4th Seminar • Clarion Hotel & Congress, Trondheim • 10-11 April 2013

What have we learnt from the oil-spills from

“Full City” and “Godafoss” ? Arne Follestad and Svein-Håkon Lorentsen

NINA

What have we learnt?

• About seabirds - species and numbers of dead and oiled seabirds - origin (breeding areas) of oiled birds - body condition etc. of oiled birds

• Organizing of - bird counts - collection of dead birds

• The results are summarized in NINA-reports.

About the spills – in different seasons (summer/moulting period vs. winter)

• Full City - Langesund 31.7.2009 - Vestfold and Telemark - NINA-rapport 548

• Godafoss - Hvaler 17.2.2011 - (Østfold), Vestfold, Telemark Aust-Agder and Vest-Agder - NINA-rapport 811

• Both accidents were from coastal boat traffic, and a result of human failure.

NINAs role in the after spill studies

• NINA is not a part of the governmental emergency preparedness (only through the oil companies)

• NINA had no role in organizing collection of data (both for counts/mapping and collection of dead birds)

• NINA was engaged to assess the acute impact on seabirds, and which populations were harmed.

• Now (from 2012) an updated manual for after spill investigations is available.

The seabird studies

• Mapping / counts - After the spills - SEAPOP – overall mapping and monitoring • Assessing numbers of dead and oiled seabirds - Counts in the field - Post mortem investigations (degree of oiling, body condition, moult (F.C.) • Breeding areas for killed eiders, from biometrics and ring recoveries

Number of dead birds sent to NINA after Full City and Godafoss

GODAFOSS Species Number %

Eider 215 72,3

Mute Swan 16 5,4

Herring Gull 10 3,4

Red-breasted Merg. 9 3,0

Long-tailed Duck 8 2,7

Common Gull 7 2,4

Velvet Scoter 5 1,7

Herring Gull? 4 1,4

Common Goldeneye 3 1,0

Common Scoter 3 1,0

TOTAL 297

FULL CITY Species Number %

Eider 256 83,9

Herring Gull 8 2,6

Great Cormorant 5 1,6

Greylag Goose 5 1,6

Lesser Black-backed Gull 5 1,6

Fulmar 4 1,3

Velvet Scoter 3 1

Mute Swan 2 0,7

Mallard 2 0,7

Great Black-backed Gull 2 0,7

TOTAL 305

Eiders most severe damaged in both spills

• After Full City and Godafoss mainly Eiders were oiled and died. In addition some other diving ducks, gulls and swans were damaged.

• Only a few Guillemots (2) and razorbill (1) were found after Godafoss, and two Black Guillemot after Full City.

• Other spills, like Stylis in Skagerrak in 1981, have to a much larger degree killed wintering auks.

• What will happen next time ? And where?? • How may SEAPOP contribute in assessing basic information

that can help in evaluating effects on population level – independent on what happens where?

• We may improve our estimates of dead or damaged birds – but, what will be the population effects?

Proportion of oiled eiders in Vestfold following Godafoss

Note that the proportion is based on total numbers (the sexes were not separated during field counts), but oil damage is difficult to detect on females in the field. The total proportion of oiled Eiders could thus have been close to 50 %.

After Full City the proportion of oiled Eiders was close to 25 and 55 % in Telemark and Vestfold respectively.

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5

10

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25

19.2. 20.2. 21.2. 22.2. 23.2. 24.2. 25.2. 26.2. 27.2. 28.2. 29.2. 1.3. 2.3.

Prop

ortio

n of

oile

d in

divi

dual

s in

%

Numbers of dead or oiled birds – based on an assessment of damage

• Full City - Minimum 1300 Eiders died (if all oiled birds died) - Probably between 1500 and 2000 dead Eiders - Minimum 500 dead individuals of other species

• Godafoss - Minimum 1000 Eiders died (if all oiled birds died) - Probably between 1500 og 2000 dead Eiders, but the number could be even higher - Minimum 1000 dead individuals of other species, probably about 1500, included 90 Mute Swans • Origin of Eiders (and Mute Swans): local breeders

SEAPOP: Aerial counts of wintering Eiders in Southern Norway in February 2009

An estimated total of about 45000 Eiders

Population effects on greater gulls after Godafoss – SEAPOP-data

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Svartbak Gråmåke Sildemåke

2009 2010 2011 The number of nests of three gulls species at Hoftøya close to Store Færder, shown as the percentage of the highest number in the three years with counts. Great BBG and Herring Gulls winter in Skagerrak, and had low breeding numbers after Godafoss. Lesser BBG do not winter in Skagerrak, and had no change after Godafoss. But NB: Few sites.

Great BBG Herring G Lesser BBG

Breast muscle on a male Eider with moderate bode condition (left). This bird got a body condition index of 5, on a scale from 0 to 9. As a comparison the breast muscle and lack of subcuta-neous fat on a lean Eider female is shown (right). This bird got a body condition index of 0. One of several adult Mute Swans with plenty of sub-cutaneous fat (after Goda-foss). This bird got the highest score - 9 - on the body condition index. Several juvenile swans, however, had a very low score.

How was the investigations organized – from our point of view?

• Full City – poor planning from the start, few systematic counts and mapping, a lot of information may have been lost. This was the case for both Vestfold and Telemark.

• Godafoss – Vestfold and Telemark had a better organization (had experience from Full City), while it was poor for the two Agder counties (who lacked this experience).

• This caused a larger time consume – and thus overall costs – for us to systematize data and to determine the impact on seabirds in both spills.

• Counts of Eiders didn’t separate between sexes – more difficult to estimate the proportion of oiled birds.

Are search routines for oiled or dead birds good enough?

• IUA searches mainly in the intertidal zone when assessing stranded oil.

• What do they find then? Only those birds most severely damaged?

• Wounded or sick birds will some times walk further inland to find shelter, as in the higher vegetation.

• In other field work on some islands, some time after the oil spill from Godafoss, remains from several dead birds were found. Were they oiled birds from the spill, either being able to go there by them selves, or brought there by gulls or crows?

Summary – what have we learnt?

• Important to start counts/mapping and search for dead birds a.s.a.p., before the oiled birds dies and disappear.

• We were able to handle the dead birds from Full City and Godafoss through post mortem – what should be prioritized in case of a much higher number of dead birds found?

• We have built up data-series on biometry, age-composition, body condition etc.

• Important to have exercises on oil spills, such as IUA, SNO and others can act rapid and adequate when the next spill comes.

• Important to coordinate activities, to avoid the seabirds are scared into oiled areas.

Questions?

Where to go next?