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Behaviour and oil vulnerability of fulmars Fulmarus glacialis during an oil spill experiment in the Norwegian sea
Marine PollutionBulletin 0025-326X/93 $6.00+0.00 © 1993 Pergamon Press Lid
Marine Pollution Bulletin, Volume 26, No. 3, pp. 144 146, 1993. Printed in Great Britain.
Behaviour and Oil Vulnerability of Fulmars Fulmarus glacialis During an Oil Spill Experiment in the Norwegian Sea SVEIN-HAKON L O R E N T S E N and TYCHO ANKER-NILSSEN Norwegian Institute for Nature Research, Tungasletta 2, N-7005 Trondheim, Norway
The behaviour and oil vulnerability of Fulmars was studied when 30 t of crude oil was experimentally released at Haltenbanken, 150 km off the coast of Central Norway in July 1989. Evidence strongly suggests that the Fulmars deliberately avoided to settle on sea surface that was polluted with heavy oil. However, about 4% of the Fulmars in the area were slightly oiled, probably because they had been attracted to surrounding blueshine areas by food remains thrown overboard from the research vessel.
Impact assessments of oil pollution on seabirds worldwide have shown that it is necessary, beside having basic knowledge about population dynamics, to gain more exact knowledge on the behaviour of seabirds in relation to oil spills at sea as well as their risk of getting contaminated (Wiens et al., 1984). Such knowledge is essential to improve the validity of the different impact assessment models used (e.g. King & Sanger, 1979; Ford et al., 1982; Anker-Nilssen & Vader, in manuscript). It is particularly important to obtain reliable estimates of the proportions of birds in a spill area that will become oiled, and which factors that influence this parameter (e.g. species, age, sex, season, light, weather). Up to now, information about seabird behaviour in relation to oil spills has only been found in obscure publications and reports. Behavioural studies under otherwise natural conditions are, as far as we know, still scarce. During a full-scale experimental oil spill at Haltenbanken off Central Norway in July 1989 we conducted studies aimed at gathering information about Fulmar (Fulmarus glacialis) behaviour and vulnerability in relation to oil at sea. The Fulmar is normally the only seabird that occurs in any numbers in this area during summer (Norwegian Seabird Register, unpubl, data), probably mainly because the area is too distant for most seabirds breeding along the Norwegian coast. Materials and Methods
The oil spill experiment was carried out primarily to 144
study different methods of oil spill detection and tracking, but was also designed to investigate oil weathering and conflicts between oil and seabirds at sea. On 1 July 1989, 30 t of Oseberg crude oil was released at Haltenbanken (spill site 65°00'N, 08°00'E) about 150 km off the coast of Central Norway. The oil slick was followed for 5 days at which time most of the oil had either evaporated or dissolved into the water column. The spill site was chosen in advance according to drift model simulations which estimated the probability of oil reaching land within 5 days to be less than 1%. Permission to conduct the experiment was given by the Norwegian State Pollution Control Authority. Shortly after the release of oil and during the following day the numbers of Fulmars in different directions from the oil slick was recorded. The weather was good with calm sea and air temperatures above 10°C. The research vessel was located at the edge of the slick and two observers counted simultaneously all birds within an area of 300 x 300 m on each side of the boat during nine 10-min intervals, such that one always observed towards the slick while the other covered the opposite direction. These observations were restricted to periods when there were no other activities that could have influenced the distribution of birds. Birds lying on the sea surface and birds flying were treated separately. On 3-4 July heavy wind and waves followed by fog made similar observations impossible. To obtain data on the background contamination of Fulmars in the Haltenbanken area all birds observed before the experiment started (i.e. on 27 and 28 June) were checked for any oil contamination. Throughout the whole experiment (1-6 July) notes were made of Fulmar behaviour and of all oil contaminated birds observed. Results
Fulmar distribution in relation to the oil slick During the first 2 days of the experiment, the distribution of Fulmars on the sea surface and in air towards and from the oil slick was strikingly uneven (X z= 33.7, d f = l , p < 0.001, Table 1). Not a single bird
Volume 26/Number 3/March 1993 TABLE 1
Numbers of Fulmars (totals and 10-min interval means) flying above or lying on the sea surface in directions to and from the most heavily polluted part of the oil slick during the first 2 days of the oil spill. Observations were done simultaneously in both directions during nine 10-min intervals. The results of Chi-square tests (with Yates correction for continuity) are indicated. Behaviour
N
Flying On surface Chi-square
38 0
Towards slick Mean
SD
N
4.22 2.77 0.00 0.00 X2= 36.0 p < 0.001
42 57
was o b s e r v e d o n the sea surface in the sector facing the oil spill. In significant contrast to this, the m e d i a n n u m b e r of flying birds o b s e r v e d per 10-min interval was three in b o t h directions, as was the m e d i a n n u m b e r of birds lying o n the surface in the sector away f r o m the slick. T h e r e were no significant differences between any of these three other groups. T h e s e findings strongly suggest that the Fulmars deliberately avoided to settle on sea surface that was polluted with heavy oil.
