Two forage fishes as potential conduits for the vertical transfer of microfibres in Northeastern Pacific Ocean food webs

We assessed the potential role played by two vital Northeastern Pacific Ocean forage fishes, the Pacific sand lance (Ammodytes personatus) and Pacific herring (Clupea pallasii), as conduits for the vertical transfer of microfibres in food webs. We quantified the number of microfibres found in the stomachs of 734 sand lance and 205 herring that had been captured by an abundant seabird, the rhinoceros auklet (Cerorhinca monocerata). Sampling took place on six widely-dispersed breeding colonies in British Columbia, Canada, and Washington State, USA, over one to eight years. The North Pacific Ocean is a global hotspot for pollution, yet few sand lance (1.5%) or herring (2.0%) had ingested microfibres. In addition, there was no systematic relationship between the prevalence of microplastics in the fish stomachs vs. in waters around three of our study colonies (measured in an earlier study). Sampling at a single site (Protection Island, WA) in a single year (2016) yielded most (sand lance) or all (herring) of the microfibres recovered over the 30 colony-years of sampling involved in this study, yet no microfibres had been recovered there, in either species, in the previous year. We thus found no evidence that sand lance and herring currently act as major food-web conduits for microfibres along British Columbia’s outer coast, nor that the local at-sea density of plastic necessarily determines how much plastic enters marine food webs via zooplanktivores. Extensive urban development around the Salish Sea probably explains the elevated microfibre loads in fishes collected on Protection Island, but we cannot account for the between-year variation. Nonetheless, the existence of such marked interannual variation indicates the importance of measuring year-to-year variation in microfibre pollution both at sea and in marine biota.

J. M. Hipfner, M. Galbraith, S. Tucker and al., Environmental Pollution, Volume 239, August 2018, Pages 215-222

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Marine debris boost in juvenile Magellanic penguins stranded in south-eastern Brazil in less than a decade: Insights into feeding habits and habitat use

The Magellanic penguin (Spheniscus magellanicus) is a marine sentinel for the southern Atlantic Ocean that is a proxy of environmental quality. The presence of marine debris (macro-debris) in the stomach contents of emaciated juvenile penguins stranded from 21°S to 23°S was compared at different times (2000 and 2008), and the debris ingestion pathway was determined. The frequency of marine debris in the stomachs doubled in less than a decade, and flexible plastics remained the main ingested item over time (68–70%). The pelagic octopus, Argonauta nodosa, which inhabits the sea surface, was the most important prey species recovered in the stomach contents. The poor physical condition of the penguins that reach the northern migration limit (study area) reduces the diving capacity of the animals and increases their vulnerability to debris ingestion. Considering their preferred prey and physical condition, we conclude that the penguins likely ingested the marine debris in surface waters.

Ana Paula Madeira Di Beneditto, Salvatore Siciliano, Marine Pollution Bulletin, Volume 125, Issues 1–2, 15 December 2017, Pages 330-333

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Plastic ingestion by Newell’s (Puffinus newelli) and wedge-tailed shearwaters (Ardenna pacifica) in Hawaii

The ingestion of plastic by seabirds has been used as an indicator of pollution in the marine environment. On Kaua‘i, HI, USA, 50.0 % of Newell’s (Puffinus newelli) and 76.9 % of wedge-tailed shearwater (Ardenna pacifica) fledglings necropsied during 2007–2014 contained plastic items in their digestive tract, while 42.1 % of adult wedge-tailed shearwaters had ingested plastic. For both species, the frequency of plastic ingestion has increased since the 1980s with some evidence that the mass and the number of items ingested per bird have also increased. The color of plastic ingested by the shearwaters was assessed relative to beach-washed plastics by using Jaccard’s index (where J = 1 complete similarity). The color (J = 0.65–0.68) of items ingested by both species, and the type ingested by wedge-tailed shearwaters (J = 0.85–0.87), overlapped with plastic available in the local environment indicating moderate selection for plastic color and type. This study has shown that the Hawaiian populations of shearwaters, like many seabird species, provide useful but worrying insights into plastic pollution and the health of our oceans.

Elizabeth C. Kain, Jennifer L. Lavers, Carl J. Berg, André F. Raine, Alexander L. Bond, Environmental Science and Pollution Research, December 2016, Volume 23, Issue 23, pp 23951–23958

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Nests of the brown booby (Sula leucogaster) as a potential indicator of tropical ocean pollution by marine debris

Seabirds collect debris primarily nearby breeding sites, and thus they may be used to monitor these pollutants in the ocean. This study aimed to investigate the prevalence of marine debris used as nesting materials by the brown booby (Sula leucogaster) and to test the species selectivity to debris type and color in two coastal islands of Brazil. We found marine debris in 61% of the brown booby nests on both islands. Fishing gear and hard plastic were the most frequent types of debris. Higher prevalence of fishing gear was found on the island with greater fishery activity. Similarly, hard plastic was the most frequent type of debris in nests and adjacent beach environment. The frequency of debris in brown booby nests can be a potential indicator of the abundance of specific items in surrounding marine waters. Monitoring debris in brown booby nests in a long-term may provide a better understanding of the species selectivity for specific debris. Furthermore, the impacts of debris in seabird nests at population level remain an overlooked threat that may reduce the quality of nesting habitats. We showed that brown booby nests are widely impacted by marine debris and that these organisms are exposed to this form of pollution from the beginning of their life.

