data for the pelagic areas (see Chapter 6.2). These estimates are considered to be conservative, as they do not take into account turnover rates. A significant proportion of seabird breeding populations is bound to the colonies during the breeding season therefore recorded number of birds at sea is lower than the actual number of birds using the marine areas. Additionally, the estimated seabird numbers using migratory bottlenecks are based on direct counts and not on their extrapolation to the entire day or even the entire migration period. Furthermore, the seasonal stability of the geographical boundaries of the candidate sites has been validated by comparing boundaries deduced from recorded data and from models of different years.
6.4 Final delineation boundaries and identification of marine IBAs Candidate marine IBAs for each species meeting IBA criteria were merged to produce final marine IBA boundaries. Overlapping areas for different species and different types of marine IBA sites (Chapter 4) were combined to form a single marine
IBA (Figure 6.19). When the resulting marine IBA was larger than that of individual trigger species, the seabird numbers present in this greater area were recalculated over the entire area of the marine IBA. The boundaries of the marine IBAs were delineated in such a way so as to allow for easy identification on-site. In marine IBAs consisting exclusively of seaward extensions for different species, these seaward extensions were merged to form a union. On the other hand, boundaries of pelagic areas and migratory bottlenecks were delimited by simple polygons which optimally enclose its constituting parts. It should be noted that areas occupied by man-made structures, such as ports, have not been excluded by the delineation process. However, if considered necessary they should be appropriately excluded from the future corresponding SPAs for management purposes. Candidate marine IBAs in Greece have been submitted to the BirdLife Secretariat in order to be checked and validated.
TURKEY
Legend Final marine IBA boundaries Calonectris diomedea * *** ** ** ** **
0
2
4
6
8 nm
50
* * *
Puffinus yelkouan Larus audouinii Phalacrocorax aristotelis
100
200
500
1000
2000
3000
4000
5000
>5000 m depth
Figure 6.19: Marine IBA GR160 for Audouin’s Gull, Mediterranean Shag, Cory’s Shearwater and Yelkouan Shearwater 68