The possibility of persistent pollutants playing an adverse role in the reproductive success of Audouin's Gull in the western Mediterranean was examined through chemical analyses of 7 eggs of this species that did not hatch. Residues of organochlorine compounds and mercury were found. The conclusion has been reached that a further increase of present levels of DDE may well lead to a decline of the reproductive success of the species in the western Mediterranean, especially in the northern part. These observations, although limited, could have implications for further species as is already indicated by other work cite

Bijleveld, M. F. I. J.

Goeldlin, P.

Mayol, J.

渡邉, 雅弘

2746

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翻訳と註解 ディオゲネス・ラエルティオス第10巻(1)―エピクロスの巻―

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Persistent Pollutants in Audouin's Gull {Larus audouinii) in the WesternMediterranean: A Case-study with Wide Implications?byM. F. I. J. BIJLEVELD, Ph.D. (Amsterdam Free University)Programme Officer, IUCN, 1110 Morges, Switzerland,P. GOELDLIN, Ph.D. (Lausanne)Zoological Museum, Lausanne, Switzerland,&J. MAYOLGrupo Ornitologia Balear, Palma de Mallorca, Spain.INTRODUCTIONThe world population of the rare and specializedAudouin's Gull {Larus audouinii) is restricted to theMediterranean region (Voous, 1960) and is now esti-mated to number only about 2,000 pairs, of which thewestern Mediterranean harbours some 80%. Although anincrease appears to have occurred in the latter area inrecent years (Mayol, 1978), the species is rightly includedin the IUCN Red Data Book (Figs. 1 & 2).In 1978 a survey of the species was carried out in theframework of project No. 1413 in the conservation pro-gramme of the International Union for Conservation ofNature and Natural Resources (IUCN), the World Wild-life Fund (WWF), and the International Council for BirdPreservation (ICBP). During this survey, some eggs thathad not hatched were collected and their contents wereanalysed at the Cantonal Laboratory of the Canton deVaud, Epalinges, Switzerland. The shells have been de-posited in the Zoological Museum, Lausanne.METHODSThree of the unhatched eggs of Audouin's Gull werecollected in the southern Mediterranean region off theFig. 1. Adult Audouin 's Gulls (Larus audouinii). Total length (tip of bill to tail) 49 cm. Photo: Helmar Schenk.139Environmental Conservation, Vol. 6, No. 2, Summer 1979—©1979 The Foundation for Environmental Conservation—Printed in Switzerland.https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0376892900002642Downloaded from https:/www.cambridge.org/core. University of Basel Library, on 11 Jul 2017 at 12:15:01, subject to the Cambridge Core terms of use, available at140 Environmental ConservationFig. 2. Flock of adult Audouin's Gulls on an island off the coastof Morocco. Photo: Joan Mayol.Moroccan coast, the other four being collected in thenorthern Mediterranean—in the Balearic Islands, wherealso were collected one unhatched egg each of the Medi-terranean Herring Gull (Lams argentatus michahellis)and the Black Vulture (Aegypiusmonachus). Only addledeggs that had failed to hatch were taken, and thereforethese do not constitute an unbiased sample.The qualitative and quantitative analyses of organo-chlorine insecticide and polychlorobiphenyl residueshave been accomplished through:a) Extraction from samples by employing themethod of Langlois etal. (1964);b) Clean-up of the extracts by absorptive chroma-tography on a column of florisil; andc) Determination of the residues by gas chromato-graphy on two columns of different polarities employingelectron capture detection.The determination of total mercury was carried outby flameless atomic absorption spectrophotometry (cold-vapour system).RESULTS AND DISCUSSIONThe results of the analyses are presented in Table I.Chemicals detected included mercury, DDE (dichloro-phenyl-dichloroethylene), PCBs (polychlorinated bi-phenyls), HCB (hexachlorobenzene), dieldrin, and HE(heptachlor-epoxide). On average, levels were lowest fordieldrin, heptachlor-epoxide, and hexachlorobenzene.The difference between average levels of DDE, PCBs,and mercury, in Audouin's Gulls in the northern andsouthern parts of the western Mediterranean, is striking.DDE