Davi Castro Tavares, Leonardo Lopes da Costa, Danilo Freitas Rangel, Jailson Fulgencio de Moura, Ilana Rosental Zalmon, Salvatore Siciliano, Ecological Indicators, Volume 70, November 2016, Pages 10–14, Navigating Urban Complexity: Advancing Understanding of Urban Social – Ecological Systems for Transformation and Resilience

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A study of wrecked Dovekies (Alle alle) in the western North Atlantic highlights the importance of using standardized methods to quantify plastic ingestion

Quantification of plastic ingestion across a range of seabirds is required to assess the prevalence of plastics in marine food webs. We quantified plastic ingestion in beached Dovekies (Alle alle), following a wreck in Newfoundland, Canada. Of 171 birds, 30.4% had ingested plastic (mean 0.81 ± 0.30 SE pieces per bird, mass 0.005 ± 0.002 SE g per bird). Most plastics were fragments of polyethylene and polypropylene. Surprisingly, 37% were burned or melted, indicating a previously unreported source of ingested plastics (incinerated waste). We found no relationship between plastic ingestion and age, sex or body condition. By comparing our results with a similar nearby study, we illustrate the need for researchers to adopt standardized methods for plastic ingestion studies. We underline the importance of using histological techniques to reliably identify gastric pathologies, and advise caution when inferring population level trends in plastic ingestion from studies of emaciated, wrecked birds.

Stephanie Avery-Gomm, Michelle Valliant, Carley R. Schacter, Katherine F. Robbins, Max Liboiron, Pierre-Yves Daoust, Lorena M. Rios, Ian L. Jones, Marine Pollution Bulletin, Volume 113, Issues 1–2, 15 December 2016, Pages 75–80

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Marine plastic debris emits a keystone infochemical for olfactory foraging seabirds

Plastic debris is ingested by hundreds of species of organisms, from zooplankton to baleen whales, but how such a diversity of consumers can mistake plastic for their natural prey is largely unknown. The sensory mechanisms underlying plastic detection and consumption have rarely been examined within the context of sensory signals driving marine food web dynamics. We demonstrate experimentally that marine seasoned microplastics produce a dimethyl sulfide (DMS) signature that is also a keystone odorant for natural trophic interactions. We further demonstrate a positive relationship between DMS responsiveness and plastic ingestion frequency using procellariiform seabirds as a model taxonomic group. Together, these results suggest that plastic debris emits the scent of a marine infochemical, creating an olfactory trap for susceptible marine wildlife.

Matthew S. Savoca, Martha E. Wohlfeil, Susan E. Ebeler, Gabrielle A. Nevitt, Science Advances, 09 Nov 2016: Vol. 2, no. 11, e1600395

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Facilitated Leaching of Additive-Derived PBDEs from Plastic by Seabirds’ Stomach Oil and Accumulation in Tissues

Our previous study suggested the transfer of polybrominated diphenyl ether (PBDE) flame retardants from ingested plastics to seabirds’ tissues. To understand how the PBDEs are transferred, we studied leaching from plastics into digestive fluids. We hypothesized that stomach oil, which is present in the digestive tract of birds in the order Procellariiformes, acts as an organic solvent, facilitating the leaching of hydrophobic chemicals. Pieces of plastic compounded with deca-BDE were soaked in several leaching solutions. Trace amounts were leached into distilled water, seawater, and acidic pepsin solution. In contrast, over 20 times as much material was leached into stomach oil, and over 50 times as much into fish oil (a major component of stomach oil). Analysis of abdominal adipose, liver tissue, and ingested plastics from 18 wild seabirds collected from the North Pacific Ocean showed the occurrence of deca-BDE or hexa-BDEs in both the tissues and the ingested plastics in three of the birds, suggesting transfer from the plastic to the tissues. In birds with BDE209 in their tissues, the dominance of BDE207 over other nona-BDE isomers suggested biological debromination at the meta position. Model calculation of PBDE exposure to birds based on the results of the leaching experiments combined with field observations suggested the dominance of plastic-mediated internal exposure to BDE209 over exposure via prey.

Kosuke Tanaka, Hideshige Takada, Rei Yamashita, Kaoruko Mizukawa, Masa-aki Fukuwaka and Yutaka Watanuki, Environ. Sci. Technol.49 (19), pp 11799–11807, 2015

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