t PERGAMON Marine Pollution l3LIIletifl 44 (2002 294 1295 PZUJTllJ Seabirds and floating plastic debris Gerhard C. Cadée \VWV .eIsvier.cont/1ocate/marpo1huI Abstract \(iII(’r/cI,its In fnh!n for 5oct Rosocioi, 1’. ). Box 5V. / 00 113 Den Bin ic.vehVe t/ier/cnuf.c 80% of floating plastic debris freshly vashed ashore on a Dutch coast showed peckmarks made by birds at sea. They either mistake these debris for cuttlebones or simply test all floating objects. Ingestion of plastic is deleterious for marine organisms. Ii is urgent to set measures to plastic litter production. © 2002 Elsevier Science Lid All riehis reserved. Keiii,ccclv: Plaatjes: FuImar: \orth Sea: S7icc Floating plastic debris occur in the oceans woridwide in ever-increasing amounts (Wilber, 1987; Coe and Rogers, 1997; Walker et al., 1997; Derraik, in press). Their mainly negative effects on marine life in general and on seabïrds in particular have attained wide interest (Laist. 1997). Seabirds ingest considerable aniounts of floating marine litter including plastics (Van Franeker. 1985: Ryan. 1987). Based on studies of stomach con tents. Van Franeker and Mei jboom (2002) conclude that the Northern Fulmar ingests almost e’ erything floating on the sea surface. During studies of cuttiebones stranded on the North Sea beach of the Island of Texel, the Netherlands, in 1996 (Cadée, l997a,b), 1 observed that these often showed peckmarks made by birds. some made by Northern Fulmars ( Eig. 1 a), Cuttiebones are the inter— nal. partlv air—filled s1iells’ of the cephalopod 5 7/c/ of— ficinalfv: thev are used in regulating the animal’s buovancv. Thev are liherated in open sea from deca ing Sepiu and eau float for several months. In somevears cuttiebones wash ashore on the [)utuh eoasi in large quantitics in August/Septemher. after the mating season of Sepin. when many specimens die, and again al the start of the winter period when Sepio leaves the North Sea again. Incidence of peckmarks in cuttlebones varied in 1996: 30 of the cuttlebones showed peckmarks n thosc stionjed en the %ort 1 Sen heach of the isle of marks in those stranded on Texel in August/September 1996 (n = 1030). Birds need calcium carbonate for their skeleton and an increased amount during the egg for mation period (see e.g. Graveland et al., 1994 for pas serine birds). Pecking of cuttlebones might be to fulfill this demand---—for the same reason cuttlebones are used for birds in captix ity. During one of the beach surveys for cuttlehones. 1 also collected all styrofoam and other spongious plastic macro debris (>3 cm. Rihic et al.. 1992) recently washed ashore in the latest high water line. 1 stopped after 1 had sampled 100 particles; 80% of these debris showed also peckmarks (see Fig. lb). Fulmars and other seabirds might mistake these floating plastic debris for cuttie bones and ingest parts of it, Another possibility ïs that hoth drifting plastic debris and cuttlehones are onlv ‘tested’ bv the seabirds. The presence of mans surhcial ‘bites’ seems to support this latter suggestion. bui the fact that Van Franeker and Meijboom (2(02) did ob serve also spong plastic particles in the stomach of Eulmars indicates that they also rio ingest ilastic. may he h\ mistaking it tot cuttlehones. This high incidence of peckmarks in floating plas— ties tallies with the fact that almost 100% of the Fu1— mars tested hy Van Franeker and Meijhoom (2002) contained plastic in their stomach. The now wcll-known deleierious eflects of ingcsied plasiics en seabirds and othe marine- oreonisms t Rvan. : i.aist. r)7 indo hee oh .. .o*. s of me .tt.t1 5—e1t.o\ •e1’.H:t — tron . er 2t)tt2 et nee t:] rt:r1i s :.