Monitoring and assessment of the proportion of oiled Common Guillemots from beached bird surveys in The Netherlands: update winter 2014/15

Abstract

This is the annual update for OSPAR of the beached bird survey (BBS) results in The Netherlands (winter 2014/15). The Dutch BBS provides data for OSPAR area’s 8, 9 and 10, but data from Belgian and German colleagues will have to be merged to arrive at the final values for these areas. For the Dutch North Sea region, significant declines in oil rates were reported over a long study period (1977/78-2013/14) as well as (clearly accelerating) over the last 10-15 years. In winter 2014/15, densities of pelagic seabirds washing ashore were again very low. Some oil incidents (mystery spills, no source known, deduced from stranded seabirds) were recorded in Zeeland, affecting mostly Common Guillemots, but numbers stranded remained low.
The (Dutch) national oil rate of Common Guillemots in winter 2014/15 amounted to 32.4% (n= 37), with the five-year running mean over 20010/11-2014/15 (mean ± SD) at 30.2 ± 11.6%. For five other selected offshore species, not a single oiled carcass was reported, but the sample size was too small for a meaningful assessment of the annual oil rate. The results obtained over the last decade suggest an continuation of low oil rates in Common Guillemots in Dutch waters. Following the significant trends in the most recent data set (1999/00-present), a projection for 2020 would arrive at c. 19% (logit -0.64).

Full text

Monitoring and assessment of the
Monitoring and assessment of the
proportion of oiled Common
proportion of oiled Common
Guillemots from beached bird surveys
Guillemots from beached bird surveys
in The Netherlands: update winter
in The Netherlands: update winter
2014/15
2014/15
C.J. Camphuysen
Texel, december 2015
NIOZ Koninklijk Nederlands Instituut voor Onderzoek der Zee

Front cover:
Selection of photos of stranded Common Guillemots from www.waarneming.nl for the period 1 Nov 2014-30 April 2015. None of the guillemots
depicted are oiled.
Large photo stranded Common Guillemot courtesy Jan Andries van Franeker
Commissioners contact details:
Ministry of Infrastructure and the Environment (I&M), Postbus 5023 | 2600 GA | Delft, The
Netherlands.
Contact: Mervyn Roos, RWS-CIV mervyn.roos@rws.nl
RWS Centrale Informatievoorziening BM 15.19
Author's contact details:
Royal Netherlands Institute for Sea Research and the Dutch Seabird Group, P.O. Box 59 | 1790
AB | Den Burg, Texel, The Netherlands.
Contact: Dr Kees (C.J.) Camphuysen, senior researcher, E-mail kees.camphuysen@nioz.nl
+31 222 369488
Citation:
Camphuysen C.J. (2015). Monitoring and assessment of the proportion of oiled Common
Guillemots from beached bird surveys in The Netherlands: update winter 2014/15. NIOZ
Report 2015-04, RWS Centrale Informatievoorziening BM 15.19, Nov 2015. Royal
Netherlands Institute for Sea Research, Texel.

Commissioners contact details:
Ministry of Infrastructure and the Environment (I&M), Dir. Inwinning en
gegevensanalyse, Afd. Datamanagement Center; Centrale Informatievoor-
ziening Rijkswaterstaat; Postbus 5023 | 2600 GA | Delft, The Netherlands.
Contact: Mervyn Roos, RWS-CIV mervyn.roos@rws.nl
RWS Centrale Informatievoorziening BM 15.19
Author’s contact details:
Royal Netherlands Institute for Sea Research and the Dutch Seabird
Group, P.O. Box 59 | 1790 AB | Den Burg, Texel, The Netherlands.
Contact: Dr Kees (C.J.) Camphuysen, senior researcher, E-mail kees.
camphuysen@nioz.nl
+31 222 369488
Citation:
Camphuysen C.J. (2015). Monitoring and assessment of the proportion of
oiled Common Guillemots from beached bird surveys in The Netherlands:
update winter 2014/15. NIOZ Report 2015-04, RWS Centrale Informa-
tievoorziening BM 15.19, Nov 2015. Royal Netherlands Institute for Sea
Research, Texel.

2
Monitoring and assessment of the proportion of oiled Common
Guillemots from beached bird surveys in The Netherlands: annual
update winter 2014/15
Summary
This is the annual update for OSPAR of the beached bird survey (BBS) results in The Netherlands (winter
2014/15). The Dutch BBS provides data for OSPAR area’s 8, 9 and 10, but data from Belgian and German
colleagues will have to be merged to arrive at the final values for these areas. For the Dutch North Sea
region, significant declines in oil rates were reported over a long study period (1977/78-2013/14) as well
as (clearly accelerating) over the last 10-15 years. In winter 2014/15, densities of pelagic seabirds washing
ashore were again very low. Some oil incidents (mystery spills, no source known, deduced from stranded
seabirds) were recorded in Zeeland, affecting mostly Common Guillemots, but numbers stranded remained
low.
The (Dutch) national oil rate of Common Guillemots in winter 2014/15 amounted to 32.4% (n=
37), with the five-year running mean over 20010/11-2014/15 (mean ± SD) at 30.2 ± 11.6%. For five other
selected offshore species, not a single oiled carcass was reported, but the sample size was too small for a
meaningful assessment of the annual oil rate. The results obtained over the last decade suggest an
continuation of low oil rates in Common Guillemots in Dutch waters. Following the significant trends in
the most recent data set (1999/00-present), a projection for 2020 would arrive at c. 19% (logit -0.64).

3
Monitoring en vaststelling van het percentage met olie besmeurde
Zeekoeten door middel van systematische strandtellingen in
Nederland; jaarlijkse rapportage, winter 2014/15
Samenvatting
Dit is de jaarlijkse weergave voor OSPAR van de resultaten van systematische strandtellingen langs de
Nederlandse kust, met een verslag over het seizoen 2014/15. Middels deze tellingen verzorgt Nederland
haar bijdragen voor de OSPAR deelgebieden 8, 9, en 10. Om een compleet beeld te krijgen voor deze
deelgebieden zullen Belgische en Duitse gegevens moeten worden toegevoegd en gecombineerd. In deze
rapportage worden alleen de Nederlandse gegevens besproken. Voor de Nederlandse Noordzeekust kon de
lange termijn afname in oliebevuilingspercentages (1977/78-2013/14) bij de Zeekoeten worden bevestigd.
Over de laatste jaren versnelt deze afname.
In de winter van 2014/15 spoelden opnieuw erg weinig vogels aan. Het (Nederlandse) nationale
oliebevuilingspercentage van de Zeekoet in de winter van 2014/15, gemeten langs het strand, bedroeg
32.4% (n= 37), hetgeen vrijwel gelijk is aan het vijfjaarlijks lopend gemiddelde over 20010/11-2014/15
(gemiddeld ± SD 30.2 ± 11.6%). Het aantal aangespoelde Zeekoeten was lager dan ooit en ook hier is
sprake van een lange-termijn trend. Bij geen van de andere soorten, inclusief de andere geselecteerde
zeevogelsoorten werden, deze winter met olie besmeurde individuen aangetroffen. Voor de meeste soorten
was de steekproef (door het geringe aantal strandingen) te klein om een betekenisvol percentage te
berekenen, maar de indruk van een geringe mate van chronische olievervuiling werd hiermee krachtig
bevestigd.
De oliebevuilingspercentages lijken de afgelopen Jaren (vooral de afgelopen 10 jaren) steeds
sneller af te nemen. Op basis van de lineaire regressie berekend over de logit-oliebevuilingspercentages in
deze eeuw (1999/00-2014/15) waarover een significante dalende trend werd gevonden, zou het
bevuilingspercentage in 2020 uitkomen op ±19% (logit -0.64).

4
Introduction
The effectiveness of measures against (chronic) oil pollution, and of any temporal and spatial
trends existing and developing in past and current levels of chronic oil pollution can be effectively
monitored through beached bird surveys: counts of stranded seabirds on North Sea coasts, coupled
with the assessment of oil rates (proportion of birds oiled; Furness & Camphuysen 1997,
Camphuysen & Heubeck 2001). Species-specific oil rates reflect the risk for various species of
marine birds to become oiled at sea, with high oil rates being more characteristic for seabirds that
are particularly common in areas with frequent oil spills and that have a behaviour that puts them
at risk (a swimming and diving life-style); lower oil rates were found in more aerial seabirds,
especially those wintering away from the busiest shipping lanes (Furness & Camphuysen 1997,
Camphuysen 2010). Common Guillemots, abundant and widespread wing-propelled pursuit
seabirds in NW European waters, are particularly useful in this context. By monitoring the
occurrence of oil on carcasses of guillemots washing ashore around Europe, spatial and temporal
trends in chronic oil pollution can be derived over large geographical scales and over long time-
series.
The information need for the monitoring and assessment of oil fouling of seabirds, in
particular the Common Guilemot, was first established in the OSPAR organization in the form of
an OSPAR Ecological Quality Objective (EcoQO). The Marine Strategy Framework Directive
demands in the Commission Decision of 2010, Chapter 8.2, Effects of contaminants, an indicator
for oil pollution (EU 2010). In the legal Dutch Kader Richtlijn Marien document, page 78
Vervuilende stoffen (Anon, 2012)., the Oiled Guillemot EcoQO indicator is explicitly
implemented. In the EcoQOs for the North Sea, “the Proportion of oiled Common Guillemots
among those found dead or dying on beaches” was subsequently listed Under Issue 4 (Seabirds),
EcoQO element (f). The “Oiled Guillemot EcoQO”, as agreed by the 5th North Sea Conference,
was defined as: “The proportion of such birds should be 10% or less of the total found dead or
dying, in all areas of the North Sea” (Anon. 2002), later refined to target mean proportions of 20%
in 2020 and 10% in 2030 over periods of at least 5 years (Anon. 2012). The present document is
the annual update for The Netherlands for winter 2014/15. All data collected since winter 1997/78
are incorporated in this report. Oil-rates (% oiled) of Common Guillemots are provided for the
Dutch North Sea coast as a whole (monitoring an area of 299 km in length), and for the Dutch
contributions to OSPAR areas 8 (238 km), 9 (61 km), and 10 (299 km; see Methods). Raw data
are provided in Appendices and an analysis of recent trends is provided in the Results section of
this report. While the emphasis of this study is on Common Guillemots, similar data are collected
for all stranded birds and details are provided on five other species in this report: two further
offshore seabirds (the Black-legged Kittiwake Rissa tridactyla and the Razorbill Alca torda) and
three inshore or more coastal species (Herring Gull Larus argentatus, Common Eider Somateria
mollissima, and Common Scoter Melanitta nigra). All six species are illustrated below:

