieldrin, aldrin, etc...., into the Mediterranean Sea. These compounds are more volatile than PCBs and DDT, and are therefore present at lower concentrations in dolphins, especially those of pelagic lifestyle. Until now, only the direct effects of contaminants on small cetaceans have been contemplated, but these and other toxic compounds could also have an effect on the dolphins' prey, and on the ecosystem in general, by reducing its biological diversity and decreasing the food mass, thus indirectly affecting the cetacean fauna. 1.4 Marine mammal mass mortalities. While the role played by pollution in mass mortalities is likely to remain controversial, considerable concern has been voiced that contaminants could be contributing to the major die-offs which have been witnessed in the last few years (see Harwood and Reijnders, 1988; Simmonds and Johston, 1989; Simmonds, 1991). Since 1987, five major marine mammal mortalities, affecting seals and dolphins, have taken place. The most recent of these has affected the striped dolphin (Stenella coeruleoalba) population of the western Mediterranean. Dead and dying dolphins started to appear on beaches near Valencia in early July 1990. Since then, hundreds of dead bodies have been found along the Spanish, French and Italian coasts, and on the North African shores opposite. Only a small proportion of the affected animals are thought to have stranded and a full death toll may be several thousand (Aguilar and Raga, 1990). Although pathogens have clearly been the trigger for some of these mortalities and epidemics have been known to occur in wild marine mammal populations before, the known immuno- suppressive effects of contaminants make it possible that they have contributed to the spread of these events. Immunosuppression could have encouraged the spread of infection. This and the additional chronic effects of organochlorines could hinder, or even prevent, recovery of individuals. Moreover, the effects of contaminants on reproductive systems could further hinder population recovery following mass mortalities. Table 1 ----------------------------------------------------------------- Levels of organochlorine contaminants in the adipose tissue of small cetaceans in the Mediterranean. ----------------------------------------------------------------- (ppm lipid basis) Spp Place NO. Year ppDDE ppTDE opDDT ppDDT tDDT PCB Ref. D.d France 1 1977 75 27 324 426 700 (1) D.d Catalo. 1 1978 650 147 7 31 835 2090 (2) D.d Catalo. 1 1987 23 5 8 36 92 (2) (biopsy) S.c. France 4 1973-77 264 23 62 349 367 (3) S.c. France 16 455 455 260 (4) S.c. Catalo. 1 1977-79 170 237 (5) S.c. Catalo. 17 1984-87 247 26 32 44 349 367 (2) S.c. Catalo. 78 1987-88 112 15 17 22 166 326 (2) (biopsy) S.c. Catalo. 5 1989 408 43 32 24 507 1320 (2) S.c. Catalo. 10 1989 78 8 12 17 115 237 (2) T.t. Italia 2 1975 96 34 22 49 201 384 (2) T.t. Castell. 1 1978 266 66 63 153 548 892 (2) T.t. Catalo. 1 1979 100 36 23 44 203 387 (2) T.t. Catalo. 3 1980 150 165 (5) T.t. Catalo. 1 1982 51 11 7 21 90 156 (2) T.t. Catalo. 1 1985 137 31 9 26 203 609 (2) T.t. Catalo. 1 1985 42 28 5 12 87 581 (2) (biopsy) T.t. Valencia 2 1988 164 12 8 13 197 490 (2) T.t. Catalo. 1 1989 222 30 32 28 312 950 (2) G.g. Catalo. 1 1978 133 294 (5) G.g. Catalo. 1 1984 296 106 5 12 419 790 (2) (calf) Z.c. Catalo. 1 1979 23 36 (6) Z.c. Catalo. 1 1985 58 16 8 30 112 200 (2) Z.c. Catalo. 1 1989 33 12 3 3 51 98 (2) M.d. Catalo. 1 1981 2.87 3.47 1.52 4.72 12.58 5.49 (5) P.m. Catalo. 1 1974 133 294 (5) ----- Catalo. = Catalonia Castell. = Castellon Table 2 ----------------------------------------------------------------- Levels of heavy metals in Mediterranean dolphins ----------------------------------------------------------------- ppm fresh weight basis. Sp No. Tissue Fe Ti Cr V Hg Pb Cd Se Ref. D.d 2 various- 22 0.12 0.04 0.02 5.30 0.16 0.01 (1) +380 1.60 0.30 0.10 604 0.21 1.21 S.c. 2 various- 20 0.50 0.05 1.57 (1) +280 2.83 S.c. 7 liver - 200 60 (2) + 2250 770 S.c. 6 kidney - 42 20 (2) + 200 94 T.t. 4 various-13.6 0.05 0.07 0.01 0.67 0.23 0.03 (1) +669 7.30 1.04 2.12 14.60 4.25 2.22 Z.c. 4 various-28.3 0.10 0.25 0.20 1.60 0.03 0.02 (1) +174 2.65 2.50 3.30 440 8.53 28.37 Z.c. 1 liver 1343 477 (3) P.m. 1 various- 18 0.30 0.40 0.30 0.65 0.08 0.02 (1) +204 3.16 1.05 2.04 3.70 10.15 28.73 ----------------------------------------------------------------- D.d. Delphinus delphis; S.c. Stenella coeruleoalba; T.t. Tursiops truncatus; G.g. Grampus griseus; Z.c. Ziphius cavirostris; M.d. Mesoplodon densirostris; P.m. Physeter macrocephalus Organochlorines (1) Vicente and Chabert, 1978. (2) Aguilar and Borrell, not published (3) Alzieu and Duguy, 1978. (4) Alzieu and Duguy, 1979. (5) Aguilar, 1983. (6) Aguilar, Jover & Nadal, 1982. Heavy metals (1) D. Viale, 1978 (2) Y. Thibaud, 1978 (3) R. Martoja & J. P. Berry, 1980. 