Plastic ingestion by juvenile polar cod (Boreogadus saida) in the Arctic Ocean

Susanne Kühn,Bernike Van Werven,Marion Egelkraut-Holtus,Hauke Flores,Jan A Van Franeker,Melanie Bergmann,Mine B Tekman,Fokje L Schaafsma

doi:10.1007/s00300-018-2283-8

Susanne Kühn, Bernike Van Werven + Show 6 more

Open Access

https://doi.org/10.1007/s00300-018-2283-8

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Abstract

One of the recently recognised stressors in Arctic ecosystems concerns plastic litter. In this study, juvenile polar cod (Boreogadus saida) were investigated for the presence of plastics in their stomachs. Polar cod is considered a key species in the Arctic ecosystem. The fish were collected both directly from underneath the sea ice in the Eurasian Basin and in open waters around Svalbard. We analysed the stomachs of 72 individuals under a stereo microscope. Two stomachs contained non-fibrous microplastic particles. According to µFTIR analysis, the particles consisted of epoxy resin and a mix of Kaolin with polymethylmethacrylate (PMMA). Fibrous objects were excluded from this analysis to avoid bias due to contamination with airborne micro-fibres. A systematic investigation of the risk for secondary micro-fibre contamination during analytical procedures showed that precautionary measures in all procedural steps are critical. Based on the two non-fibrous objects found in polar cod stomachs, our results show that ingestion of microplastic particles by this ecologically important fish species is possible. With increasing human activity, plastic ingestion may act as an increasing stressor on polar cod in combination with ocean warming and sea-ice decline in peripheral regions of the Arctic Ocean. To fully assess the significance of this stressor and its spatial and temporal variability, future studies must apply a rigorous approach to avoid secondary pollution.

Highlights

Debris ingestion by a wide range of marine organisms has been demonstrated in various studies from all over the world
Our best estimate on the impact of aerial fibre contamination during laboratory analysis are the averages found in controls of groups D and E. This first study of potential microplastic ingestion by polar cod sampled over a large part of the Central Arctic Ocean (CAO) and partly dwelling in the barely accessible under-ice habitat indicates that polar cod probably do ingest microplastics, albeit at very low frequencies
Our overall result of 2.8% frequency of occurrence of ingested non-fibrous microplastic particles among 72 polar cod is similar to the level of plastic ingestion observed in the full gastrointestinal tracts of Atlantic cod (Gadus morhua) from Newfoundland, where 2.4% of 205 fish analysed contained non-fibrous plastic (Liboiron et al 2016)

Summary

Introduction

Debris ingestion by a wide range of marine organisms has been demonstrated in various studies from all over the world. Marine debris and in particular plastics have been found in all ocean basins of the world (Barnes et al 2009; Eriksen et al 2014; Galgani et al 2015; Van Sebille et al 2015). Recent studies have shown that plastic debris has reached the Arctic oceanic and sea-ice environments, and its wildlife (Schulz et al 2010; Obbard et al 2014; Lusher et al 2015; Trevail et al 2015b; Bergmann et al 2017a, c; Buhl-Mortensen and Buhl-Mortensen 2017; Cózar et al 2017). A suggested presence of an accumulation area in the Barents Sea (Van Sebille et al 2015) was supported by Cózar et al (2017) with recent field data and additional modelling indicating a peak accumulation of plastic in the vicinity of Svalbard and Novaya

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