5
Selected offshore seabirds
Common Guillemot
Uria aalge
Razorbill
Alca torda
Black-legged Kittiwake
Rissa tridactyla
Selected nearshore or coastal seabirds
Common Eider
Somateria mollissima
Common Scoter
Melanitta nigra
Herring Gull
Larus argentatus
Methods
With the “Oiled Guillemot EcoQO”, the significance of chronic oil pollution in particular sea areas
is assessed by means of beached bird surveys, in which stranded dead or dying seabirds (notably
Common Guillemots) are checked for the presence or absence of mineral oil in their feathers
(Camphuysen & Heubeck 2001). Surveys are conducted in winter (Nov-Apr), when the effects of
chronic oil pollution are most pronounced and when (illegal) discharges at sea under cover of
darkness (i.e. at night) are frequent (Vollaard 2013). Stranded seabirds are identified, aged if
possible, and the carcass is examined for the presence of oil in the feathers. Other evident causes
of death are recorded simultaneously and in case of mass strandings, a special investigation is
organised in order to try and explain the event. The “Oiled Guillemot EcoQO” uses ratios (the
proportion of birds oiled from the total number of birds found) rather than absolute numbers of
birds washing ashore.
In order to evaluate trends in oil rates, as described in earlier proposals (Camphuysen 2002,
2004, OSPAR 2004, Camphuysen 2005ab, OSPAR 2005), all incomplete carcasses were excluded
from the analysis of beached bird survey results (the presence or absence of oil in the feathers
cannot reliably be studied in incomplete remains of birds). The remainder (nTotal) was split in
fractions of unoiled (nUnoiled) and oiled (nOiled) individuals. Only substances that were visually

6
classified as mineral oil were considered here. An acceptable oil rate (nOiled/nTotal*100) for
Common Guillemots is based on at least 25 complete carcasses of stranded seabirds per annum
per area (i.e. quality code 01, see Appendices) and is otherwise considered ‘unreliable’ (quality
code 00). Annual winter values (% oiled) are provided in bar graphs, with a running (arithmetic)
mean calculated over five-year periods (i.e. the mean of five annual values preceding and including
a particular value), superimposed with a line graph to illustrate the most recent trends. Lower
quality assessments (00, percentages based on less than 25 complete carcasses) are indicated with
a lighter shading. To facilitate a trend analysis by means of linear regression, the oil-rates were
logit-transformed in order to obtain normalised data distributions, following recommendations in
Camphuysen & Van der Meer 1996 (=LOG((x/100)/(1-(x/100))); see also Camphuysen 1995,
1997). For this part of the analysis, lower quality data (quality code 00) were excluded.
The Dutch beached bird surveys contribute to three OSPAR areas, but additional data are
required from neighboring countries in each case:
OSPAR 8  Eastern Southern Bight mainland coast Belgian/French border to Texel (B, NL)
OSPAR 9 Southern German Bight North Sea coast Frisian Islands Texel to Elbe (NL, FRG)
OSPAR 10  Western Wadden Sea mainland and Wadden Sea coast Frisian Islands Texel to Elbe (NL, FRG)
The NZG/NSO beached bird survey monitoring of these areas consists of 93 discrete sections of
coast over 598 km (OSPAR area 8, 38 sections, 238km; area 9, 11 sections, 61km; and area 10, 44
sections, 299 km). Half that area consists of coastline bordering the North Sea, the other half
borders the western Wadden Sea (i.e. more sheltered waters with particularly intense controls of
the occurrence of marine pollution). A “national value” of oil rates is provided by lumping all
censuses conducted along the North Sea coast (i.e. a combination of the Dutch contributions to
OSPAR areas 8 and 9).
Observer effort
Since winter 1977/1978, beached bird surveys have been organised by the Dutch Seabird group.
Effort peaked in the 1980s, as a result of the enormous numbers of oiled seabirds washing ashore
and an army of environmentally concerned volunteers searching beaches. Over the last 10 years,
(arithmetic) mean (± SD) observer effort amounted to 897 ± 309 km per winter. In recent years,
effort is compromised as a result of extremely low numbers of birds washing ashore (Appendix
1). In this season, no less than 37 counts (26%, n= 145) were received during which not a single
corpse of a bird was found. It is difficult to activate volunteers for beached bird surveys if the
rewards (finds) are low. Therefore, data were added from www.waarneming.nl, to compensate for
the low observer effort, in order to obtain a larger data set for analysis, and to achieve a wider
coverage over the entire Dutch coast. The people reporting their finds in waarneming.nl were all
acknowledged and the presence of oil was judged from published photographic material. For

7
Common Guillemots, however, the obtained data from the systematic surveys over the Dutch
North Sea shoreline as a whole were in fact sufficient to calculate reliable oil rates, but the
waarneming.nl material certainly enhanced both area coverage and the sample size.
I am very grateful to the following observers that have provided information on stranded
seabirds in 2014/15: Arnold Gronert, André de Baerdemaeker, Annelies Vriens, Bram Kroese,
Chris Rosmalen, Kees Camphuysen, Carl Zuhorn, David Janssens, Dick Veenendaal, Dirk Kuiken,
Dennis de Heer, Dennis Maas, Erik Holscher, Evelien Dekker, Floor Arts, Frank London, Gerrit
Gerritsen, Hans Bouma, Hans-Werner Neumann, Harmke de Hoogh, Hugo Wieleman, J. Slurp,
Job ten Horn, J. van der Zwaag, Jan Andries van Franeker, Jacob de Vries, Jacques Groen, Joeri
Lamers, Joost de Jong, Leon Kelder, Mardik Leopold, v/h Natuurorganisatie De Windbreker,
Nelleke Groen, Nick Agterberg, Niels Godijn, Patrick Agterberg, Paul van Eik, Ruud Costers,
Rinus Dillerop, Sander Lillipaly, Sanne van den Berg-Blok, Susanne van Donk, Sven Prins, Teun
de Boer, Theo Kiewiet, Vincent Stork, Willem-Pier Vellinga, Wim van Boekel en
www.waarneming.nl
Results
Birds found dead – Overall densities in winter 2014/15 were the lowest on record over the past 4
decades (Fig. 1). The severe storms that occurred washed away material rather than that new
corpses washed ashore and the extremely mild winter (KNMI files) made even rather weak
waterbirds and seabirds survive.
Fig. 1. Long-term trends in densities of sea- and waterbirds (n per km of beach surveyed on a ln scale; all species
combined on all surveyed North Sea shorelines) washing ashore in The Netherlands ranged from a maximum of 10.7
birds km
-1
(2.4 on the ln-scale) in the severe of winter 1978/79 to a minimum of 0.48 birds km
-1
(-0.7) in winter 2014/15

an all-time low number in deposition rates.
y=‐0.0025x
2
+0.0618x+1.203
R²=0.5253
‐1.0
‐0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Ln‐densitiesofstrandedbirdsinTheNetherlands

8
In all 328 carcasses representing 47 species of birds and four species of marine mammals were
recorded during these most recent censuses (Appendix 2). In the top-10, most of the species
featuring in the present report are represented:
Top 10 most numerous species Scientific name Dutch name Total
2060 Eidereend Somateria mollissima Common Eider 41
6340 Zeekoet Uria aalge Common Guillemot 37
5920 Zilvermeeuw Larus argentatus Herring Gull 35
1730 Bergeend Tadorna tadorna Common Shelduck 23
5820 Kokmeeuw Chroicocephalus ridibundus Black-headed Gull 22
6000 Grote Mantelmeeuw Larus marinus Great Black-backed Gull 15
4500 Scholekster Haematopus ostralegus Eurasian Oystercatcher 13
5900 Stormmeeuw Larus canus Mew Gull 11
2130 Zwarte Zeeëend Melanitta nigra Black Scoter 10
6360 Alk Alca torda Razorbill 9
Fig. 2. Annual oil rates in Common Guillemots (n >25 complete carcasses) in The Netherlands (OSPAR areas 8, 9
and 10) along the North Sea beach and 5yr running arithmetic mean oil rates since 1977/78. See Fig. 3 for the overall
trend in oil rates. Note: to conduct a trend analysis, these values were logit-transformed in Fig. 3.
0
10
20
30
40
50
60
70
80
90
100
CommonGuillemots
Annualoilrate
5yrRunningmean