Oil contamination and behavioural modifications of Fulmars Prior to the release of oil, n o n e of the 133 Fulmars o b s e r v e d were visibly c o n t a m i n a t e d by oil. Thus, backg r o u n d c o n t a m i n a t i o n was regarded as insignificant. D u r i n g the first 2 days after the spill the oil slick expanded, and o n 2 July it covered an area of 8.5 X 0.11.5 km. At least 4 0 % o f this area was only covered with blueshine. O n 1 - 2 July, the majority of the Fulmars o b s e r v e d lying on the sea surface were just outside of the blueshine area (Table 2). T h e general b e h a v i o u r of these birds and of the Fulmars flying a b o u t in the area, indicated that they, given the prevailing conditions, had the ability of avoiding the oil. O n three occasions outside the 10-min observation bouts Fulmars were actually o b s e r v e d on the sea surface within the blueshine area (1, 32, and 8 birds respectively, Table 2). At least eight of these birds (representing 4% of the m a x i m u m n u m b e r of Fulmars o b s e r v e d in the area) had visible tracks of thin oil in their breast feathers, and one of them was additionally c o n t a m i n a t e d by small spots of thick oil. However, n o n e of the oiled birds were seen preening their feathers or in any way advertising that they felt uncomfortable. T h e reason why they were affected m o s t p r o b a b l y was that they were attracted by f o o d remains 'accidentally' thrown o v e r b o a r d f r o m the research vessel into the blueshine area. T h e eight Fulmars o b s e r v e d within the blueshine area the s e c o n d day were, however, o b s e r v e d giving way for a small drifting slick of heavier oil, showing that they were able to detect such oil when lying on the sea surface.