2. DIRECT AND INCIDENTAL CATCHES 2.1 Driftnets Although the use of driftnets on a large scale in the Mediterranean started back in the late seventies, their use has only really become common over the last few years. At present, some one thousand fishing vessels are known to use driftnets (CFCM/ICCAT, 1990). Although driftnets are supposed to target specific species, such as swordfish and tunids, their inherent non-selectivity (they entangle any creature which is larger than the mesh size) causes very high mortality of non-target fish and marine animal species, such as sea turtles and cetaceans. The largest driftnet fleet in the Mediterranean is Italian, with over 900 vessels which use nets between 3 and 40 kilometres in length, averaging 14 km per vessel (Di Natale and Mangano, 1990). Cetacean captures are subject to variation, both in numbers and species, according to fishing grounds and seasons . The Italian vessels normally fish between the southern Tirrhenian Sea in April and the Ligurian Sea in October. From August to September 1988 the capture of 37 cetaceans by driftnets was recorded in the Ligurian sea, of which 29 died and 8 were released (Podesta and Magnaghi, 1989). In another study carried out between 1986 and 1988 in Italy, the capture of 150 cetaceans was recorded: 24 sperm whales (Physeter macrocephalus), 2 goose-beaked whales (Ziphius cavirostris), 10 pilot whales (Globicephala melas), 5 Risso's dolphins (Grampus griseus), 13 bottlenose dolphins (Tursiops truncatus), 68 striped dolphins (Stenella coeruleoalba) and 28 others were unidentified (Notarbartolo de Sciara, 1989). As Di Natale (1989) reports, in 1988 12 individuals were also disentangled from driftnets: 7 sperm whales, 4 pilot whales and one fin whale (Balaenoptera physalus). Nortarbartolo de Sciara's study, carried out over a three year period, is based on figures for stranded animals on Italian shores. This report records the number of stranded animals entangled in nets or with signs of injury caused by these nets. It must, however, be noted that most captured animals do not reach the shores (Di Natale, 1990) and are lost at sea, or sunk by fishermen who weigh the animals down with heavy objects such as rocks and batteries in an effort to reduce the number of stranded animals. It is estimated that thousands of cetaceans fall victim to these nets each year (Di Natale, 1990). In the case of some populations, like the sperm whales, it is believed that the use of these nets could drive them to extinction in the Mediterranean Sea (Notarbartolo Di Sciara, 1989). In 1985 a study was carried out on 67 recorded cases of strandings and captures of sperm whales in Italian waters, in an attempt to determine their cause. Conclusions were reached for 46 cases, and driftnets were established as the cause in 30 of them (Di Natale and Mangano, 1985). Three sperm whales were also found entangled in driftnets around the French coast in September 1988 (Maigret, 1989). Cetaceans have also been found entangled in driftnets off North Africa. Ktari-Chakroun (1980) points out the sighting at sea of a group of 10 minke whales (Balaenoptera acutorostrata), of which 4 were trapped in driftnets targetting swordfish. Despite efforts made by the Italian government to reduce the length of these nets, between April and June 1990 the capture of 3 sperm whales, 1 fin whale, 1 goose-beaked whale and about 20 small cetaceans in the Southern Tirrhenian Sea was recorded. A decree was laid down in Italy in late July, banning the use and possession of driftnets for the capture of swordfish. Nevertheless, it is feared that some fishing vessels may seek protection in other Mediterranean harbours or sell their nets to those countries currently beginning to use this type of fishing gear. According to a report by Lilly Venizelos, coordinator of the Meddaset Project in Greece, 50 Italian driftnetters have been seen fishing in the Aegean and Ionic Seas in 1991, causing the death of dolphins and sea turtles. The Spanish fleet has some 40 vessels fishing in the area around the Straits of Gibraltar. All these vessels hold Moroccan fishing licences, obtained through a fisheries agreement between the EEC and Morocco signed in 1988. Most of these vessels fish in the Atlantic area, close to Cape Espartel, although an unknown number occasionally also fishes in Mediterranean waters (south of Cape Gata). The Straits of Gibraltar are the sole route of access for cetaceans and other marine animals entering the Mediterranean Sea from the Atlantic Ocean. It is also believed that some fin whales may come into the Mediterranean on their winter migration (Viale, 1981). Recent studies in this area reveal the importance of this geographical area for certain cetacean populations, like the common dolphin (Delphinus delphis) and, to a lesser extent, the striped dolphin, believed to use the area as feeding grounds (Adloff, 1990). Resident populations of other cetaceans, such as the bottlenose dolphin, are also thought to exist here. In addition to the Spanish fleet, there are also over 40 Moroccan vessels using driftnets. Cost-benefit ratios are better for driftnets than for surface long-liners (no bait is required, captures per unit effort are larger, etc.) For this reason, the risks posed by the increased use in this type of fishing net in the Mediterranean has to be taken into account, as recent figures indicate that the fleet is increasing. This increase was discussed at the GFCM/ICCAT (1990) meeting on estimates of pelagic fish stocks in the Mediterranean, held in Bari (Italy) last June. Representatives of several countries expressed their concern about the increase. According to figures presented at this meeting, the vessels using this type of net are: Italy, 900; Spain, 43; France, 1; Morocco, 40; Greece, 13; Turkey, 13 and Algeria 1. 