9
Fig. 3. Logit-transformed annual oil rates in Common Guillemots (n >25 complete carcasses) in The Netherlands
(OSPAR areas 8, 9 and 10) along the North Sea beach and 5-year running (arithmetic) mean oil rates since the late
1977/78. A linear regression was calculated over the annual values (dashed line; P< 0.001).
Fig. 4. Overall densities (n km
-1
) in Common Guillemots in The Netherlands (OSPAR areas 8, 9 and 10) along the
North Sea beach since winter 1977/78. An exponential trend line was calculated over the annual values (dashed line),
suggesting a long-term decline, but with highly variable numbers.
y=‐0.0385x+1.179
R²=0.6332
‐4
‐3
‐2
‐1
0
1
2
3
4
Logittransformedoilrates
CommonGuillemots,logitoil‐rate,theNetherlands
Annualvalues
5‐yearrunningmean
y=1.1537e
‐0.041x
R²=0.2284
0.0
0.5
1.0
1.5
2.0
2.5
Numberperkmsearched
CommonGuillemot,TheNetherlands,densities

10
Oil rates in Common Guillemots - The annual oil rate in Common Guillemots along the North
Sea coast declined steadily, and significantly since the late 1970s (Fig. 2-3). Along the North Sea
coast of The Netherlands as a whole, in line with numerous earlier reports, a significant decline in
oil rates can be demonstrated (Fig. 3). In winter 2014/15 the national oil rate arrived at 32.4% (n=
37). The exceptionally low value over 2012/13 (10.9%; n= 55) can be seen as an outlier. The five-
year running (arithmetic) mean has arrived at 31.7 ± 12.7% (Appendix 2). Declining oil rates were
found in all three OSPAR regions covered by Dutch surveys (Appendix 2), but the sample size
within each of these regions (that are in fact all contributions to international datasets to be
analysed with combination with Belgian and German data) is too small to warrant a separate trend
analysis. The densities of Common Guillemots found along the Dutch North Sea shore are plotted
in Fig. 4, and these data show highly variable numbers between seasons (the results of wrecks,
weather and oil spills), but also a long-term decline leading to very low densities in recent years.
The low level of strandings was unforeseen in the 1980s and 1990s when the Oiled Guillemot Eco-
QO was developed, but this is an issue affecting the robustness of recent data (as a result of a
reduced sample size) in The Netherlands, just as it is in neighbouring countries.
Fig. 4. Annual oil rates in Common
Guillemots (n >25 complete carcasses) in
OSPAR area 8 (Eastern Southern Bight
mainland coast Dutch contribution only)
and 5-year running (arithmetic) mean oil
rates since the late 1970s. The quality of the
assessments over 2007/08-2010/11 and
2014/15 (but not 2012/13-13/14!) is low due
to low sample size (few corpses). No oiled
birds in 2013/14, relatively many in
2014/15.
0
10
20
30
40
50
60
70
80
90
100
CommonGuillemotOSPAR8
Annualoilrate
5‐yrrunningmean

11
Fig. 5. Annual oil rates in Common
Guillemots (n >25 complete carcasses) in
OSPAR area 9 (Southern German Bight
Dutch contribution only) and 5-year
running (arithmetic) mean oil rates since
the late 1970s. The quality of the assessment
over 2009/10-2010/11 and 2014/15 is low
due to low sample size (few corpses).
Fig. 6. Annual oil rates in Common
Guillemots (n >25 complete carcasses) in
OSPAR area 10 (Western Wadden Sea
Dutch contribution only) and 5-year
running (arithmetic) mean oil rates since
the late 1970s. The quality of the
assessments over many years (but not
2013/14) is low due to low sample size.
Common Guillemots are and oceanic
species.
.
Fig. 7. Annual oil rates in Razorbills (n >25
complete carcasses) in The Netherlands and
5-year running (arithmetic) mean oil rates
since the late 1970s. See Appendix 7 for the
quality of values. Sample size in 2013/14-
14/15 (none oiled) were too low for an
accurate estimate of oil rates. The five-year
mean is therefore unrealistically low.
Fig. 8. Annual oil rates in Black-legged
Kittiwakes (n >25 complete carcasses) in
The Netherlands and 5-year running
(arithmetic) mean oil rates since the late
1970s. See Appendix 8 for the quality of
values. No reliable data for 2014/15 were
collected (too few intact corpses were
found).
0
10
20
30
40
50
60
70
80
90
100
CommGuillemotOSPAR9
Annualoilrate
5‐yrrunningmean
0
10
20
30
40
50
60
70
80
90
100
CommonGuillemotOSPAR10
Annualoilrate
5‐yrrunningmean
0
10
20
30
40
50
60
70
80
90
100
Razorbill
Annualoilrate
5yrRunningmean
0
10
20
30
40
50
60
70
80
90
100
Kittiwake
Annualoilrate
5yrRunningmean

12
Fig. 9. Annual oil rates in Common Eiders
(n >25 complete carcasses) in The
Netherlands and 5-year running (arithmetic)
mean oil rates since the late 1970s. See
Appendix 9 for the quality of values.
Fig. 10. Annual oil rates in Common Scoters
(n >25 complete carcasses) in The
Netherlands and 5-year running (arithmetic)
mean oil rates since the late 1970s. See
Appendix 10 for the quality of values.
Fig. 11. Annual oil rates in Herring Gulls (n
>25 complete carcasses) in The Netherlands
and 5-year running (arithmetic) mean oil rates
since the late 1970s. See Appendix 11 for the
quality of values.
Oil rates in other offshore seabirds - The other offshore seabirds are characterised by similar
trends (Figs 7-8), but the numbers washing ashore are smaller, also in the recent absence of food-
related or storm-driven mass-mortalities and associated wrecks. The most recent wrecks occurred
in winter 2011/12, resulting in reliable but also spectacularly low oil rates. It is this kind of
mortality events that oil rates are artificially lowered and should be treated with caution.
Oil rates in nearshore seabirds - The long-term trends of the coastal species Common Eiders
(Fig. 9) and Herring Gulls (Fig. 11) are even steeper declines. Oiled carcasses are currently rare,
0
10
20
30
40
50
60
70
80
90
100
CommonEider
Annualoilrate
5yrRunningmean
0
10
20
30
40
50
60
70
80
90
100
CommonScoter
Annualoilrate
5yrRunningmean
0
10
20
30
40
50
60
70
80
90
100
HerringGull
Annualoilrate
5yrRunningmean

13
even along the North Sea coast, indicating a more pronounced decline in oil rates than in offshore
seabirds. Remarkably, the oil rates of the more gregarious Common Scoters (Fig. 10) did not
decline, until rather recently. The decline coincided with a marked decline in overall numbers
washing ashore, and although seawatchers have indicated that Common Scoters today are scarce
in comparison with the 1970s-90s (Camphuysen & Van Dijk 1983, Platteeuw et al. 1994,
www.trektellen.nl), high concentrations of birds have occurred that did not produce higher
numbers of (oiled or unoiled) carcasses.
Recent trends and long-term projection - The long-term trends are evident declines in oil rates
in all species. For Common Guillemots, the r
ecent trend based on logit transformed oil rates over the
most recent winters (1999/00 - 2014/15), for the Dutch North Sea coast as a whole, was significant (P <
0.02; a = 0.56, b= -0.06, r²= 0.46, rms= 0.12, se b= 0.02. t= -3.31, n= 15), leading to a projection of ~ logit
-0.64, or 19% oiled birds for 2020, which is in accordance with the most recent targets
Discussion and conclusion
Beached bird surveys are an essential part of both the Oiled-Guillemot EcoQO as well as for the
plastic particle monitoring conducted by using Northern Fulmar carcasses around the North Sea
(Van Franeker & SNS Fulmar Study Group 2013 and numerous other reports). In winter 2014/15,
very few seabirds washed ashore, frustrating both projects, but the oil rates were again low
signalling a major improvement in marine ecosystems for as far as chronic oil pollution is
concerned (Fig. 1). The 5-year running (arithmetic) mean oil rate in Common Guillemots arrived
at 22.6 ± 11.2% (Fig. 2). The latest results (last decade) suggest an acceleration of the decline in
oil rates. Following the most recent data, (1999/00-present), a projection for 2020 would arrive at
a national oil rate for Common Guillemots of c. 19% (logit -0.64). Apart from some oiled Common
Guillemots, no other oiled carcasses were reported in 2014/15.
Seabird densities in winter 2011/12 were so high that volunteers were easy to stimulate and
readily set out (in numbers!) to search for dead birds. In 2012/13, 2013/14 and again in 2014/15,
numbers of seabirds were so low, that many of them refrained from searching systematically. More
opportunistic reports from www.waarneming.nl, after screening for double counts and
identification errors, were successfully used to enhance the sample size of stranded Common
Guillemots. Fox predation, beach-clean-up operations by NGOs and the more and more frequent
'sand suppletions' are issues that hinder regular beached bird surveys in various ways. Foxes
scavenge and remove corpses, so that intact material (fit for inspection for oil) rapidly turn into
scavenged remains (no longer fit for the assessment of oiling). This problem is well known in

