Verstrikkingen van zeevogels in zwerfvuil en vistuig, 1970-2007. Sula 21(2): 88-92.

The effects of marine litter, debris and fishing gear on marine wildlife has been described before and so has the percentage of entangled specimens of the total number of birds and marine mammals found dead during beached bird surveys received attention in previous publications. The present analysis should be seen as an update. Since 1970, 215,347 more or less complete carcasses of birds were checked (85% of the total number of birds found dead), and 513 of these were entangled in litter or fishing gear (0.2%). Half these birds were Northern Gannets and Herring Gulls (Tabel 1). Ranked after the proportion of entangled casualties of the total number of birds found (Tabel 2), two coastal species (Great Black-backed Gull, Red-throated Diver, Great Cormorant, and Herring Gull) and one pelagic seabird (Northern Gannet) formed the top-5. Since 1979, the period with best data, the level was roughly stable at 0.31 ± 0.13% per annum (mean ± SD; 405 casualties out of a total of 142,030 birds found, only including the 12 species listed in Table 1), followed by a rather higher level of 0.75 ± 0.10% per annum during 2004-2007 (same selection of species, 74 casualties out of 10,181 birds recorded during beached bird surveys). For the analysis we did not (again) check the types of materials responsible for most cases of entanglement, but it is certain that nylon fish lines, pieces of fishing nets and all other kinds of ropes and lines, often from fisheries activities, were mostly to blame. The recent increase is both remarkable and unexplained and certainly would deserve future attention and further research.