2.2 Other Fishing Gear The lack of information regarding incidental cetacean captures by artisanal fishing fleets and the high diversity of local fishing methods make it impossible to determine which species are the worst affected. In any case, it should be noted that most fishing methods and tackles create their own particular impact on cetacean populations, to varying degrees depending on the type of fishing method used and the ecology and behaviour of these marine mammals. Several published papers describe incidental captures by trammel nets, trawling nets, longlines and purse seine nets (Duguy et al, 1983; Di Natale, 1989), and the impact which fishing activities in general can have on cetacean populations in certain geographical regions (M'Hamed el Bouali, 1987). --------------------------------------------------- Interactions between cetaceans and fishing methods --------------------------------------------------- tramell purse-seine longlines trawler nets nets nets ----------------------------------------------------------------- S. coerulealba yes yes yes yes D. delphis yes yes yes yes T. truncatus yes yes G. griseus yes yes G. melas yes P. macrocephalus yes yes P. crassidens yes Although the most common instances of interactions known are those between the species and fishing methods indicated above, other cases of interactions between tuna traps (Di Natale, 1983; Ktari-Chakroun, 1980) and other less common fishing methods in the Mediterranean, and killer whales (Orcinus orca), bottlenose dolphins (Tursiops truncatus) and even one minke whale have occurred. (Ktari-chakroun, 1980) Based on studies carried out by the General Fisheries Council for the Mediterranean, the Review of the States of World Fish Resources (FAO, 1981a) states that demersal stocks of the northern and western shores of the Mediterranean, as well as some pelagic stocks, are already overexploited. It seems reasonable to consider the depletion of stocks of captured species as having a direct impact upon some marine mammal populations (Northridge, 1984). In addition, lack of food could lead to increased interactions between cetaceans and fishing activities, with the resulting risk to these marine mammals, considered by certain fishermen as "competitors" for a relatively scarce resource of high commercial value. Overfishing of prey species could also lead to malnutrition and associated problems in dolphins. 2.3 Direct catches Despite international agreements signed by many Mediterranean countries (Berne Convention, Bonn Convention, CITES, etc), and national laws in some of these, cetacean mortality is an established fact in practically every Mediterranean coastal country. These deaths are the result of interactions with fishing activities, commercialization of cetacean meat and blubber, the use of cetacean meat as fishing bait and deliberate slaughter of individuals. In certain countries, such as Malta, where interaction with the artisanal fishing fleet is high, fishermen often kill large numbers of cetaceans. This practice is actually fairly commonplace throughout the Mediterranean. Every year, dozens of dolphins are stranded on the shores with cuts, gashes or bullet wounds, caused mostly by fishermen in an effort to protect their fishing gear. In France alone, it is estimated that thousands of cetaceans die each year for these reasons (Duguy and Husenot, 1982). In Italy, between 1986 and 1987, 22 cetaceans were found stranded with evidence of bullet or harpoon wounds (Centro de Studi di Cetacei, 1987). 12 of them had had their dorsal muscular area removed, to be sold as food. Dolphin-hunting is known to have increased recently, and dolphin meat is sold to fishmongers and restaurants, particularly in Lazio, Toscana, Liguria and Sardinia. In Arbatax harbour there is talk of a small number of vessels carrying out this practice, while in Puerto S. Estefano (Tuscany) it seems that around 4 vessels capture dolphins as a side activity. Dolphin meat has been found in at least two restaurants and several food stores in the area. There are also cases of sale and consumer use of dolphin meat in Spain, and several fishermen have admitted to capturing these animals for salting and selling. Several vessels capturing small cetaceans for use as bait are known to exist in harbours of Andalusia and Murcia. This bait is used in deep sea longlining and crustacean fishing. Its smell and texture make it a favourite in the shrimp fishery. It seems that none of these vessels are exclusively dedicated to these particular captures but some fishermen are more efficient than others at later selling the meat for bait. It can therefore be stated that directed takes of cetaceans by fishermen in the Mediterranean are fairly commonplace and concerns must also be voiced about occasional shootings of cetaceans from recreational vessels as a sport. 