levels averaged from 1.94 ppm in the south to3.67 ppm in the north.A strong correlation was found between the amountof DDE (metabolite of DDT) in eggs with reproductivesuccess or decline of the Brown Pelican (Pelecanusoccidentalis) in South Carolina (Blus et al, 1974).Reproductive success was normal in those nests in whichsample eggs contained 2.5 ppm DDE or less, while inthose with eggs exceeding that level no downy youngwere produced (Ibid.). Similar relationships were foundin Ospreys (Pandion haliaetus) in Connecticut at averagelevels of 8.9 ppm DDE in sample eggs, whereas Ospreysin Maryland hatched normally at an average level of2.4 ppm DDE in sample eggs (Wiemeyer etal, 1975).Lincer (1975) came to similar conclusions with regard tothe American Kestrel (Falco sparverius). Koeman et al.(1972) concluded that DDE was most likely to be themajor cause of the lack of reproductive success in SeaEagles (Haliaetus albicilla) in Schleswig-Holstein, Fed-eral Republic of Germany, where an average of 10.12ppm DDE has been found in eggs that did not hatch.The average levels of pollutants found in the southernpart of the western Mediterranean region still seem tofall within the range where normal reproduction can beexpected (cf. Figs. 3 & 4).Although the failures of hatching may have resultedfrom disturbance or some other cause, the average levelfound—especially in the north of the western Mediter-ranean, where maximum levels reach 4.15 ppm and 5.44ppm—give reason for concern as they approach, or havealready reached, the level where only diminished repro-duction can take place. In this context, the fact that twoof the sample eggs from the northern Mediterranean con-tained embryos may have some significance (cf. Blusetal, 1974).Average levels of PCBs also appear to be much higherin the northern than in the southern part of the westernFig. 3. Nest and eggs of Audouin's Gull (Larus audouinii) on aBalearic island. Eggs approx. 62 X 43 mm. Photo: Joan Mayol.Fig. 4. Audouin's Gulls (Larus audouinii) in first-year plumage.These specimens are not yet fully grown. Photo: Xese Moll.https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0376892900002642Downloaded from https:/www.cambridge.org/core. University of Basel Library, on 11 Jul 2017 at 12:15:01, subject to the Cambridge Core terms of use, available atBijleveld et al.: Persistent Pollutants in Audouin 's Gull (Larus audouinii) in the Western Mediterranean 141TABLE I. Residues of Organochlorine Pesticides, PCBs, and Mercury, in Eggs of Audouin's Gull, Herring Gull, andBlack Vulture, 1978.Species Collection area Residue concentration ppm (net-weight)DDE Dieldrin HE HCB PCB HgRemarksLarus audouiniiLarus audouiniiLarus audouiniiChafarinas IslandsChafarinas IslandsChafarinas IslandsAverage1.021.952.840.0460.0780.050tr.*0.013ndt1.94 0.0580.0280.0340.0270.0303.14.24.20.700.630.953.82 0.76Larus audouiniiLarus audouiniiLarus audouiniiLarus audouiniiBalearic IslandsBalearic IslandsBalearic IslandsBalearic Islands2.205.442.904.150.1040.1380.1300.1200.031nd+0.0290.0230.0550.0850.1580.08012.820.616.017.60.871.001.391.22*tr. = trace. "I" nd = not determined.embryonatedembryonatedLarus argentatus subsp.Aegypius monachusmichahellisAverageBalearic IslandsBalearic Islands3.673.550.200.1230.062nd+0.0210.0070.0080.090.0530.01216.7511.00.4I10.12.20.15Mediterranean, being 16.75 ppm and 3.82 ppm, respec-tively. In general, however, there are no indications asyet that PCBs are involved in any reduction of reproduc-tion in birds. The levels found are relatively low in com-parison with some of those found for example in NorthGerman Sea Eagles (Koeman et al, 1972; Blus et al,1974).Dieldrin levels ranging from averages of 0.058 ppm inthe south to 0.123 ppm in the north can be regarded astoo" low to influence reproductive success. Blus et al.