14
many countries, but relatively new for The Netherlands. The data are affected in a sense that fewer
corpses are available for inspection, but the oil-rate (i.e. the value of interest) is not expected to be
influenced by the removal and more rapid decay of carcasses. Sand suppletions make substantial
sectors of coastline (at least temporarily) inaccessible and beach-washed carcasses may be covered
under sand. Both factors hinder assessments of total numbers washing ashore (corpse counts), but
are not expected to negatively affect the oil rate, the value desired by OSPAR for the oiled-seabird
(Guillemot) ECOQo.
The Dutch data collected for OSPAR regions 8 and 9 must be seen as contributions to the
data set. An international co-ordinator, or OSPAR itself, will have to combine Dutch, Belgian and
German data for these areas in order to arrive at OSPAR area specific oil rates for Common
Guillemots in the southeastern North Sea. There is no doubt that similar trends will be revealed as
presented in the current document for the Dutch area as a whole.
References
Anonymous 2002. Bergen Declaration. Ministerial declaration Fifth International Conference on the Protection of the
North Sea, 20-21 March 2002, Bergen, Norway.
Anonymous 2012. Mariene Strategie voor het Nederlandse deel van de Noordzee 2012-2020, Deel 1. Rapport,
Ministeries I&M en ELI, ‘s Gravenhage, The Netherlands.
Anonymous 2014. De Mariene Strategie Deel 2, het Kaderrichtlijn Mariene Strategie-Monitoringprogramma. De
Mariene Strategie voor het Nederlandse deel van de Noordzee 2012-2020 Deel 2, het Kaderrichtlijn Mariene
Strategie-Monitoringprogramma, is op 11 juli, inclusief de bijbehorende Nota van Antwoord, vastgesteld
door de Ministerraad. http://www.noordzeeloket.nl/nieuws/?item=3337
Camphuysen C.J. 1989. Beached Bird Surveys in the Netherlands 1915-1988; Seabird Mortality in the southern North
Sea since the early days of Oil Pollution. Techn. Rapport Vogelbescherming 1, Werkgroep Noordzee,
Amsterdam 322pp.
Camphuysen C.J. 1995. Olieslachtoffers langs de Nederlandse kust als indicatoren van de vervuiling van de zee met
olie. Sula 9(special issue): 1-90, I-XX.
Camphuysen C.J. 1997. Olievervuiling en olieslachtoffers langs de Nederlandse kust: 1969-1997. Ongepubl.
eindrapport aan Directoraat Generaal Scheepvaart & Maritieme Zaken, (Ministerie van Verkeer en
Waterstaat), CSR Consultancy 97-1, Oosterend, Texel, 64pp.
Camphuysen C.J. 2002. Oil rates in Common Guillemots. CSR Report, Project INTERNAT*NZM-DNZ, OSPAR
Biodiveristy Committee, BDC 03/2/4, Annex 1, 22pp.
Camphuysen C.J. 2004. North Sea pilot project on Ecological Quality Objectives, Issue 4. Seabirds, EcoQO element
F. Proportion of oiled Common Guillemots among those found dead or dying - revised edition (June 2004).
CSR Report 2004-012, Texel, 26pp.
Camphuysen C.J. 2005a. Oiled-guillemot-EcoQO - Implementation Document. North Sea Pilot Project on Ecological
Quality Objectives, Issue 4. Seabirds, EcoQO element (f). NIOZ Report, Royal Netherlands Institute for Sea
Research, Texel, 11pp.

15
Camphuysen C.J. 2005b. Background Document on the Ecological Quality Objective on Oiled Guillemots. North Sea
Pilot Project on Ecological Quality Objectives, Biodiversity Series, ISBN 1-904426-91-3. OSPAR
Publication Number: 2005/252.
Camphuysen C.J. 2010. Declines in oil-rates of stranded birds in the North Sea highlight spatial patterns in reductions
of chronic oil pollution. Mar. Poll. Bull. 60: 1299-1306.
Camphuysen C.J. & Dijk J.van 1983. Zee- en kustvogels langs de Nederlandse kust, 1974-79. Limosa 56: 81-230.
Camphuysen C.J. & Heubeck M. 2001. Marine oil pollution and beached bird surveys: the development of a sensitive
monitoring instrument. Environmental Pollution 112: 443-461.
Camphuysen C.J. & Meer J. van der 1996. Recent trends in oiled seabirds. Ad Hoc working group on Monitoring,
Oslo and Paris Convention for the Prevention of Marine Pollution, Environmental Assessment and
Monitoring Committee (ASMO) . MON 1995 summary record: 20-48, Copenhagen.
Dunnet G.M. 1982. Oil pollution and seabird populations. Phil. Trans. R. Soc. London. Ser., B. 297: 413-427.
Dunnet G.M. 1987. Seabirds and North Sea oil. Phil. Trans. R. Soc. London. Ser., B. 316: 513-524.
EU 2010. Commision Decision of 1 september 2010 on criteria and methodological standards on good environmental
status of marine waters, Document nr 2010/477/EU.
Furness R.W. & Camphuysen C.J. 1997. Seabirds as monitors of the marine environment. ICES J. Mar. Sc. 54: 726-
737.
Franeker J.A. van & SNS Fulmar Study Group 2013. Fulmar litter EcoQO monitoring along Dutch and North Sea
coasts - update 2010 and 2011. Report C076/13, Wageningen IMARES, Texel.
IMO 1973/78. International Convention for the Prevention of Pollution from Ships, 1973, modified by the Protocol
of 1978 (MARPOL 73/78). International Maritime Organisation, London, http://www.imo.org/home.asp.
Mörzer Bruijns M.F. & Brouwer G.A. 1959. Report on the numbers of oiled birds found dead on the coast of the
Netherlands, 1948-1958. Rep. Proc. int. Conf. Oil Pollution of the Sea, Copenhagen, 3-4 July 1959, Co-ordin.
Adv. Comm. Oil Poll. Sea: 75-76.
OSPAR Commission 2004. Draft OSPAR Background Document on the Ecological Quality Objective for the
proportion of oiled guillemots amongst those found dead or dying on beaches (Revised version). ECOQO
04/1/3-E, Presented by the Netherlands, Stakeholder Workshop on Ecological Quality Objectives Oslo, 13-
14 December 2004, http://www.dirnat.no/archive/attachments/02/81/0103N028.pdf [online].
OSPAR 2005. Background Document on the Ecological Quality Objective on Oiled Guillemots. North Sea Pilot
Project on Ecological Quality Objectives, Biodiversity Series, ISBN 1-904426-91-3. OSPAR Publication
Number: 2005/252.
Platteeuw M., Ham N.F. van der & Ouden J.E. den 1994. Zeetrektellingen in Nederland in de jaren tachtig. Sula 8: 1-
203.
Vollaard B. 2013. Preventie van illegale olielozingen op de Noordzee: Een onderzoek naar strategisch gedrag van
scheepvaartverkeer. Unpubl. document, Univ. Tilburg.

16
Appendix 1 Observer effort
Kilometers surveyed in beached bird surveys in The Netherlands, winter 1977/78-2014/15. The data for the North Sea
include surveys along the North Sea coast (combining Dutch contributions to OSPAR areas 8-9; see Methods). Total
effort is the sum for all three contributions (OSPAR areas 8-10).
OSPAR8 OSPAR9 OSPAR10 Totals
1977/78 356.0 40.5 7.0 403.5
1978/79 473.2 54.5 3.0 530.7
1979/80 594.7 49.6 3.0 647.3
1980/81 1492.9 154.1 302.0 19 49.0
1981/82 1176.6 145.5 527.5 18 49.6
1982/83 1846.0 205.0 748.8 27 99.8
1983/84 1341.5 264.5 565.6 21 71.6
1984/85 1133.3 133.5 424.0 16 90.8
1985/86 1023.0 95.5 470.0 1588.5
1986/87 708.0 66.5 444.0 12 18.5
1987/88 835.2 112.0 509.4 1456.6
1988/89 951.4 78.0 432.7 1462.1
1989/90 1062.8 122.5 290.5 1475.8
1990/91 1190.8 52.5
123.0 1366.3
1991/92 806.7 76.5 265.5 1148.7
1992/93 678.3 55.0 375.5 1108.8
1993/94 522.5 65.5 482.0 1070.0
1994/95 335.3 57.9 481.3 874.5
1995/96 482.2 86.0 328.0 896.2
1996/97 381.8 54.0 352.5 788.3
1997/98 377.8 95.7 408.0 881.5
1998/99 772.0 264.2 698.5 1734.6
1999/00 646.7 342.1 904.7 1893.5
2000/01 450.3 453.8 690.2 1594.3
2001/02 496.9 489.7 935.5 1922.0
2002/03 805.3 372.3 599.6 1777.2
2003/04
 370.0 308.9 516.1 1195.0
2004/05 284.8 314.8 772.0 1371.6
2005/06 253.4 275.5 582.6 1111.5
2006/07 300.7 268.4 515.1 1084.1
2007/08 231.9 166.0 493.9 891.8
2008/09 238.9 232.0 361.2 832.1
2009/10 225.1 136.5 229.8 591.4
2010/11 276.9 119.8 141.0 537.7
2011/12 301.6 237.4 413.7 952.7
2012/13 218.8 68.7 153.3 440.8
2013/14 254.7 141.4 130.2 526.3
2014/15 237.8 101.0 119.4 458.2

