Wageningen IMARES is een samenwerkingsverband tussen Wageningen UR en TNO

IMARESEcological sensitivity in the Netherlands part of the North Sea          J.A. van Dalfsen

Ecological Risks

Main aspects of oil pollution:- risk to ecological vulnerable areas- risk to birds- risk to organisms in the water column, the seabed and shores

What is sensitive or vulnerable?

Fishing areas & Benthos diversity

Important sea bird areas at the North Sea (Skov et al.)

Avg/year Ranked

according to densities

Risk to Birds Different species vary in terms of their sensitivity

to oil The sensitivity of seabirds depends largely on

behavioural characteristics and species-specific differences in terms of the risk of exposure to oil

Seabirds are particularly vulnerable to oil because even the smallest amount destroys the insulating and waterproofing abilities of their feathers

TernPuffinGuillemot

Oil Vulnerability Indices

Factors used by Camphuysen (1989) in evaluating an oil vulnerability index for birds in the southern North Sea

Range Behaviour Exposure

1 - Breeding 5 - Roosting 11 - Spring2 - Migration 6 - Foraging 12 - Summer3 - Wintering 7 - Reaction to disturbance 13 - Autumn4 - Marine orientation 8 - Flocking 14 – Winter

9 - Nesting density10 - Specialisation

The scale of vulnerability of seabirds depends not only on numbers present but also on behavioural and other characteristics of the species involved. An Oil Vulnerability Indices assesses these characteristics and species-specific sensitivity to oil pollution

Most sensitive seabird families (Camphuysen, 1989) Mean oil vulnerability index (OVI) scores for seabird

families of the North Sea

Family Mean OVI Min MaxAuks 77.2 65 - 86Divers 66.3 65 - 68Cormorants and shags 66.0 59 - 73Gannets and boobies 65.0 65 - 65Sea ducks 64.2 45 - 75Petrels and shearwaters 59.2 47 - 65Diving ducks 58.0 58 - 58Grebes 53.3 46 - 58Storm-petrels 50.3 49 - 54Terns 47.9 46 - 51Gulls 45.1 36 - 66Skuas 42.6 36 - 58Phalaropes 38.0 37 - 39

Vulnerability to Oil spill

Time and place

(UK Atlas)

Azs1991p3pred

0.0 - 1.4

1.5 - 3.0

3.1 - 4.6

4.7 - 6.0

6.1 - 7.1

7.2 - 8.4

8.5 - 10.1

10.2 - 12.0

12.1 - 14.9

Azs1992p3pred0.0 - 1.7

1.8 - 4.0

4.1 - 6.6

6.7 - 8.7

8.8 - 10.7

10.8 - 13.0

13.1 - 15.2

15.3 - 17.0

17.1 - 28.5

Azs1994p3pred0.0 - 0.4

0.5 - 0.9

1.0 - 1.3

1.4 - 1.8

1.9 - 2.3

2.4 - 2.9

3.0 - 3.7

3.8 - 4.5

4.6 - 5.8

Azs1996p3pred-0.1 - 2.1

2.2 - 4.8

4.9 - 6.9

7.0 - 9.0

9.1 - 11.3

11.4 - 14.0

14.1 - 16.9

17.0 - 20.8

20.9 - 25.8

Azs1997p3pred

-0.1 - 0.8

0.9 - 1.6

1.7 - 2.1

2.2 - 2.8

2.9 - 3.7

3.8 - 5.0

5.1 - 7.1

7.2 - 9.8

9.9 - 14.4

Azs1998p3pred-0.1 - 1.0

1.1 - 2.4

2.5 - 3.8

3.9 - 5.7

5.8 - 7.9

8.0 - 10.4

10.5 - 13.1

13.2 - 15.9

16.0 - 20.4

Azs2000p3pred-14.6 - 2.1

2.2 - 5.8

5.9 - 9.5

9.6 - 15.1

15.2 - 26.2

26.3 - 44.8

44.9 - 72.6

72.7 - 136.5

136.6 - 222.7

Azs1999p3pred0.0 - 0.4

0.5 - 1.0

1.1 - 1.5

1.6 - 1.8

1.9 - 2.2

2.3 - 2.4

2.5 - 2.7

2.8 - 3.0

3.1 - 3.2

Azs2001p3pred

-1.5 - 2.8

2.9 - 5.2

5.3 - 8.1

8.2 - 12.0

12.1 - 16.5

16.6 - 20.7

20.8 - 25.2

25.3 - 31.2

31.3 - 46.6

RIKZ

Natural variation 9 years of December countings

Auk - Guillemot

Data density

Information covers not the total DCS

Aug - Sep Oct - Nov

Dec - Jan Feb - Mar

Apr - May Jun - Jul

common scoter, coastal gullsguillemot, kittiwake, fulmar, gbbgkittiwakefulmar, gannetgannet, gbb gull, razorbilllittle gull, common gull

eider, common scotereider, scoters, coastal gullsguillemot, kittiwake, fulmar, gullskittiwake, gbb gull

fulmargbb gull, fulmar, razorbillcommon scoter, common gullrazorbill

common scoter, eidercoastal gulls, kittiwakefulmar, kittiwake, guillemot, gullskittiwake, gbb gull, razorbillgannet, guillemotrazorbill, gannet

coastal gulls, common scotercoastal gulls, ternscommon scoterfulmar, kittiwake, guillemot, lbbg

guillemotgannet

coastal gulls, terns, scoterslbb gull, fulmarfulmar, kittiwake, guillemotherring & lbb gull, fulmarkittiwake, gannet, guillemotguillemotgannet

coastal gulls, ternscoastal gullscoastal gulls, terns, eiderscommon scoterfulmar, guillemotguillemotgannetcommon tern, cormorant