(1974) found that reproduction in the Brown Pelicanwas still normal in eggs containing <0.54 ppm of dieldrin.As could be expected, lower levels of mercury (average0.76 ppm) were found in the south of the western Medi-terranean than in the northern portion (1.12 ppm).However, these levels are not likely to influence repro-ductive success (J. H. Koeman, 1979 pers. comm).The levels of residues of organochlorine pesticidesfound in an egg of the Mediterranean Herring Gull in theBalearic Islands equal the average level of DDE found inthe eggs of Audouin's Gull, whilst levels of dieldrin,HE, HCB, and PCBs, are considerably lower—a fact thatmay be related to Audouin's Gull being more exclusivelya fish-eating species.The analysis of the contents of an unhatched egg ofthe Black Vulture from the Balearic Islands revealed ex-tremely low levels of all organochlorine compounds andof mercury. The hatching failure of this egg is thereforelikely to be due to other factors. The extreme differencesfound between levels in this terrestrial species and thetwo marine species, all of them placed at the end of food-chains, well illustrate the contamination of the marineenvironment.CONCLUSIONThe levels of DDE found in the eggs of Audouin'sGull, especially in the western Mediterranean, give reasonfor concern about the reproductive success of the species,which could be impeded by further contamination ofthis marine environment by DDT. These findings—thefirst that are known to us on marine birds' eggs in theMediterranean—complement similar findings of hifhlevels of organochlorine compounds in a wide variety ofspecies elsewhere in the Mediterranean (CIESM [Com-mission internationale pour l'exploration scientifique dela Mediterrane"e], 1979).ACKNOWLEDGEMENTSWe are indebted to Drs A. Etournaud and A. Ramuz,of the Cantonal Laboratory of the Canton de Vaud, forcarrying out the analyses, and to the World WildlifeFund, Switzerland, for making this financially possible.To Professor Dr J. H. Koeman, of the Agricultural Uni-versity, Wageningen, Netherlands, and to Dr P. Hunkeler,IUCN, Morges, Switzerland, we are grateful for theirhelpful advice given on reading an earlier draft of themanuscript.SUMMARYThe possibility of persistent pollutants playing anadverse role in the reproductive success of Audouin'sGull in the western Mediterranean was examined throughchemical analyses of 7 eggs of this species that did nothatch. Residues of organochlorine compounds and mer-cury were found.The conclusion has been reached that a further in-crease of present levels of DDE may well lead to a declineof the reproductive success of the species in the westernMediterranean, especially in the northern part. Theseobservations, although limited, could have implicationsfor further species as is already indicated by other workcited.https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0376892900002642Downloaded from https:/www.cambridge.org/core. University of Basel Library, on 11 Jul 2017 at 12:15:01, subject to the Cambridge Core terms of use, available at142 Environmental ConservationREFERENCESBLUS, L. J., NEELY, B. S., BELISLE, A. A. & PROUTY, R. M.(1974). Organochlorine residues in Brown Pelican eggs:Relation to reproductive success. Environ. Pollut., 7, pp.81-91.CIESM. (1979). IVesJournees d'Etude sur les Pollutions Marinesen Mediterranee. Workshop on Pollution of the Mediter-ranean, Antalya, 24-27 November 1978. Commission Inter-nationale pour l'exploration scientifique de la Mediter-ranee, Monaco: 681 pp.KOEMAN, J. H., HADDERINGH, R. H. & BIJLEVELD, M. F. I.J. (1972). Persistant pollutants in the White-tailed Eagle(Haliaetus albicilla) in the Federal Republic of Germany.Biol. Conser., 4 (5), pp. 373-7.LANGLOIS, B. E., STEMPAR, A. R. &'LISTA, B. J. (1964).Rapid clean-up of dairy products for analysis of chlorinatedinsecticide residue by electron capture gas chromatography.J. Agr. Food Chem., 12, p. 243.LINCER, J. L. (1975). DDE-induced eggshell-thinning in theAmerican Kestrel: A comparison of the field situation andlaboratory results./. Appl. Ecol, 12, pp. 781-93.MAYOL, J. (1978). Las Colonias de Gaviota de Audouin en elMediterraneo occidental en 1978. Stencilled report, IUCN,1110 Morges, Switzerland: 32 pp.VOOUS, K. H. (1960). Atlas of European Birds. Nelson, London,U.K.: 284 pp., illustr.WIEMEYER, S. N., SPITZER, P. R., KRANTZ, W. C, LAMONT,T. G. & CROMARTIE, E. (1975). Effects of environmentalpollutants on Connecticut and Maryland Ospreys. J. Wild!.Manage., 39 (1), pp. 124-39.International Effort to Study Causes of MonsoonsThe largest scientific venture ever undertaken jointlybetween the United States and South-east Asia has beenlaunched as part of a year-long effort to