2.4 The Black Sea Small cetacean kills in the Black Sea have occurred for at least the last hundred years, with the highest kills occurring in the last fifty years. The target species in this operation have been the harbour porpoise, the bottlenose dolphin and the common dolphin. The hunt, which also took place in the Azov Sea, was carried out primarily by Turkey and the USSR, but also by Bulgaria and Romania. The number of captures increased dramatically in the course of this century, and while in 1927 the total number of captures recorded was 9,300, this figure had increased to 135,000 by 1937 (Smith, 1976). The annual number of captures during the 1930's and 1940's was approximately as follows: USSR: 75,000; Turkey: 40,000; Bulgaria: 3,000 and Romania: 5,000 (Mitchell, 1975). The dolphins were caught by herding small schools together. These groups were then led to the fishing fleets, where fishermen set their nets around them. It has been noted that up to 2,500 porpoises were caught at one time during just one of these operations (Tomilin, 1957). On other occasions, fire arms were used to shoot the dolphins. These arms were purchased by fishermen with funds given by the Turkish government, and dolphins and porpoises were shot in the name of fisheries protection. From 1937 onwards, fisheries targetting these animals declined. The USSRhad to reduce its take and, from 1962, only deliberately captured porpoises and dolphins in the summer. In 1967, Soviets and Bulgarians abandoned the hunt and banned the killing of small cetaceans in their waters. The Romanians followed suite, while Turkey, which was the last to abandon this practice, maintained it until 1983. Turkey captured more than 176,000 animals in 1973, and it is thought that captures may have reached 332,000 animals in 1969 (Berkes, 1977). The volume of captures of small cetaceans from 1967 onwards ranged between 56,000 and 220,000 individuals per year (IWC, 1983). The three species targetted have experienced serious declines in population numbers. According to Smith (1976), the capture of these animals in the Black Sea appears to have reduced their abundance to marginal levels. 3. OTHER THREATS 3.1 Noise Cetaceans depend on sound for locating and identifying their prey and for communication. Increased boat traffic, industrial activity and oil drilling have brought noise to the aquatic environment, especially in waters near the coast. The effect of noise on cetaceans has been poorly studied, although it is generally accepted that the levels of noise usually associated with common human activities at sea are capable of interfering with signals produced by cetaceans in nearby waters or even causing damage to their sound receptors. Also, sustained exposure to even non-intense sound is known to produce stress-related effects which may lower resistance to disease and produce endocrine imbalances (Geraci and St.Aubin, 1980; Stirling and Calvert, 1983). 4. STATUS AND POPULATIONS 4.1 Ziphius cavirostris Common name: Cuvier's beaked whale Habitat: Typically pelagic Range: Throughout the Mediterranean Conservation: A shy species, avoids all contact with humans. Does not interact with the fisheries industry, except for a few isolated cases of accidental captures by driftnets. Contaminant levels in their tissues so far reported are comparatively low. 4.2 Delphinus delphis Common name: Common dolphin Habitat: Typically neritic, can be pelagic in some areas. Range: Throughout the Mediterranean and Black Seas. Conservation: Frequent instances of accidental captures by purse seiners off the coasts of southern Spain, southern Italy and northern Africa. They are also impacted by driftnets in every region where driftnets are used. Tissue contaminant levels are often very high. This species is very coastal in the Mediterranean, so is probably seriously impacted by the commercial overexploitation of the organisms it preys upon. In the northern section of the western basin (north of 39 degrees N) the species has apparently experienced a great decline and now its presence in the area is considered to be exceptional. In the Black Sea, the species has experienced a serious decline, due to direct captures by humans before 1983. Remarks: Determining the state of the common dolphin population in the Western Mediterranean is considered to be a priority by the "Action Plan for the Conservation of Biological Diversity of Dolphins, Porpoises and Whales. 1988-1992". The species is also included under section 22 of the Plan, emphasizing the need for research into its population status and the effect of the direct captures that took place in the Black Sea. 4.3 Stenella coeruleoalba Common name: Striped dolphin Habitat: Mostly pelagic, but also neritic in some areas close to the coast. Range: Throughout the Mediterranean. Conservation: This cetacean species is at present undoubtedly the most abundant in the Mediterranean. It has been suggested that it may have stepped into the ecological niche left by the common dolphin. Often falls prey to purse seine nets in southern Spain, southern Italy and northern Africa, and to driftnets in every area. The IWC/UNEP Workshop on the Mortality of Cetaceans in Passive Fishing Nets and Traps (La Jolla, October 1990) concluded that the population was "unable to sustain current levels" of incidental takes. Tissue contaminant levels, particularly PCBs, are extremely high, often in excess of 1,000 ppm. Diet is based on many fish and cephalopod species of economic importance, so fishing activities may seriously limit the growth of populations. In addition, this species has recently been struck by an epidemic of unknown origin, probably causing the death of several thousand individuals in the Western Mediterranean. Remarks: This species is included in section 23 of the "Action Plan for the Conservation of the Diversity of Dolphins, Porpoises and Whales. 