17
Appendix 2 Species found, winter 2014/15
Euring Nederlandsenaam Scientificname Englishname n
0 Geenvogelsgevonden Nobirdsfounddead Nobirdsfounddead 37
20 Roodkeelduiker Gaviastellata Red‐throatedDiver 7
30 Parelduiker Gaviaarctica Black‐throatedDiver 1
90 Fuut Podicepscristatus GreatCrestedGrebe 1
220 NoordseStormvogel Fulmarusglacialis NorthernFulmar 5
550 VaalStormvogeltje Oceanodromaleucorhoa Leach'sStorm‐petrel 1
710 JanvanGent Sulabassana NorthernGannet 5
720 Aalscholver Phalacrocoraxcarbo
 GreatCormorant 5
1220 BlauweReiger Ardeacinerea GreyHeron 1
1610 GrauweGans Anseranser GreylagGoose 3
1670 Brandgans Brantaleucopsis BarnacleGoose 2
1680 Rotgans Brantabernicla BrentGoose 4
1730 Bergeend Tadornatadorna CommonSh elduck 23
1820 Krakeend Anasstrepera Gadwall 2
1840 Wintertaling Anascrecca EurasianTeal 1
1860 Wilde
Eend Anasplatyrhynchos Mallard 6
1890 Pijlstaart Anasacuta NorthernPintail 1
2060 Eidereend Somateriamollissima CommonEider 41
2130 ZwarteZeeëend Melanittanigra BlackScoter 10
4500 Scholekster Haematopusostralegus EurasianOystercatcher 13
4860 Zilverplevier Pluvialissquatarola GreyPlover 1
4930 Kievit Vanellusvanellus NorthernLapwing 1
4960 Kanoetstrandloper Calidriscanutus RedKnot
2
5120 BonteStrandloper Calidrisalpina Dunlin 3
5290 Houtsnip Scolopaxrusticola EurasianWoodcock 2
5340 RosseGrutto Limosalapponica Bar‐tailedGodwit 1
5410 Wulp Numeniusarquata EurasianCurlew 4
5610 Steenloper Arenariainterpres RuddyTurnstone 1
5660 MiddelsteJager Stercorariuspomarinus PomarineSkua 2
5670 KleineJager Stercorariusparasiticus ArcticSkua 1
5690
 GroteJager Stercorariusskua GreatSkua 3
5780 Dwergmeeuw Hydrocoloeusminutus LittleGull 1
5820 Kokmeeuw Chroicocephalusridibundus Black‐headedGull 22
5900 Stormmeeuw Laruscanus MewGull 11
5910 KleineMantelmeeuw Larusfuscus LesserBlack‐backedGull 6
5920 Zilvermeeuw Larusargentatus HerringGull 35
6000 GroteMantelmeeuw Larusmarinus GreatBlack‐
backedGull 15
6020 Drieteenmeeuw Rissatridactyla Black‐leggedKittiwake 3
6340 Zeekoet Uriaaalge CommonGuillemot 37
6345 Alk/Zeekoet Alcatorda/Uriaaalge CommonGuillemot/Razorbill 1
6360 Alk Alcatorda Razorbill 9

18
Euring Nederlandsenaam Scientificname Englishname n
6470 KleineAlk Allealle LittleAuk 2
6540 Papegaaiduiker Fraterculaarctica AtlanticPuffin 2
6655 Postdui
f
 Columba'domestica' domesticpigeon 2
6700 Houtduif Columbapalumbus CommonWoodPigeon 1
11870 Mere l Turdusmerula CommonBlackbird 1
11980 Kramsvogel Turduspilaris Fieldfare 7
12010 Koperwiek Turdusiliacus Redwing 3
15820 Spreeuw Sturnusvulgaris CommonStarling 2
23070 Griend Globicephalamelaena Long‐finnedPilotWhale 1
23510 Bru invis Phocoenaphocoena HarbourPorpoise 7
24320
 GrijzeZeehond Halichoerusgrypus GreySeal 1
24330 GewoneZeehond Phocavitulina CommonSeal 6

19
Appendix 3 Common Guillemot Uria aalge
Oil rates of Common Guillemots in The Netherlands, winter 1977/78-2013/14. The National
survey combines all surveys along the North Sea coast (Dutch contributions to OSPAR 8 and 9).
In all tables: Qual (Quality code) 01 = sufficiently large samples (≥ 25), 00= (too) small samples
NationalCommonGui llemots Annual Annual
Winter nOi led nTotal Oilrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 102 105 1977/78 97.1 01 1977/78 1.53
1978/79 120 139 1978/79 86.3 01 1978/79 0.80
1979/80 168 185 1979/80 90.8 01 1979/80 0.99
1980/81 3426 3759 1980/81 91.1 01 1980/81 1.01
1981/82 890 997 1981/82 89.3 01 90.9 1981/82 0.92 1.00
1982/83 3994 4403 1982/83 90.7 01 89.7 1982/83 0.99 0.94
1983/84 2199 2472 1983/84 89.0 01 90.2 1983/84 0.91 0.96
1984/85 1138 1390 1984/85 81.9 01 88.4 1984/85 0.65 0.88
1985/86 1116 1357 1985/86 82.2 01 86.6 1985/86 0.67 0.81
1986/87 160 175 1986/87 91.4 01 87.0 1986/87 1.03 0.83
1987/88 1477 1562 1987/88 94.6 01 87.8 1987/88 1.24 0.86
1988/89 1231 1672 1988/89 73.6 01 84.7 1988/89 0.45 0.74
1989/90 1221 1540 1989/90 79.3 01 84.2 1989/90 0.58 0.73
1990/91 1733 2073 1990/91 83.6 01 84.5
1990/91 0.71 0.74
1991/92 720 799 1991/92 90.1 01 84.2 1991/92 0.96 0.73
1992/93 462 1107 1992/93 41.7 01 73.7 1992/93 ‐0.14 0.45
1993/94 508 855 1993/94 59.4 01 70.8 1993/94 0.17 0.39
1994/95 336 466 1994/95 72.1 01 69.4 1994/95 0.41 0.36
1995/96 107 179 1995/96 59.8 01 64.6 1995/96 0.17 0.26
1996/97 183 225 1996/97 81.3 01 62.9 1996/97 0.64 0.23
1997/98 334 481 1997/98 69.4 01 68.4 1997/98 0.36 0.34
1998/99 1183 2399 1998/99 49.3 01 66.4 1998/99 ‐0.01 0.30
1999/00 886 1163 1999/00 76.2 01 67.2 1999/00 0.50 0.31
2000/01 221 377 2000/01 58.6 01 67.0 2000/01 0.15 0.31
2001/02 472 811 2001/02 58.2 01 62.4 2001/02 0.14 0.22
2002/03 2151 2402 2002/03 89.6 01 66.4 2002/03 0.93 0.30
2003/04 305 427 2003/04 71.4 01 70.8 2003/04 0.40 0.38
2004/05 351 701 2004/05 50.1 01 65.6 2004/05 0.00 0.28
2005/06 156 288 2005/06 54.2 01 64.7 2005/06 0.07 0.26
2006/07 179 618 2006/07 29.0 01 58.8 
2006/07 ‐0.39 0.16
2007/08 38 82 2007/08 46.3 01 50.2 2007/08 ‐0.06 0.00
2008/09 79 101 2008/09 78.2 01 51.6 2008/09 0.56 0.03
2009/10 35 63 2009/10 55.6 01 52.6 2009/10 0.10 0.05
2010/11 15 34 2010/11 44.1 00 50.6 2010/11 0.01
2011/12 69 238 2011/12 29.0 01 50.6 2011/12 ‐0.39 0.01
2012/13 7 58 2012/13 12.1 01 43.8 2012/13 ‐0.86 ‐0.11
2013/14 25 75 2013/14 33.3 01 34.8 2013/14 ‐0.30 ‐0.27
2014/15 12 37 2014/15 32.4 01 30.2 2014/15 ‐0.32 ‐0.36