Aug - Sep Oct - Nov

Dec - Jan Feb - Mar

Apr - May Jun - Jul

common scoter, coastal gullsguillemot, kittiwake, fulmar, gbbgkittiwakefulmar, gannetgannet, gbb gull, razorbilllittle gull, common gull

eider, common scotereider, scoters, coastal gullsguillemot, kittiwake, fulmar, gullskittiwake, gbb gull

fulmargbb gull, fulmar, razorbillcommon scoter, common gullrazorbill

common scoter, eidercoastal gulls, kittiwakefulmar, kittiwake, guillemot, gullskittiwake, gbb gull, razorbillgannet, guillemotrazorbill, gannet

coastal gulls, common scotercoastal gulls, ternscommon scoterfulmar, kittiwake, guillemot, lbbg

guillemotgannet

coastal gulls, terns, scoterslbb gull, fulmarfulmar, kittiwake, guillemotherring & lbb gull, fulmarkittiwake, gannet, guillemotguillemotgannet

coastal gulls, ternscoastal gullscoastal gulls, terns, eiderscommon scoterfulmar, guillemotguillemotgannetcommon tern, cormorant

Aug - Sep Oct - Nov

Dec - Jan Feb - Mar

Apr - May Jun - Jul

Bird value map for the DCS

Based on a Ecovalue per species Multiplied with abundance per time period of 2 months

Region Marine Estuary

Habitat Water surface, water column, inter-tidal, sub-tidal, Terrestrial,

Sub-habitat water surface, shallow water, deep water, sandy beach,

dunes, hard substrate, salt marsh, mud flats, reefs & beds,

Type of organism Birds, mammals, fish, plankton, fish, benthos,

vegetation, insects

Risk to the water column, sea bed and land

3°E

3°E 4°E

4°E

5°E

5°E

6°E

6°E

7°E

7°E

52°N

53°N

54°N

55°N

500000 600000 700000

570

000

058

00

000

590

000

060

00

000

610

000

0

Voorgestelde gebieden metbijzondere ecologische waarden

Gebieden genoemd in de Nota Ruimte

Aanvullende gebieden

Duitse gebieden

Vogel- en Habitatrichtlijn gebieden

PKB-gebied waddenzee

Datum: ED50 UTM projectie 31N

Habitats characteristics are mostly physical (MESH), Whereas sensitivity depends on species

Risks to the water column and sea bed Ecotox effects on plankton, benthos & fish Physical stress Reduced feeding efficiency of organisms

Areas of different ecological value, withspecies having different sensitivities to oil

Some habitats depend on certain key species (bio-engineers)

Recovery time

Sensitivity and the use of dispersants

Main aspects of oil pollution:- risk to ecological vulnerable areas- risk to birds- risk to organisms in the water column or on the seabed

Does this change when dispersants are used?

Ecological sensitivity and the use of Dispersants Change from water surface to the water column andsea bed: Increased concentration hydrocarbon components Increased bio-availability of components of oil &

dispersants Toxic effect Physical effect

(Depending type/amount of oil, water depth, water temperature, turbulence etc.)

Change of sensitive areas and species enters more easily in the food web

‘Marine’ food web

Copepod production

Sand eel as example

Feeds on copepods, worms and planktonIt important food for different birds e.g.Terns

What is the fate of dispersed oil and what are the risk to this food chain?Are there long term or chronic effects to expect?

Noorse Stern

Different species and areas vary in terms of their sensitivity to oil

The sensitivity of sea areas depends mainly on the numbers and behaviour of sensitive (seabird) species occurring there

The amount of oil spilled is less important than the season in which spillage occurs, and the location of that spillage.

A small amount of oil in a crucial seabird habitat can be far more deadly than a large oil spill elsewhere.

Information on bird species presence on a European or DCS scale is far from complete. This lack in information prevents a good decision process on the use of dispersants

Conclusions

Conclusions II There is poor environmental baseline data for

comparing the status of a situation prior to and after oiling

The effect of oil hydrocarbons thru the food web is still difficult to quantify

There is a lack in integrated population or ecosystem studies compared to single species studies

1. Collection and compiling information on the ecosystem values of the DCS.

2. Natural variation in ecosystems stresses the need for efficient monitoring

3. Long-term, chronic sub-lethal impacts of oil pollution need to be studied, including food web studies

4. Evaluation of the sensitivity of the ecosystem components on oill spills detergents

5. Produce adequate information for the decisions to safeguard the most valuable areas and populations in the case of an oil spill

Conclusions III what is needed?

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