1988-1992." 4.4 Tursiops truncatus Common name: Bottlenose dolphin Habitat: Typically coastal. No pelagic populations are known in the Mediterranean. Range: Throughout the Mediterranean and Black Seas. Conservation: Due to its coastal lifestyle, this species has been strongly impacted by human activities. Populations are currently fragmented into small units, surviving with difficulty in the areas where human impact is slightest. Interacts intensely with the fisheries industry, feeding on a large number of commercially important fish species and often destroying trammel nets, trawler nets and driftnets when taking fish. Mortality rates of this species are high, as it often gets trapped in nets. The IWC/UNEP Workshop on Mortality of Cetaceans in Passive Fishing Nets and Traps (La Jolla, October 1990) concluded that the current incidental take of the species "may not be sustainable". Fishermen react aggressively to the presence of bottlenose dolphins, shooting them with harpoons. Contaminant levels in the dolphins' tissues are very high, although lower than those found in common and striped dolphins. Remarks: This species is included in the recommendations for research on the Black Sea populations, under section 22 of the "Action Plan for the Conservation of the Diversity of Dolphins, Porpoises and Whales, (1988-1992)". 4.5. Orcinus orca Common name: Killer whale Habitat: Neritic and pelagic. Range: Most common in the western Mediterranean, but has been sighted occasionally in the southeast as well. Conservation: This species is not abundant in the Mediterranean, but is frequently sighted in the southern part of the Mediterranean and around the islands. Limited interaction with the tunids fishery, particularly tuna traps and purse seiners. There is no information available on the levels of chemical contaminants in their tissues, although they are assumed to be high as this species is a top predator and may even feed on other marine mammals. 4.6 Globicephala melas Common name: Long-finned pilot whale Habitat: Pelagic Range: Western Mediterranean, rarely in the east. Conservation : There are some isolated instances of accidental captures in different fishing gear with potential for impacting the population, and some individuals have been known to be affected by hydrocarbon spills. Contaminant levels in their tissues are relatively moderate. 4.7 Grampus griseus Common name: Risso's dolphin Habitat: Pelagic. Range: Western Mediterranean. Conservation: There are apparently some isolated instances of accidental captures in different fishing gear, and some individuals have been known to be affected by hydrocarbon spills. Contaminant levels in their tissues are moderate. 4.8 Steno bredanesis Common name: Rough-toothed dolphin Habitat: Pelagic. Range: Western Mediterranean. Very rarely seen in the east. Conservation : This species is rare in the Mediterranean Sea, and is thought to infrequently occur in every ocean. Fisheries interactions unknown. Contaminant levels in tissues unknown. 4.9 Phocoena phocoena Common name: Harbour porpoise Habitat: Neritic and pelagic Distribution: Black Sea Conservation problems: This species has experienced a serious decline in its population numbers due to direct captures by the fisheries industry in the Black sea. The species is very vulnerable to the effects of pollution, and is considered by the Council of Europe as "endangered by pollution". Remarks: The species is included in the research recommendations of the "Action Plan for the Conservation of the Diversity of Dolphins, Porpoises and Whales, (1988-1992)", under section 22. 4.10 Pseudorca crassidens Common name: False killer whale Habitat: Distribution: Throughout the Western Mediterranean Conservation problems: This species is rare in the Mediterranean and does not seem to pose any important conservation problems. Interactions with the fisheries fleets are minimal in the Mediterranean, due to the small population present in that sea. Contaminant levels in their tissues are unknown, but are assumed to be moderate. --------------------------------------- Cetacean species in the Mediterranean --------------------------------------- S.c. D.d. S.b. T.t. G.g. G.m. Z.c. O.o. P.c. ----------------------------------------------- ALBANIA No Yes No No No No No No No ALGERIA Yes Yes No Yes Yes Yes Yes Yes No CYPRUS Yes No No No No No No No No EGYPT Yes Yes No Yes No No Yes No Yes FRANCE Yes Yes Yes Yes Yes Yes Yes Yes Yes GREECE Yes Yes No Yes No No Yes No No ISRAEL No Yes Yes Yes No Yes Yes Yes No ITALY Yes Yes Yes Yes Yes Yes Yes Yes Yes LEBANON No No No Yes No No No Yes No LYBIA Yes No No Yes No No No No No MOROCCO Yes Yes No Yes Yes Yes Yes Yes No SPAIN Yes Yes No Yes Yes Yes Yes Yes Yes SYRIA No No No No No No No