Discussion A l t h o u g h limited, the information o n the vulnerability of Fulmars gained during this experimental oil spill m a y prove valuable to future impact studies and assessments. However, even if m o s t birds seemed capable of avoiding oil in the situations described for
Away from slick Mean 4.66 6.33 X2= 1.98 p > 0.1
Chi-square X2 p
SD 3.57 9.94
0.113 55.0
>0.5 < 0.001
TABLE 2
Observations of Fulmars lying on the sea surface near to or within areas covered by blueshine or heavier oil. Date 1.7
2.7
Hour (GMT)
Number of birds
13.35 13.35 13.35 14.45 14.45 15.30 20.00 20.00 09.00 09.00 10.30 12.50 13.30
40 13 1 115 80 200 80 32 30 40 8 130 70
Position in relation to nearest area with drifting blueshine or heavy oil 150 m behind blueshine area 100 m behind blueshine area Withinblueshine area (close to vessel) 150 m behind blueshine area Closelyin front of blueshine area Besideblueshine area 250 m beside blueshine area Withinblueshine area Besideblueshine area 250 m behind blueshine area Withinblueshine area 150 m in front of heavier oil Dispersedaround the whole slick
this experiment, they may experience greater risks of contamination u n d e r other circumstances, e.g. when fisheries activity is great a n d / o r at times of year when light and weather conditions are prevailingly p o o r (Brown, 1982). Furthermore, the consequences of a m i n o r c o n t a m i n a t i o n of the plumage are probably m u c h greater in winter when temperatures are low and the birds' physiological condition may be reduced ( N E R C , 1971). T h e behaviour of the few oiled Fulmars observed did not indicate that they were severely affected. However, it is unlikely that the effects of such a light oiling will b e c o m e visible within the first few days after the birds are hit, particularly in s u m m e r when environmental conditions normally are good. In addition to the direct effects of the external oiling, the oiled birds may in time suffer from internal injuries. B o t h during the physical contact with the spill and during preening, they could easily have ingested s o m e oil. It has been shown that various c o m p o n e n t s of oil can cause serious physiological malfunctions in birds (see e.g. Clark, 1984 for a review). Thus, it is not possible to c o n c l u d e that this experiment did not h a r m or even kill any seabirds. O u r study was primarily aimed at trying out different field m e t h o d s in order to test if full-scale experimental oil spills of this kind represent valuable opportunities to investigate the actual oil vulnerability of seabirds at sea. With accidental spills, the time necessary to implement similar studies is normally not adequate, and they m a y be severely h a m p e r e d by various activities in relation to the spill action. A l t h o u g h our study p r o b a b l y raised m o r e questions than it answered we believe it is of great i m p o r t a n c e to utilize future spill experiments (as well as accidental spill situations) in order to clarify seabird 145
Marine Pollution Bulletin b e h a v i o u r a n d v u l n e r a b i l i t y t o w a r d s oil p o l l u t i o n in the marine environment. We are indebted to B. H. Larsen who assisted in the field and to the crew at the research vessel Endre Dyroy. The oil spill experiment was carried out by the Oceanographic Company of Norway A/S (OCEANOR) with financial support from US Dept. of Interior, Norsk Hydro A/S, the North Sea Directorate in the Netherlands, the Norwegian Clean Seas Association for Operating Companies (NOFO), the Continental Shelf and Petroleum Technology Institute (IKU), FINA and Olivetti Norge. The seabird part of the study was financed by the Royal Norwegian Ministry of Petroleum and Energy. Fritjof Mehlum and Vldar Bakken gave valuable comments on the manuscript.
Anker-Nilssen, T. & Vader, W. (in manuscript). An oil vulnerability index for seabirds. Brown, R. G. B. (1982). Birds, oil and the Canadian environment. In
Oil and dispersants in Canadian seas--Research appraisal and recommendations (J. B. Sprague, J. H. Vandermeulen & P. G. Wells, eds), pp. 105-112. Environment Canada, Environmental Prolection Service Report. Clark, R. B. (1984). Impact of Oil Pollution on Seabirds. Environ. Pollut. (Ser.A) 33, 1-22. Ford, R. G., Wiens, J. A., Heinemann, D. & Hunt, G. L. (1982). Modelling the sensitivity of colonially breeding marine birds to oil spills: Guillemot and Kittiwake populations on the Pribilof islands, Bering sea. J. Appl. Ecol. 19, 1-31. King, J. G. & Sanger, G. A. (1979). Oil vulnerability index for marine oriented birds. In Conservation of marine birds of northern North America (J. C. Bartonek & D. N. Nettleship, eds), pp. 227 239. Fish. Wildl. Serv. Wildl. Res. Rep. No. II. NERC (1971). The sea bird wreck in the Irish Sea, autumn 1969. NERC Publ. Ser. C, No. 4. Natural Environment Research Council, London. Wiens, J. A., Ford, R. G. & Heinemann, D. (1984). Information needs and priorities for assessing the sensitivity of marine birds to oil spills. Biological Conservation 28, 21 49.
