Modeling Plastics Exposure for the Marine Biota: Risk Maps for Fin Whales in the Pelagos Sanctuary (North-Western Mediterranean)

Abstract

Several anthropogenic stressors threaten the Mediterranean basin, which is currently regarded as one of the most impacted marine ecoregions globally. Among those stressors, marine plastic litter is causing increasing concern about its environmental and biological consequences, the latter being largely unknown. To improve the understanding of these aspects, here we provide a mapped indicator of the risk of plastic ingestion by the fin whale Balaenoptera physalus, an endangered cetacean whose feeding grounds are located within the Pelagos Sanctuary for Mediterranean Marine Mammals, in the northwestern Mediterranean Sea. We analyse a decade (2000-2010) of advection patterns of marine plastic litter, modeled as Lagrangian particles and released from the three major sources: untreated waste along coasts, plastic discharged from rivers and along maritime shipping routes. Risk of exposure to microplastics via food ingestion for fin whales is then evaluated by interlacing the plastic litter distribution obtained via particle tracking with maps of habitat suitability based on bathymetry and satellite-derived estimates of chlorophyll-a. Our modeling results locate the highest risk values in the Central Ligurian Sea, and show that all the three main sources of plastic litter taken into account clearly contribute to impacting cetaceans in the Sanctuary, yet with spatial and interannual variability of patterns. The procedure formalized with our approach can be extended to assess the risk caused by ingestion of plastics by other taxa and/or in other MPAs, as we suggest by providing an application on the whole ecosystem of Pelagos, thus informing targeted actions to tackle the complex issue of marine litter.

Assessing meso- and microplastic pollution in the Ligurian and Tyrrhenian Seas

“…as a 'plastic soup' in the literature (Suaria et al, 2016). This high heterogeneity leads some researchers, such as Guerrini et al (2019), to argue that environmental sampling campaigns within the region provide only a temporally specific snapshot of the state of the Mediterranean (Guerrini et al, 2019). Thus, differences in the concentrations obtained at different times, particularly if the samples are collected years apart, are likely to be the result of the region's heterogenous pollution distribution.…”

“…Within the region sampled during this study, the Magra, Serchio, Arno, Ombrone, Tevere, Tavignano, Golo, Tirso, and Flumendosa rivers flow directly into the sea. Additionally, the study by Guerrini et al points out the importance of accounting for the potential impact of multiple major marine shipping routes, such as those running from Genoa or Livorno to Barcelona (Guerrini et al, 2019). However, as only buoyant materials were collected during this study, it is very important to consider the overall influence of ocean currents on the movement of the particles.…”

Turtles on the trash track: loggerhead turtles exposed to floating plastic in the Mediterranean Sea

“…The harm caused by marine litter to wildlife is determined by the combination of the likelihood of colliding with, ingesting, or becoming entangled in plastic items, and the consequences of these interactions (Darmon et al 2016, Guerrini et al 2019. Gastro-intestinal obstruction, internal injuries, a false sense of satiation with decreased absorption of nutrients, and disruption of the endocrine system due to the consumption of leached toxic substances are amongst the most commonly reported consequences of plastic ingestion.…”

Earth Observations for Monitoring Marine Coastal Hazards and Their Drivers

“…From Greidanus et al (2017) floats close to the ocean surface. Most of plastic is fragmented into micro or nanoplastics through the action of solar radiation and marine conditions (wind, currents), sink in the ocean, is ingested by fishes or marine mammals, which represent a hazard for their health (e.g., Guerrini et al 2019) or ends up on beaches (van Sebille et al 2020).…”