No No TUNISIA Yes Yes No Yes Yes Yes No No No TURKEY Yes Yes No Yes No No Yes No No YUGOSLAVIA No Yes No Yes Yes Yes No No No ----------------------------------------------- S.c. Stenella coeruleoalba; D.d. Delphinus delphis; S.b. Steno bredanensis; T.t. Tursiops truncatus; G.g. Grampus griseus; G.m. Globicephala melas; Z.c. Ziphius cavirostris; O.o. Orcinus orca; P.c. Pseudorca crassidens. The absence of species in any given country indicates only that data is not available, not that the species does not exist there. The species present in territorial waters around Monaco are not considered different from the ones found in French and Italian waters, given the small area in question. As for the Black Sea, the small cetacean species present there are found along the entire coastline. 5. CONCLUSIONS This report shows that while information collected so far does not suffice to give a complete view of the distribution and status of small cetacean populations in the Mediterranean, there is without doubt cause for grave concern. From the results of analyses carried out on tissue samples, it can be concluded that dolphins in the Mediterranean are amongst the animals most highly contaminated by PCBs in the world. Other toxic compounds such as DDT, and heavy metals like mercury, are also present in their tissues in very high concentrations. It is estimated that each year 120,000 tons of mineral oils, 12,000 tons of phenols (toxic, bioaccumulative organic compounds), 60,000 tons of detergents, 100 tons of mercury, 3,8000 tons of lead and 3,600 tons of phosphates are dumped into the Mediterranean by industrial, agricultural and urban activities (UNEP, 1984). In addition, over 600 tons of mercury, 150 tons of cyanide, 1,200 tons of PCBs, 3,000 tons of acids, 1,000 tons of solvents, 4,000 tons of paint sludge, 5,000 tons of pesticides and an unknown amount of heavy metals have accumulated on land (World Bank, 1990). The Mediterranean Sea is almost completely closed off, and it takes over a century for its waters to be replenished. This means that there is a great accumulation of toxic compounds, threatening the Mediterranean ecosystem and its fauna and flora. The build-up of contaminants weakens small cetaceans, making them more vulnerable to disease and reproductive problems. The only solution in the Mediterranean lies in halting all toxic discharges into the sea. The creation of a toxic discharge reduction plan for the Mediterranean Sea is urgently needed to halt its increasing contaminant concentrations. Some toxic compounds can persist between 50 and 120 years, during which they continue to act as highly hazardous agents. For example, mercury in water or in an animal metabolism forms methylmercury, highly toxic to all living organisms. Further information is needed to quantify the scope and frequency of cetacean interactions with the fishing industry, and must include research into measures to reduce the instances of accidental captures. Non-selective and destructive fishing gear such as large-scale driftnets should be banned in order to protect the biological diversity of the Mediterranean Sea and help prevent overfishing. As this report indicates, overexploitation of fish stocks can have a serious impact on cetacean populations, causing malnutrition and making them more vulnerable to viral, bacteriological or parasite infections. Fisheries overexploitation can also limit the recovery of different species due to the lack of food. Lack of food can intensify cetacean interactions with fishery activities and any measure taken to prevent overexploitation of fish stocks will benefit fishermen, dolphins and fishing resources alike. Intense maritime traffic in the Mediterraenan can also have an important impact on specific cetacean populations. In other seas, the presence of a large number of vessels in calving areas has been known to negatively affect the animals. The intensive use of some coastal areas as anchoring sites has degraded the sea bed, impacting the benthic fauna and therefore impacting the whole ecosystem. It is necessary to establish protected areas where productivity can be enhanced and small cetacean populations recover. Protection laws for small cetaceans should be laid down in every Mediterranean coastal country, banning the capture, killing, injury, trade and use as food or bait of cetaceans. The objective of such measures would be to protect Mediterranean biological diversity, and prevent cetaceans being used for food, noting that their high contaminant levels makes them unsuitable for that purpose. REFERENCES - Adloff B., Observations on dolphins off Europa Point, Gibraltar. Report of the Forth Anual Conference of the European Cetacean Society, 1990 - Aguilar A., Spain. Progress Report on Cetacean Research. June 1981 to May 1982. Report International Whaling Commision, 33, 1983. - Aguilar A., A record of two humpback whales, Megaptera novaeangliae, in the Mediterranean Sea. Marine Mammal Science, 5(3). 1989. - Aguilar A., Jover L., and Nadal J., A note on the organochlorine contamination in a Blainville's beaked whale, Mesoplodon densirostris, from de Mediterranean Sea. Dept. Zool. Barcelona, 7: 85-90, 1982. - Aguilar A., and J.A. Raga, Mortandad de delfines en el Mediterraneo. Poltica cientifica. 