0025-326X/93 S6.I}0+0.00 © 1993 Pergamon Press Ltd
Marine Pollution Bulletin, Volume 26, No. 3, pp. 146-151, 1993. Printed in Great Britain.
PCB and DDTs in Blubber of Cetaceans from the Northeastern North Atlantic ASSUMPCIO BORRELL D e p a r t m e n t o f A n i m a l Biology (Vertebrates), Faculty o f Biology, University o f Barcelona, Barcelona 08071, Spain
Blubber from long-finned pilot whales, Atlantic whitesided dolphins and harbour porpoises caught off the Faroe Islands, and from fin whales, sei whales, and sperm whales from Iceland were analysed for organochlorine pollutants. Pollutant levels were positively correlated with increasing trophic level and inversely with body size. For any given species, the %DDE/ Ep,p'-DDT ratio increased with ~p,p'-DDT burden, probably reflecting increased detoxification activity of liver enzymes at higher contaminant concentrations. The %~p,p'-DDT/PCBratio decreased with increasing trophic level suggesting differential transfer rates of the two organochlorine groups through food webs. Because of the effect of transfer of organochlorines through gestation and lactation, ]~p,p'-DDT and PCB levels, %DDE/~Ep,p'-DDT and %Y,p,p'-DDT/PCBratios were higher in males than in females.
O r g a n o c h l o r i n e c o m p o u n d s such as t h o s e p e r t a i n i n g to the family o f D D T s , u s e d as p e s t i c i d e s in agriculture, a n d p o l y c h l o r i n a t e d b i p h e n y l s o r P C B , w h i c h are i m p o r t a n t i n d u s t r i a l c h e m i c a l s u s e d as n o n - f l a m m a b l e oils in m a n y c o m m e r c i a l p r o d u c t s , are e x t r e m e l y 146
p e r s i s t e n t a n d difficult to d e g r a d e . D e s p i t e the fact that these c o m p o u n d s have b e e n f o r b i d d e n in m a n y d e v e l o p e d c o u n t r i e s a n d their w o r l d w i d e p r o d u c t i o n a n d use have d r a s t i c a l l y d e c r e a s e d in r e c e n t y e a r s (de V o o g t & B r i n k m a n , 1989), at p r e s e n t they are w i d e l y s p r e a d a n d h a v e b e c o m e u b i q u i t o u s c o n t a m i n a n t s of n a t u r a l systems. N o w a d a y s , P C B s are the m o s t a b u n d a n t c h l o r i n a t e d a r o m a t i c c o n t a m i n a n t s in the ecosystem. B e c a u s e m o s t o r g a n o c h l o r i n e c o n t a m i n a n t s are e x t r e m e l y l i p o p h i l i c a n d resistant to d e g r a d a t i o n , they t e n d to c o n c e n t r a t e a n d b i o m a g n i f i c a t e t h r o u g h f o o d webs. M o r e o v e r , it has b e e n s h o w n that the ability o f small c e t a c e a n s to m e t a b o l i z e P C B s is e x t r e m e l y low as c o m p a r e d to that of b i r d s a n d terrestrial m a m m a l s ( T a n a b e et al., 1988). T h e s e two facts e x p l a i n why s o m e m a r i n e m a m m a l s situated at the highest t r o p h i c level c a r r y v e r y high c o n t a m i n a n t loads. In m a m m a l s , P C B s are k n o w n to i n d u c e p a t h o l o g i c a l changes in the r e p r o d u c t i v e o r g a n s a n d cycle. This effect, t o g e t h e r with the ability o f these c o m p o u n d s to interfere with the d y n a m i c s o f r e p r o d u c t i v e h o r m o n e s , has b e e n c l a i m e d to d e p r e s s the r e p r o d u c t i v e p o t e n t i a l o f several m a m m a l s ( F u l l e r & H o b s o n , 1986; R e i j n d e r s , 1986). F o r e x a m p l e , t h e r e is e v i d e n c e that
Marine Pollution Bulletin, Volume 26, No. 3, pp. 144 146, 1993. Printed in Great Britain.