20
OSPAR8COMMONGUILLEMOTS
Win ter nOi led nTotal Oi lrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 79 82 1977/78 96.3 01 1977/78 1.42
1978/79 78 93 1978/79 83.9 01 1978/79 0.72
1979/80 111 118 1979/80 94.1 01 1979/80 1.20
1980/81 2782 3078 1980/81 90.4 01 1980/81 0.97
1981/82 589 678 1981/82 86.9 01 90.3 1981/82 0.82 0.97
1982/83 2205 2515 1982/83 87.7 01 88.6 1982/83 0.85 0.89
1983/84 1444 1649 1983/84 87.6 01 89.3 1983/84 0.85 0.92
1984/85 667 863 1984/85 77.3 01 86.0 1984/85 0.53 0.79
1985/86 634 808 1985/86 78.5 01 83.6 1985/86 0.56 0.71
1986/87 96 107 1986/87 89.7 01 84.1 1986/87 0.94 0.72
1987/88 1138 1184 1987/88 96.1 01 85.8 1987/88 1.39 0.78
1988/89 918 1249 1988/89 73.5 01 83.0 1988/89 0.44 0.69
1989/90 1036 1296 1989/90 79.9 01 83.5 1989/90 0.60 0.71
1990/91 1593 1892 
1990/91 84.2 01 84.7 1990/91 0.73 0.74
1991/92 466 524 1991/92 88.9 01 84.5 1991/92 0.90 0.74
1992/93 356 821 1992/93 43.4 01 74.0 1992/93 ‐0.12 0.45
1993/94 343 562 1993/94 61.0 01 71.5 1993/94 0.19 0.40
1994/95 172 248 1994/95 69.4 01 69.4 1994/95 0.35 0.36
1995/96 65 111 1995/96 58.6 01 64.2 1995/96 0.15 0.25
1996/97 124 147 1996/97 84.4 01 63.3 1996/97 0.73 0.24
1997/98 219 306 1997/98 71.6 01 69.0 1997/98 0.40 0.35
1998/99 704 1302 1998/99 54.1 01 67.6 1998/99 0.07 0.32
1999/00 546 691 1999/00 79.0 01 69.5 1999/00 0.58 0.36
2000/01 58 114 2000/01 50.9 01 68.0 2000/01 0.02 0.33
2001/02 220 347 2001/02 63.4 01 63.8 2001/02 0.24 0.25
2002/03 1930 2011 2002/03 96.0 01 68.7 2002/03 1.38 0.34
2003/04 119 142 2003/04 83.8 01 74.6 2003/04 0.71 0.47
2004/05 176 278 2004/05 63.3 01 71.5 2004/05 0.24 0.40
2005/06 47 85 2005/06 55.3 01 72.4 2005/06 0.09 0.42
2006/07 126 382 2006/07 33.0 01 66.3 2006/07
‐0.31 0.29
2007/08 9 18 2007/08 50.0 00 57.1 2007/08
2008/09 19 22 2008/09 86.4 00 57.6 2008/09
2009/10 13 23 2009/10 56.5 00 56.2 2009/10
2010/11 5 9 2010/11 55.6 00 56.3 2010/11
2011/12 32 107 2011/12 29.9 01 55.7 2011/12 ‐0.37 0.10
2012/13 1 28 2012/13 3.6 01 46.4 2012/13 ‐1.43 ‐0.06
2013/14 16 2013/14 0.0 00 29.1 2013/14
2014/15 10 18 2014/15 55.6 00 28.9 2014/15

21
OSPAR9COMMONGUILLEMOTS
Win ter nOi led nTotal Oi lrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 23 23 1977/78 100.0 00 1977/78
1978/79 40 44 1978/79 90.9 01 1978/79 1.00
1979/80 26 27 1979/80 96.3 01 1979/80 1.41
1980/81 212 225 1980/81 94.2 01 1980/81 1.21
1981/82 111 117 1981/82 94.9 01 95.3 1981/82 1.27 1.30
1982/83 332 360 1982/83 92.2 01 93.7 1982/83 1.07 1.17
1983/84 70 96 1983/84 72.9 01 90.1 1983/84 0.43 0.96
1984/85 310 348 1984/85 89.1 01 88.7 1984/85 0.91 0.89
1985/86 114 133 1985/86 85.7 01 87.0 1985/86 0.78 0.82
1986/87 21 21 1986/87 100.0 01 88.0 1986/87 n.d. 0.86
1987/88 151 156 1987/88 96.8 01 88.9 1987/88 1.48 0.90
1988/89 114 117 1988/89 97.4 01 93.8 1988/89 1.58 1.18
1989/90 102 126 1989/90 81.0 01 92.2 1989/90 0.63 1.07
1990/91 122 141 
1990/91 86.5 01 92.3 1990/91 0.81 1.08
1991/92 231 236 1991/92 97.9 01 91.9 1991/92 1.66 1.06
1992/93 29 68 1992/93 42.6 01 81.1 1992/93 ‐0.13 0.63
1993/94 74 114 1993/94 64.9 01 74.6 1993/94 0.27 0.47
1994/95 65 78 1994/95 83.3 01 75.1 1994/95 0.70 0.48
1995/96 26 37 1995/96 70.3 01 71.8 1995/96 0.37 0.41
1996/97 37 49 1996/97 75.5 01 67.3 1996/97 0.49 0.31
1997/98 84 114 1997/98 73.7 01 73.5 1997/98 0.45 0.44
1998/99 299 515 1998/99 58.1 01 72.2 1998/99 0.14 0.41
1999/00 223 277 1999/00 80.5 01 71.6 1999/00 0.62 0.40
2000/01 96 154 2000/01 62.3 01 70.0 2000/01 0.22 0.37
2001/02 165 304 2001/02 54.3 01 65.8 2001/02 0.07 0.28
2002/03 136 213 2002/03 63.8 01 63.8 2002/03 0.25 0.25
2003/04 128 167 2003/04 76.6 01 67.5 2003/04 0.52 0.32
2004/05 87 155 2004/05 56.1 01 62.6 2004/05 0.11 0.22
2005/06 37 84 2005/06 44.0 01 59.0 2005/06 ‐0.10 0.16
2006/07 38 137 2006/07 27.7 01 53.7
2006/07 ‐0.42 0.06
2007/08 20 41 2007/08 48.8 01 50.7 2007/08 ‐0.02 0.01
2008/09 48 57 2008/09 84.2 01 52.2 2008/09 0.73 0.04
2009/10 13 24 2009/10 54.2 00 51.8 2009/10
2010/11 2 9 2010/11 22.2 00 47.4 2010/11
2011/12 32 87 2011/12 36.8 01 49.2 2011/12 ‐0.24 ‐0.01
2012/13 4 25 2012/13 16.0 01 42.7 2012/13 ‐0.72 ‐0.13
2013/14 23 39 2013/14 59.0 01 37.6 2013/14 0.16 ‐0.22
2014/15 1 15 2014/15 6.7 00 28.1 2014/15

22
OSPAR10COMMONGUILLEMOTS
Win ter nOi led nTotal Oi lrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 1977/78
1978/79 1978/79
1979/80 1979/80
1980/81 214 233 1980/81 91.8 01 1980/81 1.05
1981/82 106 115 1981/82 92.2 01 92.0 1981/82 1.07 1.06
1982/83 399 434 1982/83 91.9 01 92.0 1982/83 1.06 1.06
1983/84 127 163 1983/84 77.9 01 88.5 1983/84 0.55 0.88
1984/85 41 47 1984/85 87.2 01 88.2 1984/85 0.83 0.87
1985/86 132 162 1985/86 81.5 01 86.1 1985/86 0.64 0.79
1986/87 15 17 1986/87 100.0 00 87.7 1986/87
1987/88 68 86 1987/88 79.1 01 85.1 1987/88 0.58 0.76
1988/89 66 133 1988/89 49.6 01 79.5 1988/89 ‐0.01 0.59
1989/90 61 83 1989/90 73.5 01 76.7 1989/90 0.44 0.52
1990/91 15 35 1990/91 42.9 01 69.0 1990/91 ‐
0.12 0.35
1991/92 6 6 1991/92 100.0 00 69.0 1991/92
1992/93 63 136 1992/93 46.3 01 62.5 1992/93 ‐0.06 0.22
1993/94 57 107 1993/94 53.3 01 63.2 1993/94 0.06 0.23
1994/95 59 83 1994/95 71.1 01 62.7 1994/95 0.39 0.23
1995/96 4 7 1995/96 57.1 00 65.6 1995/96
1996/97 4 6 1996/97 66.7 00 58.9 1996/97
1997/98 13 21 1997/98 61.9 00 62.0 1997/98
1998/99 107 419 1998/99 25.5 01 56.5 1998/99 ‐0.46 0.11
1999/00 93 152 1999/00 61.2 01 54.5 1999/00 0.20 0.08
2000/01 22 50 2000/01 44.0 01 51.9 2000/01 ‐0.10 0.03
2001/02 71 139 2001/02 51.1 01 48.7 2001/02 0.02 ‐0.02
2002/03 36 77 2002/03 46.8 01 45.7 2002/03 ‐0.06 ‐0.07
2003/04 29 62 2003/04 46.8 01 50.0 2003/04 ‐0.06 0.00
2004/05 44 103 2004/05 42.7 01 46.3 2004/05 ‐0.13
‐0.07
2005/06 34 71 2005/06 47.9 01 47.0 2005/06 ‐0.04 ‐0.05
2006/07 13 79 2006/07 16.5 01 40.1 2006/07 ‐0.71 ‐0.17
2007/08 7 20 2007/08 35.0 00 37.8 2007/08
2008/09 6 9 2008/09 66.7 00 41.7 2008/09
2009/10 7 10 2009/10 70.0 00 47.2 2009/10
2010/11 0 2010/11 00 47.0 2010/11
2011/12 2 30 2011/12 6.7 01 44.6 2011/12 ‐1.15 ‐0.09
2012/13 1 3 2012/13 33.3 00 44.2 2012/13
2013/14 2 16 2013/14 12.5 00 30.6 2013/14
2014/15 0 2014/15 00 2014/15