25, 51-54. 1990. - Alegria V., Tuna Fishing in the Eastern Adriatic, 1989. - Alzieu Cl., and Duguy R., Contamination du dauphin bleu et blanc de Mediterranee, Stenella coeruleoalba, par les composes organochlores. Antalya, CIESM, 1978. - Alzieu Cl., and Duguy R., Teneurs en composes organochlores chez les Cetaces et Pinnipedes frequentant les cotes francaises. Oceanologica Acta, 2, 1, 1979. - Annual Report by Centro Studi Cetacei, referred to the Cetacean Stranded in Italy, 1985-89. - Baker J.R., Pollution-associated uterine lesions in grey seals from Liverpool Bay area of the Irish Sea. Veterinary Record 125. 1989. - Barcelo F., Apuntes para la fauna balear. Anales R.Soc.Esp.His.Nat.,4. 1875. - Berkes F., Turkish dolphin fisheries. Oryx 14(2). 1977. - Boutiba Z., Repartition et frequence des echouages des cetaces sur le littoral ouest Algerien, 1989. - Brower A., Reijnders P.J.H., and Koeman J.H., Polychlorinated biphenyl (PCB) contaminated fisn induces vitamin A and thyroid hormone deficiency in the common seal (Phoca vitulina). Aquatic Toxicology 15, 1989. - Carlini R., and Fabbri F., Indagine preliminaire sul contenuto in mercurio e selenio in Odontoceti spiaggiati lungo le coste italiane, 1990. - Casinos A., and Filella S., Notes on Cetacean of the Iberian Coast: IV, A specimen of Mesoplodon densirostris stranded on the Spanish Mediterranean Littoral, 1975. Saugetier Kundliche Mitteilungen, 4, 1981. - Casinos A., and Vericad J. R., The Cetaceans of Spanish Coast; a survey, 1976. - Casinos A., Los Cetaceos del Mediterraneo. Mundo Cientifico, 19, 2, 1982. - CFCM/ICCAT, Draft Report of the Meeting of Experts - Consultation and Evaluation of Stocks of Large Pelagic Fishes in the Mediterranean Sea. Bari, Italy, 1990. 21-27 June 1990. - Centro Studi Cetacei, Annual Report referred to the Cetacean Stranded in Italy, 1987. - Centro Studi Cetacei, Annual Report referred to the Cetacean Stranded in Italy, 1988. - Cockcroft V.G., De Kock A.C., Lord D.A., and Ross G.J.B., Organochlorines in bottlenose dolphins (Tursiops truncatus) from the east coast of South Africa. S. Afr. J. Mar. Sci. 8, 1989. - Companyo L., Histoire Naturelle du Departement des Pyrenees Orientales, T III. 1863. - Cummins J.E., Extinction: The PCB threat to marine mammals. The Ecologist, 18(6), 1988. - Currey D., et al., The Global War Against Small Cetaceans, Environmental Investigation Agency, 1990. - Di Natale A., Striped dolphin in the Central Mediterranean Sea: An analysis of the new data. Rapp.P.V. Reun.CIESM, 28 (5): 201-2. 1983. - Di Natale A., Marine Mammal Interactions in Scombridae Fishery Activities: The Mediterranean Case, 1990. - Di Natale A., Rapporto sulla pesca in Italia. World Wildlife Fund. 1989. - Di Natale A., and Mangano A., Mare Nostrum, Bull. Central Institute for the Scientific Research applied to the Marine Fishery, I.C.R.A.P., 1990. - Di Natale A., and Mangano A., Proceeding of the First National Conference on Cetaceans. Riccione, Italy. 1985. - Dietz R., Heide-Jorgensen M.P., and Harkonen T., Mass deaths of harbor seals (Phoca vitulina) in Europe. Ambio 18(5), 1989. - Duguy R., Les Mammiferes Marins de la Mediterranee Occidentale, 1990. - Duguy R., et al., L'impact des activites humaines sur les cetaces de la Mediterranee occidentale. Rapp.P.-V. Reun.CIESM., 28(5):219-22. 1983. - Duguy R., Casinos A., Di Natale A., Filella S., Ktari Chakroun F., Lloze R., and Marchessaux. Repartition et Frequence des Mammiferes Marins en Mediterrane‚. Rapp.Comm.Int.Mer.Medit. 28, 1983. - Duguy R., and Husenot E., Occasional captures of delphinids in the Northeast Atlantic. Rep. Int. Whaling. Comm., (32): 461-2. 1982. - Duinker J.C., and Hillebrand M.Th.J., Mobilisation of organochlorines from female lipid tissue and trans placental transfer to fetus in a harbour porpoise (Phocoena phocoena) in a contaminated area, Bull. Environ, Contam, Toxicol. 23, 1979. - Ellis R., Dolphins and porpoises. Robert Hale Ltd., 1983. - FAO. Mammals in the sea. FAO Fisheries series No.5. Food and Agriculture Organization of the United Nations, 1978. - FAO, Examen de las situacon de los recursos pesqueros mundiales. FAO, Fish. Circ., (710). Rev. 2, 41 p. 1981a. - Focardi S., Marsili L., Fabbri F., and Carlini R., Preliminary Study of Chlorinated Hydrocarbon levels in Cetacea Stranded along the Tyrrhenian coast of Latium, 1990. - Geraci J.R., and St.Aubin D.J.,: Offshore petroleum resource development and marine mammals: a review and research recommendations. Marine Fisheries Review, 42, 1-12. 1980. - Graells M., Las ballenas de las costas oceanicas de Espana. Mem. R. Acad. Ciencias Exactas, Fisicas y Naturales, 23(3). 1889. - Harwood J., and Reijnders P., Seals, sense and sensibility. New Scientist 120, 1988. - Hershkovitz Ph., Catalog of living whales. US National Museum Bulletin, 246. 1966. - IWC. Report of the sub-committee on Small cetaceans. Document No. IWC/35/4, International Whaling Commission, 1983. - IWC/UNEP. Workshop on the Mortality of Cetaceans in Passive Fishing Nets and Traps. La Jolla, October 1990. - Johnston P.A., and Simmonds M., A brief overview of the health and environmental effects of PCBs. Submission to the Welsh Affairs Committee. House of Commons Paper 80. Unprinted annex 5. 