Behaviour and Oil Vulnerability of Fulmars Fulmarus glacialis During an Oil Spill Experiment in the Norwegian Sea SVEIN-HAKON L O R E N T S E N and TYCHO ANKER-NILSSEN Norwegian Institute for Nature Research, Tungasletta 2, N-7005 Trondheim, Norway
The behaviour and oil vulnerability of Fulmars was studied when 30 t of crude oil was experimentally released at Haltenbanken, 150 km off the coast of Central Norway in July 1989. Evidence strongly suggests that the Fulmars deliberately avoided to settle on sea surface that was polluted with heavy oil. However, about 4% of the Fulmars in the area were slightly oiled, probably because they had been attracted to surrounding blueshine areas by food remains thrown overboard from the research vessel.
Impact assessments of oil pollution on seabirds worldwide have shown that it is necessary, beside having basic knowledge about population dynamics, to gain more exact knowledge on the behaviour of seabirds in relation to oil spills at sea as well as their risk of getting contaminated (Wiens et al., 1984). Such knowledge is essential to improve the validity of the different impact assessment models used (e.g. King & Sanger, 1979; Ford et al., 1982; Anker-Nilssen & Vader, in manuscript). It is particularly important to obtain reliable estimates of the proportions of birds in a spill area that will become oiled, and which factors that influence this parameter (e.g. species, age, sex, season, light, weather). Up to now, information about seabird behaviour in relation to oil spills has only been found in obscure publications and reports. Behavioural studies under otherwise natural conditions are, as far as we know, still scarce. During a full-scale experimental oil spill at Haltenbanken off Central Norway in July 1989 we conducted studies aimed at gathering information about Fulmar (Fulmarus glacialis) behaviour and vulnerability in relation to oil at sea. The Fulmar is normally the only seabird that occurs in any numbers in this area during summer (Norwegian Seabird Register, unpubl, data), probably mainly because the area is too distant for most seabirds breeding along the Norwegian coast. Materials and Methods
The oil spill experiment was carried out primarily to 144
study different methods of oil spill detection and tracking, but was also designed to investigate oil weathering and conflicts between oil and seabirds at sea. On 1 July 1989, 30 t of Oseberg crude oil was released at Haltenbanken (spill site 65°00'N, 08°00'E) about 150 km off the coast of Central Norway. The oil slick was followed for 5 days at which time most of the oil had either evaporated or dissolved into the water column. The spill site was chosen in advance according to drift model simulations which estimated the probability of oil reaching land within 5 days to be less than 1%. Permission to conduct the experiment was given by the Norwegian State Pollution Control Authority. Shortly after the release of oil and during the following day the numbers of Fulmars in different directions from the oil slick was recorded. The weather was good with calm sea and air temperatures above 10°C. The research vessel was located at the edge of the slick and two observers counted simultaneously all birds within an area of 300 x 300 m on each side of the boat during nine 10-min intervals, such that one always observed towards the slick while the other covered the opposite direction. These observations were restricted to periods when there were no other activities that could have influenced the distribution of birds. Birds lying on the sea surface and birds flying were treated separately. On 3-4 July heavy wind and waves followed by fog made similar observations impossible. To obtain data on the background contamination of Fulmars in the Haltenbanken area all birds observed before the experiment started (i.e. on 27 and 28 June) were checked for any oil contamination. Throughout the whole experiment (1-6 July) notes were made of Fulmar behaviour and of all oil contaminated birds observed. Results
Fulmar distribution in relation to the oil slick During the first 2 days of the experiment, the distribution of Fulmars on the sea surface and in air towards and from the oil slick was strikingly uneven (X z= 33.7, d f = l , p < 0.001, Table 1). Not a single bird
Volume 26/Number 3/March 1993 TABLE 1
Numbers of Fulmars (totals and 10-min interval means) flying above or lying on the sea surface in directions to and from the most heavily polluted part of the oil slick during the first 2 days of the oil spill. Observations were done simultaneously in both directions during nine 10-min intervals. The results of Chi-square tests (with Yates correction for continuity) are indicated. Behaviour
N
Flying On surface Chi-square
38 0
Towards slick Mean
SD
N
4.22 2.77 0.00 0.00 X2= 36.0 p < 0.001
42 57
was o b s e r v e d o n the sea surface in the sector facing the oil spill. In significant contrast to this, the m e d i a n n u m b e r of flying birds o b s e r v e d per 10-min interval was three in b o t h directions, as was the m e d i a n n u m b e r of birds lying o n the surface in the sector away f r o m the slick. T h e r e were no significant differences between any of these three other groups. T h e s e findings strongly suggest that the Fulmars deliberately avoided to settle on sea surface that was polluted with heavy oil.