23
Appendix 7 Razorbill Alca torda
Oil rates of Razorbills in The Netherlands, winter 1977/78-2013/14. The National survey combines
all surveys along the North Sea coast.
Win ter nOi led nTotal Oi lrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 33 35 1977/78 94.3 01 1977/78 1.22
1978/79 36 42 1978/79 85.7 01 1978/79 0.78
1979/80 34 35 1979/80 97.1 01 1979/80 1.53
1980/81 551 573 1980/81 96.2 01 1980/81 1.40
1981/82 114 119 1981/82 95.8 01 93.8 1981/82 1.36 1.18
1982/83 1370 1623 1982/83 84.4 01 91.8 1982/83 0.73 1.05
1983/84 572 615 1983/84 93.0 01 93.3 1983/84 1.12 1.14
1984/85 91 101 1984/85 90.1 01 91.9 1984/85 0.96 1.05
1985/86 137 153 1985/86 89.5 01 90.6 1985/86 0.93 0.98
1986/87 17 19 1986/87 89.5 01 89.3 1986/87 0.93 0.92
1987/88 228 249 1987/88 91.6 01 90.7 1987/88 1.04 0.99
1988/89 168 191 1988/89 88.0 01 89.7 1988/89 0.86 0.94
1989/90 555 784 1989/90 70.8 01 85.9 1989/90 0.38 0.78
1990/91 167 210 1990/91 79.5 01 83.9 1990/91 0.59 0.72
1991/92 68 69 1991/92 98.6 01 85.7
1991/92 1.83 0.78
1992/93 46 67 1992/93 68.7 01 81.1 1992/93 0.34 0.63
1993/94 52 65 1993/94 80.0 01 79.5 1993/94 0.60 0.59
1994/95 75 96 1994/95 78.1 01 81.0 1994/95 0.55 0.63
1995/96 49 162 1995/96 30.2 01 71.1 1995/96 ‐0.36 0.39
1996/97 27 41 1996/97 65.9 01 64.6 1996/97 0.29 0.26
1997/98 68 112 1997/98 60.7 01 63.0 1997/98 0.19 0.23
1998/99 110 157 1998/99 70.1 01 61.0 1998/99 0.37 0.19
1999/00 281 373 1999/00 75.3 01 60.4 1999/00 0.48 0.18
2000/01 20 27 2000/01 74.1 01 69.2 2000/01 0.46 0.35
2001/02 75 135 2001/02 55.6 01 67.1 2001/02 0.10 0.31
2002/03 799 984 2002/03 81.2 01 71.2 2002/03 0.64 0.39
2003/04 67 112 2003/04 59.8 01 69.2 2003/04 0.17 0.35
2004/05 68 225 2004/05 30.2 01 60.2 2004/05 ‐0.36 0.18
2005/06 50 87 2005/06 57.5 01 56.9 2005/06 0.13 0.12
2006/07 58 218 2006/07 26.6 01 51.1 2006/07 ‐0.44 0.02
2007/08 2 17 
2007/08 11.8 01 37.2 2007/08 ‐0.23
2008/09 6 10 2008/09 60.0 01 37.2 2008/09
2009/10 5 14 2009/10 35.7 01 38.3 2009/10
2010/11 5 2010/11 0.0 00 26.8 2010/11
2011/12 12 364 2011/12 3.3 01 22.2 2011/12 ‐1.47
2012/13 1 16 2012/13 6.3 01 21.1 2012/13
2013/14 19 2013/14 0.0 01 9.1 2013/14
2014/15 6 2014/15 0.0 00 1.9 2014/15

24
Appendix 8 Black-legged Kittiwakes Rissa tridactyla
Oil rates of Black-legged Kittiwakes in The Netherlands, winter 1977/78-2013/14. The National
survey combines all surveys along the North Sea coast.
Win ter nOi led nTotal Oi lrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 87 113 1977/78 77.0 01 1977/78 0.52
1978/79 35 85 1978/79 41.2 01 1978/79 ‐0.15
1979/80 95 142 1979/80 66.9 01 1979/80 0.31
1980/81 1317 1545 1980/81 85.2 01 1980/81 0.76
1981/82 140 188 1981/82 74.5 01 69.0 1981/82 0.46 0.35
1982/83 884 1117 1982/83 79.1 01 69.4 1982/83 0.58 0.36
1983/84 1603 1902 1983/84 84.3 01 78.0 1983/84 0.73 0.55
1984/85 151 276 1984/85 54.7 01 75.6 1984/85 0.08 0.49
1985/86 171 282 1985/86 60.6 01 70.6 1985/86 0.19 0.38
1986/87 61 113 1986/87 54.0 01 66.6 1986/87 0.07 0.30
1987/88 102 153 1987/88 66.7 01 64.1 1987/88 0.30 0.25
1988/89 70 131 1988/89 53.4 01 57.9 1988/89 0.06 0.14
1989/90 87 157 1989/90 55.4 01 58.0 1989/90 0.09 0.14
1990/91 90 151 1990/91 59.6 01 57.8 1990/91 0.17 0.14
1991/92 43 63
1991/92 68.3 01 60.7 1991/92 0.33 0.19
1992/93 66 228 1992/93 28.9 01 53.1 1992/93 ‐0.39 0.05
1993/94 28 62 1993/94 45.2 01 51.5 1993/94 ‐0.08 0.03
1994/95 43 52 1994/95 82.7 01 56.9 1994/95 0.68 0.12
1995/96 12 23 1995/96 52.2 01 55.4 1995/96 0.09
1996/97 23 39 1996/97 59.0 01 53.6 1996/97 0.16 0.06
1997/98 62 138 1997/98 44.9 01 56.8 1997/98 ‐0.09 0.12
1998/99 97 189 1998/99 51.3 01 58.0 1998/99 0.02 0.14
1999/00 129 240 1999/00 53.8 01 52.2 1999/00 0.07 0.04
2000/01 18 44 2000/01 40.9 01 50.0 2000/01 ‐0.16 0.00
2001/02 68 216 2001/02 31.5 01 44.5 2001/02 ‐0.34 ‐0.10
2002/03 96 136 2002/03 70.6 01 49.6 2002/03 0.38 ‐0.01
2003/04 37 64 2003/04 57.8 01 50.9 2003/04 0.14 0.02
2004/05 33 92 2004/05 35.9 01 47.3 2004/05 ‐0.25 ‐0.05

2005/06 7 23 2005/06 30.4 00 45.2 2005/06 ‐0.36 ‐0.08
2006/07 10 71 2006/07 14.1 01 41.8 2006/07 ‐0.79 ‐0.14
2007/08 11 2007/08 0.0 00 27.6 2007/08 ‐0.42
2008/09 8 17 2008/09 47.1 00 25.5 2008/09
2009/10 14 2009/10 0.0 00 18.3 2009/10
2010/11 3 8 2010/11 37.5 00 19.7 2010/11
2011/12 10 257 2011/12 3.9 01 17.7 2011/12 ‐1.39
2012/13 26 2012/13 0.0 01 17.7 2012/13
2013/14 1 4 2013/14 25.0 01 13.3 2013/14 ‐0.48
2014/15 2014/15 00 2014/15

25
Appendix 9 Common Eiders Somateria mollissima
Oil rates of Common Eiders in The Netherlands, winter 1977/78-2013/14. The National survey
combines all surveys along the North Sea coast.
Win ter nOi led nTotal Oi lrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 13 21 1977/78 61.9 00 1977/78
1978/79 10 38 1978/79 26.3 01 1978/79 ‐0.45
1979/80 19 31 1979/80 61.3 01 1979/80 0.20
1980/81 56 103 1980/81 54.4 01 1980/81 0.08
1981/82 63 173 1981/82 36.4 01 48.1 1981/82 ‐0.24 ‐0.03
1982/83 196 458 1982/83 42.8 01 44.2 1982/83 ‐0.13 ‐0.10
1983/84 98 479 1983/84 20.5 01 43.1 1983/84 ‐0.59 ‐0.12
1984/85 110 756 1984/85 14.6 01 33.7 1984/85 ‐0.77 ‐0.29
1985/86 16 236 1985/86 6.8 01 24.2 1985/86 ‐1.14 ‐0.50
1986/87 281 365 1986/87 77.0 01 32.3 1986/87 0.52 ‐0.32
1987/88 658 870 1987/88 75.6 01 38.9
1987/88 0.49 ‐0.20
1988/89 91 590 1988/89 15.4 01 37.9 1988/89 ‐0.74 ‐0.21
1989/90 52 263 1989/90 19.8 01 38.9 1989/90 ‐0.61 ‐0.20
1990/91 54 757 1990/91 7.1 01 39.0 1990/91 ‐1.11 ‐0.19
1991/92 138 533 1991/92 25.9 01 28.8 1991/92 ‐0.46 ‐0.39
1992/93 56 513 1992/93 10.9 01 15.8 1992/93 ‐0.91 ‐0.73
1993/94 25 156 1993/94 16.0 01 15.9 1993/94 ‐0.72 ‐0.72
1994/95 57 588 1994/95 9.7 01 13.9 1994/95 ‐0.97 ‐0.79
1995/96 24 337 1995/96 7.1 01 13.9 1995/96 ‐1.12 ‐0.79
1996/97 33 293 1996/97 11.3 01 11.0 1996/97 ‐0.90 ‐0.91
1997/98 19 162 1997/98 11.7 01 11.2 1997/98 ‐
0.88 ‐0.90
1998/99 37 227 1998/99 16.3 01 11.2 1998/99 ‐0.71 ‐0.90
1999/00 340 6860 1999/00 5.0 01 10.3 1999/00 ‐1.28 ‐0.94
2000/01 12 1344 2000/01 0.9 01 9.0 2000/01 ‐2.05 ‐1.00
2001/02 65 3557 2001/02 1.8 01 7.1 2001/02 ‐1.73 ‐1.11
2002/03 54 722 2002/03 7.5 01 6.3 2002/03 ‐1.09 ‐1.17
2003/04 8 262 2003/04 3.1 01 3.6 2003/04 ‐1.50 ‐1.42
2004/05 12 584 2004/05 2.1 01 3.1 2004/05 ‐1.68 ‐1.50
2005/06 10 342 2005/06 2.9 01 3.5 2005/06 ‐1.52 ‐1.44
2006/07 2 165 2006/07 1.2 01 3.3 2006/07 ‐1.91 ‐1.46
2007/08 1 74 2007/08 1.4 00 2.1 2007/08 ‐1.66
2008/09 1 130 2008/09 0.8 01 1.7 2008/09 ‐2.11 ‐1.77
2009/10 2 92 2009/10 2.2 01 1.7 2009/10 ‐1.65 ‐1.77
2010/11 28 2010/11 0.0 00 1.1 2010/11
2011/12 1 169 2011/12 0.6 01 1.0 2011/12 ‐2.23
2012/13 10 2012/13 0.0 00 0.7 2012/13
2013/14 15 2013/14 0.0 00 0.6 2013/14
2014/15 17 2014/15 0.0 00 0.1 2014/15