12 pages, 1990. - Kawai S., Fukushima M., Miyazaki N., and Tatsukawa R., Relationship between lipid composition and organochlorine levels in striped dolphin. Marine Pollution Bulletin 19(3), 1988. - Kroger R.H.H., The decrease of harbour porpoise in the Baltic and North Sea. Final report on a Swedish-German project funded by the World Wildlife Fund In Sweden and Germany, and the Swedish National Environment Protection Board, 1986. - Ktari-Chakroun F., Les Cetaces des Cotes Tunisiennes, 1980. - Lavigne D.M., and Schmitz O.J., Global warming and increasing population densities: a precipitation for seal plagues. Marine Pollution Bulletin 21(6), 1990. - Maigret F., Cetaceans on Mediterranean French Coasts, First International Conference on Marine Mammals, Riccione (Italy) 1989. - Marquenie J.M., Assesing the environmental impacts from contaminated sediments in The Nethelands . Report to the sediment subcommittee of the Great Lakes Water Quality Board. Proceedings of the Technology Transfer Symposium for the Remediation of Contaminated Sediment In the Great Lakes Basin, 1990. - Martineau D., Beland P., Desjardins C., and Lagace A., Levels of organochlorine chemicals in tissues of beluga whales (Delphinapterus leucas) from St. Lawrence Estuary, Quebec, Canada. Arch. Environ. Contamin. Toxicol 16:137-147. 1987. - Martoja R., and Berry J. P., Identification of Tiemannite as a probable product of demethylation of mercury by selenium in cetaceans. A complement to the scheme of the biological cycle of mercury, Vieu Milieu, 1980. - Martorell J., Proyecto de Investigacion sobre actividades espanolas relacionadas con capturas de pequenos cetaceos, 1988. - M'Hamed el Bouali M., Les cetaces du litoral ouest algerien, 1987. - Miguel de la Serna J., and Alot E., Pesquerias espanolas de tunidos en el Mediterraneo, 1989. - Mitchell E.D., Porpoise, dolphin and small whale fisheries of the world. Status and problems. IUCN Monograph No.3, 1975. - Miyake P.M., Notes on the data base for the highly migratory species in the Mediterranean, 1989. - Northridge S.P., Estudio Mundial sobre las Interacciones entre Mamiferos Marinos y la Pesca. FAO inf.Pesca (251):234p. 1984. - Northridge S.P., et Pilleri G., A review of human impact on small cetaceans, 1986. - Notarbartolo di Sciara G., Tecnologie per la riduzione delle capture accidentali di cetacei nelle reti pelagiche derivanti: Stato dell'arte, 1989. - Notarbartolo di Sciara G., Cetacean incidental catch in the Italian driftnet swordfish fishery, 1986-1988. - Podesta M., and Magnaghi L., Unusual Number of Cetacean Bycatches in the Ligurian sea. Report of the third meeting of the European Cetacean Society, 1989. - Prescott J.H., and Fiorelli P.M., Report No.MMC-78/08 National Technical Information Service. U.S. Department of Commerce. Springfield. Va, 1980. - Reijnders P., Organochlorine and heavy metal residues in harbour seals from the Wadden Sea and their possible effects on reproduction. Netherlansa Journal of Sea Research 14(1), 1980. - Rey J.C., and Cendrero O., Les mammiferes marins trouves sur les cotes espagnoles en 1981, CIESM, 1982. - Safe S., Polychlorinated biphenyls (PCBs) and Polybrominated biphenyls (PBBs) Biochemistry, Toxicology and mechanism of action. C.R.C. Critical Review in Toxicology Vol.13(4). 319-395. 1984. - Simmonds M., What future for European seals now the epidemic is over?. Oryx 25(1) 1991. - Simmonds M., and Johnston P.A., Seals, sense and science. Marine Pollution Bulletin 20 (11), 1989. - Smith T.D., Current understanding of the status of small cetacean populations in the Black Sea. Mammals in the sea. Vol.4 FAO. Fisheries Service, 1976. - Stirling I., and Calvert W.,: Environmental threats to marine mammals in the Canadian arctic polar record, 21 (134): 433-449. 1983. - Subramanian A., Tanabe S., Tatsukawa R., Saito S., and Miyazaki N., Reduction in the testosterone levels by PCBs and DDE in Dall's porpoises of Northwestern North Pacific. Marine Pollution Bulletin 18(12). 1987. - Tanabe S., PCB problem in the future. Envir. Pollution, 50, 1988. - Tanabe S., et al., Capacity and mode of PCB metabolism in small cetaceans. Mar. Mamm. Sci. 4(2):103-144. 1988 - Thibaud Y., Presence simultanee de Mercure et de Selenium chez le dauphin, Stenella coeruleoalba, et le Thon rouge, Thunnus thynnus, de Mediterranee, Antalya, CIESM, 1978. - Tomilin A.G., Mammals of the U.S.S.R. and adjacent countries. Vol 9: Cetacea. Izdatel'stvo Akademi Nauk SSR, Moscow. 1957. - Troncone et al., The strandings of cetaceans along the coast of Puglia: Connections with fishing, 1990. - UNEP, Pollutants from land-bases sources in the Mediterranean. UNEP Regional Seas Reports and Studies No.32. 1984. - Viale D., Evidence of metal pollution in Cetacea of the Western Mediterranean, 1978. - Viale D., Ecologie des cetaces en Mediterranee occidentale. Mammals in the sea. Vol.3 Fao Fish.Ser. 1981. - Vicente N., and Chabert D., Recherches de polluants chimiques dans le tissu graisseux d'un dauphin echoue sur la cote mediterraneenne, Oceanologica Acta, 1, 3, 1978. - World Bank, The Environmental Program for the Mediterranean. Preserving a Shared Heritage and Managing a Commom Resource, World Bank, 19??