Oil contamination and behavioural modifications of Fulmars Prior to the release of oil, n o n e of the 133 Fulmars o b s e r v e d were visibly c o n t a m i n a t e d by oil. Thus, backg r o u n d c o n t a m i n a t i o n was regarded as insignificant. D u r i n g the first 2 days after the spill the oil slick expanded, and o n 2 July it covered an area of 8.5 X 0.11.5 km. At least 4 0 % o f this area was only covered with blueshine. O n 1 - 2 July, the majority of the Fulmars o b s e r v e d lying on the sea surface were just outside of the blueshine area (Table 2). T h e general b e h a v i o u r of these birds and of the Fulmars flying a b o u t in the area, indicated that they, given the prevailing conditions, had the ability of avoiding the oil. O n three occasions outside the 10-min observation bouts Fulmars were actually o b s e r v e d on the sea surface within the blueshine area (1, 32, and 8 birds respectively, Table 2). At least eight of these birds (representing 4% of the m a x i m u m n u m b e r of Fulmars o b s e r v e d in the area) had visible tracks of thin oil in their breast feathers, and one of them was additionally c o n t a m i n a t e d by small spots of thick oil. However, n o n e of the oiled birds were seen preening their feathers or in any way advertising that they felt uncomfortable. T h e reason why they were affected m o s t p r o b a b l y was that they were attracted by f o o d remains 'accidentally' thrown o v e r b o a r d f r o m the research vessel into the blueshine area. T h e eight Fulmars o b s e r v e d within the blueshine area the s e c o n d day were, however, o b s e r v e d giving way for a small drifting slick of heavier oil, showing that they were able to detect such oil when lying on the sea surface.
Discussion A l t h o u g h limited, the information o n the vulnerability of Fulmars gained during this experimental oil spill m a y prove valuable to future impact studies and assessments. However, even if m o s t birds seemed capable of avoiding oil in the situations described for
Away from slick Mean 4.66 6.33 X2= 1.98 p > 0.1
Chi-square X2 p
SD 3.57 9.94
0.113 55.0
>0.5 < 0.001
TABLE 2
Observations of Fulmars lying on the sea surface near to or within areas covered by blueshine or heavier oil. Date 1.7
2.7
Hour (GMT)
Number of birds
13.35 13.35 13.35 14.45 14.45 15.30 20.00 20.00 09.00 09.00 10.30 12.50 13.30
40 13 1 115 80 200 80 32 30 40 8 130 70
Position in relation to nearest area with drifting blueshine or heavy oil 150 m behind blueshine area 100 m behind blueshine area Withinblueshine area (close to vessel) 150 m behind blueshine area Closelyin front of blueshine area Besideblueshine area 250 m beside blueshine area Withinblueshine area Besideblueshine area 250 m behind blueshine area Withinblueshine area 150 m in front of heavier oil Dispersedaround the whole slick
this experiment, they may experience greater risks of contamination u n d e r other circumstances, e.g. when fisheries activity is great a n d / o r at times of year when light and weather conditions are prevailingly p o o r (Brown, 1982). Furthermore, the consequences of a m i n o r c o n t a m i n a t i o n of the plumage are probably m u c h greater in winter when temperatures are low and the birds' physiological condition may be reduced ( N E R C , 1971). T h e behaviour of the few oiled Fulmars observed did not indicate that they were severely