Impacts of Marine Plastic Pollution From Continental Coasts to Subtropical Gyres—Fish, Seabirds, and Other Vertebrates in the SE Pacific

Matías Portflitt-Toro,Guillermo Luna-Jorquera,Diego Miranda-Urbina,Martin Thiel,Carlos Zavalaga,Nicolas Ory,Iván A Hinojosa,Naiti Morales,Nicolás Luna,Rocío Álvarez-Varas,Aldo S Pacheco,Camila Gallardo

doi:10.3389/fmars.2018.00238

Abstract

Anthropogenic Marine Debris (AMD) in the SE Pacific has primarily local origins from land-based sources, including cities (coastal and inland), beach-goers, aquaculture, and fisheries. The low frequency of AMD colonized by oceanic biota (bryozoans, lepadid barnacles) suggests that most litter items from coastal waters of the Humboldt Current System (HCS) are pulled offshore into the South Pacific Subtropical Gyre (SPSG). The highest densities of floating micro- and macroplastics are reported from the SPSG. An extensive survey of photographic records, unpublished data, conference proceedings, and published studies revealed interactions with plastics for 97 species in the SE Pacific, including 20 species of fish, 5 sea turtles, 53 seabirds, and 19 marine mammals. Sea turtles are most affected by interactions with plastics, underlined by the fact that 4 of the 5 species suffer both from entanglement and ingestion. Reports gathered in this review suggest that interactions along the continental coast are mostly via entanglement. High frequencies of microplastic ingestion have been reported from planktivorous fish and seabirds inhabiting the oceanic waters and islands exposed to high densities of microplastics concentrated by oceanic currents in the SPSG. Our review also suggests that some species from the highly productive HCS face the risk of negative interactions with AMD, because food and plastic litter are concentrated in coastal front systems. In order to improve the conservation of marine vertebrates, especially of sea turtles, urgent measures of plastic reduction are needed.

Highlights

Marine plastic pollution is generating impacts on marine biota and ecosystems at many different levels (Ryan, 2016)
Our study showed that some species foraging in the highly productive Humboldt Current System (HCS) frequently interact with marine plastics, which at first glance might be surprising given that litter densities are substantially lower than in the open ocean
Interactions with marine plastic litter were documented for a total of 97 species of marine vertebrates

Summary

INTRODUCTION

Marine plastic pollution is generating impacts on marine biota and ecosystems at many different levels (Ryan, 2016). A large number of marine vertebrate species from the SE Pacific were documented to have interacted with marine litter, including fishes, seabirds, sea turtles, and marine mammals (Thiel et al, 2011; Miranda-Urbina et al, 2015; Ory et al, 2017). More species with plastic ingestion were documented along the continental coast than in the open ocean, and few oceanic species become entangled near oceanic islands (Rapa Nui and Salas and Gómez Island) It needs to be taken into account that the simple species list presented in Table 1 only shows whether a species had ingested microplastics or not, which does not allow for inferences on the individual risk of ingestion. On Rapa Nui, up to 10% of stranded AMD can have bitemarks (MT, unpublished data)

DISCUSSION

Findings

CONCLUSIONS AND OUTLOOK

ETHICS STATEMENT