26
Appendix 10 Common Scoters Melanitta nigra
Oil rates of Common Scoters in The Netherlands, winter 1977/78-2013/14. The National survey
combines all surveys along the North Sea coast.
Win ter nOi led nTotal Oi lrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 8 10 1977/78 80.0 00 1977/78 0.60
1978/79 144 265 1978/79 54.3 01 1978/79 0.08
1979/80 30 39 1979/80 76.9 01 1979/80 0.52
1980/81 65 83 1980/81 78.3 01 1980/81 0.56
1981/82 160 210 1981/82 76.2 01 73.2 1981/82 0.51 0.44
1982/83 154 194 1982/83 79.4 01 73.0 1982/83 0.59 0.43
1983/84 110 141 1983/84 78.0 01 77.8 1983/84 0.55 0.54
1984/85 98 180 1984/85 54.4 01 73.3 1984/85 0.08 0.44
1985/86 175 238 1985/86 73.5 01 72.3 1985/86 0.44 0.42
1986/87 121 147 1986/87 82.3 01 73.5 1986/87 0.67 0.44
1987/88 1571 1598 1987/88 98.3 01 77.3 1987/88 1.76 0.53
1988/89 56 83 1988/89 67.5 01 75.2 1988/89 0.32 0.48
1989/90 11 19 1989/90 57.9 00 75.9 1989/90 0.14 0.50
1990/91 112 151 1990/91 74.2 01 76.0 1990/91 0.46 0.50
1991/92 70 82 1991/92 85.4 01 76.6
1991/92 0.77 0.52
1992/93 83 143 1992/93 58.0 01 68.6 1992/93 0.14 0.34
1993/94 71 104 1993/94 68.3 01 68.7 1993/94 0.33 0.34
1994/95 155 194 1994/95 79.9 01 73.1 1994/95 0.60 0.44
1995/96 103 139 1995/96 74.1 01 73.1 1995/96 0.46 0.43
1996/97 71 97 1996/97 73.2 01 70.7 1996/97 0.44 0.38
1997/98 24 30 1997/98 80.0 01 75.1 1997/98 0.60 0.48
1998/99 197 244 1998/99 80.7 01 77.6 1998/99 0.62 0.54
1999/00 70 114 1999/00 61.4 01 73.9 1999/00 0.20 0.45
2000/01 10 28 2000/01 35.7 00 66.2 2000/01 ‐0.26 0.29
2001/02 81 178 2001/02 45.5 01 60.7 2001/02 ‐0.08 0.19
2002/03 101 129 2002/03 78.3 01 60.3 2002/03 0.56 0.18
2003/04 15 28 2003/04 53.6 00 54.9 2003/04 0.06 0.09
2004/05 23 44 2004/05 52.3 01 53.1 2004/05 0.04 0.05
2005/06 14 31 2005/06 45.2 00 55.0 2005/06 ‐0.08 0.09
2006/07 2 10 2006/07 20.0 00 49.9 2006/07
2007/08 4 17 
2007/08 23.5 00 38.9 2007/08
2008/09 4 2008/09 0.0 00 28.2 2008/09
2009/10 2 11 2009/10 18.2 00 21.4 2009/10
2010/11 1 5 2010/11 20.0 00 16.3 2010/11
2011/12 1 22 2011/12 4.5 00 13.3 2011/12
2012/13 6 2012/13 0.0 00 8.5 2012/13
2013/14 9 2013/14 0.0 00 8.5 2013/14
2014/15 5 2014/15 0.0 4.9 2014/15

27
Appendix 11 Herring Gull Larus argentatus
Oil rates of Herring Gulls in The Netherlands, winter 1977/78-2013/14. The National survey
combines all surveys along the North Sea coast (Dutch contributions to OSPAR 8 and 9).
Win ter nOi led nTotal Oi lrate%Qual5‐yrmean Logitoil 5‐yrmean
1977/78 49 74 1977/78 66.2 01 1977/78 0.29
1978/79 83 224 1978/79 37.1 01 1978/79 ‐0.23
1979/80 43 146 1979/80 29.5 01 1979/80 ‐0.38
1980/81 291 428 1980/81 68.0 01 1980/81 0.33
1981/82 165 422 1981/82 39.1 01 48.0 1981/82 ‐0.19 ‐0.04
1982/83 232 445 1982/83 52.1 01 45.1 1982/83 0.04 ‐0.08
1983/84 265 644 1983/84 41.1 01 46.0 1983/84 ‐0.16 ‐0.07
1984/85 107 420 1984/85 25.5 01 45.2 1984/85 ‐0.47 ‐0.08
1985/86 67 330 1985/86 20.3 01 35.6 1985/86 ‐0.59 ‐0.26
1986/87 65 218 1986/87 29.8 01 33.8 1986/87 ‐0.37 ‐0.29
1987/88 68 248
1987/88 27.4 01 28.8 1987/88 ‐0.42 ‐0.39
1988/89 63 325 1988/89 19.4 01 24.5 1988/89 ‐0.62 ‐0.49
1989/90 62 291 1989/90 21.3 01 23.6 1989/90 ‐0.57 ‐0.51
1990/91 30 186 1990/91 16.1 01 22.8 1990/91 ‐0.72 ‐0.53
1991/92 41 124 1991/92 33.1 01 23.5 1991/92 ‐0.31 ‐0.51
1992/93 24 183 1992/93 13.1 01 20.6 1992/93 ‐0.82 ‐0.59
1993/94 36 128 1993/94 28.1 01 22.3 1993/94 ‐0.41 ‐0.54
1994/95 31 149 1994/95 20.8 01 22.2 1994/95 ‐0.58 ‐0.54
1995/96 14 156 1995/96 9.0 01 20.8 1995/96 ‐1.01 ‐0.58
1996/97 12 109 1996/97 11.0 01 16.4 1996/97 ‐0.91 ‐0.71
1997/98 13 115 
1997/98 11.3 01 16.0 1997/98 ‐0.89 ‐0.72
1998/99 37 171 1998/99 21.6 01 14.7 1998/99 ‐0.56 ‐0.76
1999/00 40 170 1999/00 23.5 01 15.3 1999/00 ‐0.51 ‐0.74
2000/01 3 180 2000/01 1.7 01 13.8 2000/01 ‐1.77 ‐0.79
2001/02 11 268 2001/02 4.1 01 12.4 2001/02 ‐1.37 ‐0.85
2002/03 25 217 2002/03 11.5 01 12.5 2002/03 ‐0.89 ‐0.85
2003/04 7 115 2003/04 6.1 01 9.4 2003/04 ‐1.19 ‐0.98
2004/05 8 145 2004/05 5.5 01 5.8 2004/05 ‐1.23 ‐1.21
2005/06 6 143 2005/06 4.2 01 6.3 2005/06 ‐1.36 ‐1.17
2006/07 2 84 2006/07 2.4 01 5.9 2006/07 ‐1.61 ‐1.20
2007/08 1 61 2007/08 1.6 01 4.0
2007/08 ‐1.38
2008/09 3 95 2008/09 3.2 01 3.4 2008/09 ‐1.49 ‐1.46
2009/10 1 57 2009/10 1.8 01 2.6 2009/10 ‐1.57
2010/11 59 2010/11 0.0 00 1.8 2010/11 ‐1.74
2011/12 83 2011/12 0.0 01 1.3 2011/12 n.d. ‐1.88
2012/13 2 22 2012/13 9.1 01 2.8 2012/13 ‐1.54
2013/14 1 23 2013/14 4.3 01 3.0 2013/14 ‐1.34 ‐1.50
2014/15 25 2014/15 0.0 01 2.7 2014/15 n.d.

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NIOZ Rapport 2015-4
F
ront cover:
Selection of photos of stranded Com-
mon Guillemots from www.waarne-
ming.nl for the period 1 Nov 2014-30
April 2015. None of the guillemots
depicted are oiled.
Large photo stranded Common Guille-
mot courtesy Jan Andries van Franeker