affected. However, it is unlikely that the effects of such a light oiling will b e c o m e visible within the first few days after the birds are hit, particularly in s u m m e r when environmental conditions normally are good. In addition to the direct effects of the external oiling, the oiled birds may in time suffer from internal injuries. B o t h during the physical contact with the spill and during preening, they could easily have ingested s o m e oil. It has been shown that various c o m p o n e n t s of oil can cause serious physiological malfunctions in birds (see e.g. Clark, 1984 for a review). Thus, it is not possible to c o n c l u d e that this experiment did not h a r m or even kill any seabirds. O u r study was primarily aimed at trying out different field m e t h o d s in order to test if full-scale experimental oil spills of this kind represent valuable opportunities to investigate the actual oil vulnerability of seabirds at sea. With accidental spills, the time necessary to implement similar studies is normally not adequate, and they m a y be severely h a m p e r e d by various activities in relation to the spill action. A l t h o u g h our study p r o b a b l y raised m o r e questions than it answered we believe it is of great i m p o r t a n c e to utilize future spill experiments (as well as accidental spill situations) in order to clarify seabird 145
Marine Pollution Bulletin b e h a v i o u r a n d v u l n e r a b i l i t y t o w a r d s oil p o l l u t i o n in the marine environment. We are indebted to B. H. Larsen who assisted in the field and to the crew at the research vessel Endre Dyroy. The oil spill experiment was carried out by the Oceanographic Company of Norway A/S (OCEANOR) with financial support from US Dept. of Interior, Norsk Hydro A/S, the North Sea Directorate in the Netherlands, the Norwegian Clean Seas Association for Operating Companies (NOFO), the Continental Shelf and Petroleum Technology Institute (IKU), FINA and Olivetti Norge. The seabird part of the study was financed by the Royal Norwegian Ministry of Petroleum and Energy. Fritjof Mehlum and Vldar Bakken gave valuable comments on the manuscript.
Anker-Nilssen, T. & Vader, W. (in manuscript). An oil vulnerability index for seabirds. Brown, R. G. B. (1982). Birds, oil and the Canadian environment. In
Oil and dispersants in Canadian seas--Research appraisal and recommendations (J. B. Sprague, J. H. Vandermeulen & P. G. Wells, eds), pp. 105-112. Environment Canada, Environmental Prolection Service Report. Clark, R. B. (1984). Impact of Oil Pollution on Seabirds. Environ. Pollut. (Ser.A) 33, 1-22. Ford, R. G., Wiens, J. A., Heinemann, D. & Hunt, G. L. (1982). Modelling the sensitivity of colonially breeding marine birds to oil spills: Guillemot and Kittiwake populations on the Pribilof islands, Bering sea. J. Appl. Ecol. 19, 1-31. King, J. G. & Sanger, G. A. (1979). Oil vulnerability index for marine oriented birds. In Conservation of marine birds of northern North America (J. C. Bartonek & D. N. Nettleship, eds), pp. 227 239. Fish. Wildl. Serv. Wildl. Res. Rep. No. II. NERC (1971). The sea bird wreck in the Irish Sea, autumn 1969. NERC Publ. Ser. C, No. 4. Natural Environment Research Council, London. Wiens, J. A., Ford, R. G. & Heinemann, D. (1984). Information needs and priorities for assessing the sensitivity of marine birds to oil spills. Biological Conservation 28, 21 49.
