Plastic pollution is killing marine megafauna, but how do we prioritize policies to reduce mortality?

Abstract

Pollution by plastic and other debris is a problem affecting the world's oceans and is increasing through time. The problem is so large that prioritizing solutions to effect meaningful change may seem overwhelming to the public and policy makers. Marine megafauna are known to mistakenly eat anthropogenic debris and die from consequent gastrointestinal blockages, perforations and malnutrition, as well as suffer sublethal impacts. We collated information on which specific items were ingested and responsible for causing death across 80 marine species, including cetaceans, pinnipeds, sea turtles, and seabirds. We evaluated which items were responsible for the highest mortality, and which, if reduced by policy responses or other means, could result in the largest reduction in debris mortality. A limited number of consumer items were shown to be responsible for most megafauna deaths. Flexible plastic is responsible for the largest proportion of debris deaths, primarily due to gastric obstructions. Disproportionately lethal items included plastic bags/sheets/packaging, rope/fishing nets, fishing tackle and balloons/latex. Smaller items, including "microplastics," though abundant, were seldom implicated in mortality. We provide suggestions to directly curb debris deaths of marine megafauna by prioritizing policies that would reduce or eliminate the input of disproportionately hazardous items into the marine system.

Plastics in the Indian Ocean – sources, transport, distribution, and impacts

“…Even confirmed cases of individual deaths are not readily translated to impact on species or ecosystem levels. Recently, Roman et al (2021) determined which types of plastic debris contribute the most to mortality in marine megafauna (cetaceans, pinnipeds, sea turtles, and seabirds). In the IO plastic ingestion has been studied in sea turtles (Hoaru et al, 2014) and seabirds (Cherel et al, 2017;Cartraud et al, 2019).…”

“…For turtles, Roman et al (2021) concluded that film-like plastics, plastic fragments, and hard plastics were most likely to cause death. Although Hoarau et al (2014) did not find a relationship between the mortality of loggerhead turtles in the southwest IO and the type of plastic debris they had ingested, they did find a correlation between the length of debris and mortality.…”

Cetaceans Sightings During Research Cruises in Three Remote Atlantic British Overseas Territories

“…However, there are emerging threats, particularly from climate change impacts on food availability, e.g., krill, Euphausia superba, in the Southern Ocean (Atkinson et al, 2019;Morley et al, 2020). Pollution, such as plastics, are increasing globally (see Barnes et al, 2018 for the Atlantic) and negative impacts of macroplastics on cetaceans are regularly reported (Roman et al, 2020). To monitor the impacts of these emerging threats, any information that will improve the knowledge of locations used by cetaceans as their populations recover and start to spread back into previous grounds, will aid zonal planning and ecosystem based management of fisheries (e.g., Requena et al, 2020).…”

Evaluation of the environmental perception of the users over solid residues on the beach of Tamandaré/Brazil

“…The presence of marine residues, mostly resulting from anthropic activities, is responsible for the degradation of the coastal and marine ecosystem (Barbosa et al, 2018;Garcés-Ordóñez et al, 2020). This issue has led to serious environmental and socioeconomic problems, ranging from water contamination (Maynard et al, 2021), death of marine animals by ingestion or entanglement (Roman et al, 2020), expenditures on cleanup and the loss of tourism potential (Krelling et al, 2017). Studies have revealed that plastic is the most expressive item in coastal areas in Brazil (Araújo, 2003;Magalhães & Araújo, 2012;Sassaki et al, 2016;Santos, 2017;Nobre et al, 2018;Andrades et al, 2020;Gonçalves, 2020;Ribeiro et al, 2021).…”