Article pubs.acs.org/est
Plastic in North Sea Fish Edwin M. Foekema,*,† Corine De Gruijter,†,§ Mekuria T. Mergia,†,‡ Jan Andries van Franeker,∥ AlberTinka J. Murk,‡ and Albert A. Koelmans†,§ †
IMARES Wageningen UR, Department Experimental Ecology, P.O. Box 57, 1780 AB Den Helder, The Netherlands Wageningen University, Division of Toxicology, Tuinlaan 5, 6703 HE Wageningen, The Netherlands § Wageningen University, Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, P.O. Box 47, 6700 AA Wageningen, The Netherlands ∥ IMARES Wageningen UR, Department Ecosystems, P.O. Box 167, 1790 AD Den Burg (Texel), The Netherlands ‡
S Supporting Information *
ABSTRACT: To quantify the occurrence of ingested plastic in fish species caught at different geographical positions in the North Sea, and to test whether the fish condition is affected by ingestion of plastics, 1203 individual fish of seven common North Sea species were investigated: herring, gray gurnard, whiting, horse mackerel, haddock, atlantic mackerel, and cod. Plastic particles were found in 2.6% of the examined fish and in five of the seven species. No plastics were found in gray gurnard and mackerel. In most cases, only one particle was found per fish, ranging in size from 0.04 to 4.8 mm. Only particles larger than 0.2 mm, being the diameter of the sieve used, were considered for the data analyses, resulting in a median particle size of 0.8 mm. The frequency of fish with plastic was significantly higher (5.4%) in the southern North Sea, than in the northern North Sea above 55°N (1.2%). The highest frequency (>33%) was found in cod from the English Channel. In addition, small fibers were initially detected in most of the samples, but their abundance sharply decreased when working under special clean air conditions. Therefore, these fibers were considered to be artifacts related to air born contamination and were excluded from the analyses. No relationship was found between the condition factor (size−weight relationship) of the fish and the presence of ingested plastic particles.
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INTRODUCTION
Large objects of plastic can pose a threat to marine organisms by entanglement, whereas smaller items are available for ingestion by many marine organisms including fish. The occurrence of plastic debris in fish was noticed as early as 1972 by Carpenter et al.17 More recently, plastic particles were encountered in different species.18−21 It is suggested that fish ingest mainly those plastic fragments that have similar color and shape as their food particles17,18 as is also the case with sea turtles for which plastic bags resemble jelly fish.1 Because of the wide variety of colors, sizes, and shapes of plastic fragments, they will probably mimic a wide range of natural food sources.1 Several studies described the presence of ingested plastics in fish (refs 17−21, and 22−24 but only one25 studied plastic in North Sea fish. The North Sea is among the seas most intensively used for fishing and shipping, so plastic waste is to be expected. Monitoring studies with Northern Fulmars revealed ingested plastics in 95% of these birds following a clear spatial pattern. Northern Fulmars in the Channel area had the highest plastic burden, and this gradually decreased in northward direction.26 For fish, a relationship between the
The amount of marine litter is ever increasing, and consists up to 60 to 80% out of plastics.1 Accumulation of plastic is therefore recognized as one of today’s major marine water quality problems,2 and it is assumed that the amount disposed will increase due to land-based sources as well as to maritime activities.3 As most plastic debris is buoyant,1,4 it can be transported by currents and winds, resulting in a widespread occurrence across the oceans.5,6 The distribution is very patchy, as it is affected by local wind and current conditions, coastal geography, and by the way plastic enters the system.3 Plastics are very persistent 5 but are known to degrade into smaller pieces.7,8 Degradation in water is particularly slow due to reduced UV exposure and lower temperatures in the water compared to land.3,9 Therefore, especially low density plastic types that float can be broken down by UV−B radiation and become brittle, and break down into microplastics (defined as