0025-326X/93 S6.I}0+0.00 © 1993 Pergamon Press Ltd
Marine Pollution Bulletin, Volume 26, No. 3, pp. 146-151, 1993. Printed in Great Britain.
PCB and DDTs in Blubber of Cetaceans from the Northeastern North Atlantic ASSUMPCIO BORRELL D e p a r t m e n t o f A n i m a l Biology (Vertebrates), Faculty o f Biology, University o f Barcelona, Barcelona 08071, Spain
Blubber from long-finned pilot whales, Atlantic whitesided dolphins and harbour porpoises caught off the Faroe Islands, and from fin whales, sei whales, and sperm whales from Iceland were analysed for organochlorine pollutants. Pollutant levels were positively correlated with increasing trophic level and inversely with body size. For any given species, the %DDE/ Ep,p'-DDT ratio increased with ~p,p'-DDT burden, probably reflecting increased detoxification activity of liver enzymes at higher contaminant concentrations. The %~p,p'-DDT/PCBratio decreased with increasing trophic level suggesting differential transfer rates of the two organochlorine groups through food webs. Because of the effect of transfer of organochlorines through gestation and lactation, ]~p,p'-DDT and PCB levels, %DDE/~Ep,p'-DDT and %Y,p,p'-DDT/PCBratios were higher in males than in females.
O r g a n o c h l o r i n e c o m p o u n d s such as t h o s e p e r t a i n i n g to the family o f D D T s , u s e d as p e s t i c i d e s in agriculture, a n d p o l y c h l o r i n a t e d b i p h e n y l s o r P C B , w h i c h are i m p o r t a n t i n d u s t r i a l c h e m i c a l s u s e d as n o n - f l a m m a b l e oils in m a n y c o m m e r c i a l p r o d u c t s , are e x t r e m e l y 146
p e r s i s t e n t a n d difficult to d e g r a d e . D e s p i t e the fact that these c o m p o u n d s have b e e n f o r b i d d e n in m a n y d e v e l o p e d c o u n t r i e s a n d their w o r l d w i d e p r o d u c t i o n a n d use have d r a s t i c a l l y d e c r e a s e d in r e c e n t y e a r s (de V o o g t & B r i n k m a n , 1989), at p r e s e n t they are w i d e l y s p r e a d a n d h a v e b e c o m e u b i q u i t o u s c o n t a m i n a n t s of n a t u r a l systems. N o w a d a y s , P C B s are the m o s t a b u n d a n t c h l o r i n a t e d a r o m a t i c c o n t a m i n a n t s in the ecosystem. B e c a u s e m o s t o r g a n o c h l o r i n e c o n t a m i n a n t s are e x t r e m e l y l i p o p h i l i c a n d resistant to d e g r a d a t i o n , they t e n d to c o n c e n t r a t e a n d b i o m a g n i f i c a t e t h r o u g h f o o d webs. M o r e o v e r , it has b e e n s h o w n that the ability o f small c e t a c e a n s to m e t a b o l i z e P C B s is e x t r e m e l y low as c o m p a r e d to that of b i r d s a n d terrestrial m a m m a l s ( T a n a b e et al., 1988). T h e s e two facts e x p l a i n why s o m e m a r i n e m a m m a l s situated at the highest t r o p h i c level c a r r y v e r y high c o n t a m i n a n t loads. In m a m m a l s , P C B s are k n o w n to i n d u c e p a t h o l o g i c a l changes in the r e p r o d u c t i v e o r g a n s a n d cycle. This effect, t o g e t h e r with the ability o f these c o m p o u n d s to interfere with the d y n a m i c s o f r e p r o d u c t i v e h o r m o n e s , has b e e n c l a i m e d to d e p r e s s the r e p r o d u c t i v e p o t e n t i a l o f several m a m m a l s ( F u l l e r & H o b s o n , 1986; R e i j n d e r s , 1986). F o r e x a m p l e , t h e r e is e v i d e n c e that