Plastics and seabirds

Ingestion of plastic particles and entanglement with plastic are two major impacts that impose a direct threat to seabirds. In Belgium there is ample knowledge of the impact of plastics on seabirds. In the As-Made study we try to fill this gap at three different levels. In the first place we will analyse the long-term database on beached bird surveys hosted by the Research Institute for Nature and Forest (INBO) for entanglement of birds. Next we will use the data collected in the Save The North Sea Project (in cooperation with Imares-Texel) to analyse the origins of the plastics found in stomachs of beached Fulmars. Finally a methodological study is set up to see whether it is possible to count plastics at seas from a steaming ship, similar to the methodology used to count seabirds.


Entanglement of beached birds


During dedicated surveys along the Belgian shoreline 10,156 birds covering more than a 100 species have been found beached since the winter 1991/1992. The most frequently encountered species is the Common Guillemot, representing one out of three beached birds found, followed by Herring Gull, Oystercatcher, Northern Fulmar, Kittiwake and Razorbill.


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Out of the 10,156 beached birds 56 were entangled (0.6%). The species distribution of the entangled birds greatly differed from that of beached birds, indicating strong species specific differences in sensitivity to entanglement. Northern Gannets tend to be the most impacted: representing one third of the 56 entangled birds. Almost one out of ten beached Northern Gannets was found entangled, showing the high sensitivity of this species. Amongst the 13 entangled species, four deep diving seabird species (Northern Gannets, Great Cormorant, Red-throated Diver and Great Crested Grebe) were all found entangled in more than 1% of the collected individuals of the same species, confirming the results of other European studies.




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Getting into the details of entanglement, almost 75% of all birds were entangled in fishing gear, either fishing rope, fishing lines, pieces of nets or hooks. Also wrappings and other packing materials (especially six-packs) and even plastic drinking cups caused mortality among seabirds.

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Plastics in Fulmar stomachs

Fulmars are known to hold large quantities of plastic particles in their stomach. Within the North Sea an average stomach of a Fulmar contains an amount of plastic equivalent to a bread box full when projected to human proportions. Within the AS-MADE project the stomachs of 174 Fulmars found dead along the Belgian coastline between 2002 and 2006 were analysed. No less than 95% of all collected Fulmars had plastic in their stomach; 94% of the individuals had user plastics (e.g. plastic bags, foil, thread pieces, nylon ropes, parts of polystyrene, fragments of plastic bottles, party balloons and elastics) in their stomach and 56% contained industrial pellets (i.e. small pellets of approximately 0.5 mm in diameter used as a semi-manufactured product in the plastic industry).


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The plastic loads found in Fulmars stranded in Belgium are more or less comparable to other parts of the North Sea, although the southern North Sea as a whole seems more polluted than other parts of the North Sea. Our analysis indicates that especially the proportion of industrial plastics found in the Belgian birds is much higher than in other parts of the North Sea.


In order to qualify the North Sea “clean” of plastics, less than 10% of the Fulmars should contain more than 0.1 gram of plastic in their stomachs. This is the Ecological Quality Objective that is proposed to OSPAR to serve as an indicator for a healthy marine ecosystem. Of the birds found in Belgium 51% are above the limit of 0.1 gram of plastic, indicating that we have a long way to go.


Density of the floating litter offshore

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This part of the As-Made study aimed to develop a methodology to determine the amount of litter floating litter at the Belgian part of the North Sea. For that reason floating litter was counted during ship-based surveys simultaneously to counts of seabirds. On the 2200 km² covered by the surveys from February 2009 to July 2010 in total 1232 pieces of floating plastic were counted, giving an average density of  0.56 plastic items per km². This figure learns us that the Belgian part of the North Sea contains as many floating plastic particles as there are Razorbills swimming at its surface.


About half of the floating material consisted of sheet like plastic: plastic bags and foils. One fifth was hard plastics: plastic bottles, cans, buoy, plastic cups, fishing box….No less than 13% of the observed floating items were inflated party balloons and another 3% fishing nets, lining and rope. Especially the latter category has a direct impact on entanglement of seabirds.

 

 


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