determine whatcauses the erratic behaviour of monsoons that are apt todevastate large areas of the world. One goal of the inter-national project is to hasten the day when scientists willbe able to forecast monsoons accurately—a capabilitywhich has been described as among mankind's most im-portant single predictions.The project, called 'MONEX' for monsoon experiment,was started on 1 December 1978 in Kuala Lumpur, thecapital of Malaysia. The US portion of the project isbeing coordinated by the National Science Foundation(NSF) and is considered a major expression of goodwillbetween the US and the South-east Asian countries wherethe winter phase of MONEX is being concentrated. OtherUS agencies taking part in the project are the NationalOceanic and Atmospheric Administration (NOAA) andthe National Aeronautics and Space Administration(NASA).Monsoons, which vary in time and intensity from yearto year, can bring life-giving rains or cause devastatingdroughts in South-east Asia and West Africa. They arethe basis for the rich agriculture of this vast region and amajor factor in the feeding of hundreds of millions ofpeople who inhabit the area. The improved forecastswhich may result from this project could be of specialbenefit to farmers and fishermen, enabling the former tomake suitable decisions on when to plant their seeds orto harvest their crops (e.g. avoiding inclement weatherconditions that could affect yields),* while the latterwould be able to plan their voyages on the open seas •with a minimum of risks of encountering bad storms.The behaviour of large-scale Asiatic monsoons islinked to global circulations which bring weather andpossibly weather anomalies to the United States. A betterknowledge of the Asian monsoon as a major regionalenergy source is essential to an improved understandingof global weather and climate. Extended forecasts overall areas of the world are probably not possible withoutdetailed knowledge of the weather in the tropics and itswide-ranging effects. In addition to the United Statesand Malaysia, almost every country in South-east Asia isparticipating in the project.Because of the natural division of the monsoon into awinter and a summer phase, and because of the regionaldistinctions in the monsoon between the eastern andWestern regions of Asia, two separate efforts are re-quired—a winter MONEX and a summer MONEX. Thesummer phase is scheduled to start on 1 May 1979 andto continue for four months, with its activities centredat New Delhi, India. Both efforts are designed to obtaina more comprehensive understanding of the regional andseasonal fluctuations of the Asian monsoon, and of itseffect on global atmospheric circulation, than has hithertobeen available.For these purposes, ships and aircraft will gather datafrom an area of some 74 million square kilometres overthe Indian Ocean, Arabian Sea, the Bay of Bengal, South-east Asia, and the South China Sea. In addition, MONEXscientists will get data from two geostationary weathersatellites, one of which is being provided earily in 1979over the Indian Ocean in a cooperative effort by theNSF, NOAA, and NASA, while the other has alreadybeen made operational to the south of Japan by theJapanese.MONEX is one of three regional experiments organizedwithin the framework of the Global Weather Experiment;the other two are the West African Monsoon Experimentand the Polar Experiment. The Global Weather Experi-ment, in which more than 140 nations are participating,is part of the Global Atmospheric Research Programme,a joint effort of the World Meteorological Organizationand the International Council of Scientific Unions. TheGlobal Weather Experiment is a year-long internationalprogramme of research and data-gathering whose ultimategoal is to make possible longer-range weather predictionsand to study the underlying causes of climate changes.Ralph KazarianNational Science Foundation1800 G StreetWashingtonDC. 20550USA.*A referee points out the importance here of 'policy on acqui-sition, storage, and import'.—Ed.https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0376892900002642Downloaded from https:/www.cambridge.org/core. University of Basel Library, on 11 Jul 2017 at 12:15:01, subject to the Cambridge Core terms of use, available at