Towards understanding the effects of oceanic plastic pollution on population growth for a South American fur seal (Arctocephalus australis australis) colony in Chile

Using long-term citizen science data to distinguish zones of debris accumulation

Studies show that a driver of coastal debris is the rate between debris deposition and resuspension; however, the influence of beach zone topography on the distribution of debris remains poorly understood. Using five years of marine debris data collected by the COASST citizen science program, we explored the spatiotemporal trends in debris abundance within two regions of the United States Pacific Northwest and investigated whether higher debris loads are associated with beach zones that have a higher propensity to trap debris. We found that beaches with larger wood zones had higher debris loads, adding to the growing evidence that backshore areas of beaches act as sinks for debris. Higher debris loads were also associated with beaches that had larger wrack zones suggesting that onshore transport from the marine reservoir is a dominant source of debris. This study provides a long-term baseline of marine debris which managers could use to inform source reduction interventions.

Can we quantify the aquatic environmental plastic load from aquaculture?

Aquaculture provides livelihoods for hundreds of millions of people, but it also forms a significant source of plastic litter that poses a serious hazard to aquatic ecosystems. How to assess and subsequently manage plastic loads from aquaculture is a pending and pressing issue for aquaculture sustainability, and an important concern for water environment monitoring and management. In this study, we developed the first framework for estimating plastic litter from aquaculture by combining data from satellite remote sensing, drones, questionnaires, and in situ measurements. By acquiring multidimensional (human and nature) and multiscale (centimeter to basin scale) data, this framework helped us understand the aquaculture farming patterns and its spatial and temporal evolution, and thus estimate the plastic load it generates and suggest effective management approaches. Applying this framework, we assessed the marine plastic load from oyster floating raft farming in the Maowei Sea, a typical mariculture bay in China, with an increasing farming area. Approximately 3840 tons of plastic waste is expected to be discharged into the sea in the next four years (the average service life of a floating raft) without improvements in aquaculture waste management. Strengthening governance, timely plastic removal, innovative replacement, and transforming farmers' behavior patterns are recommended as the subsequent measures for plastic management. This framework can be extended to other regions and other aquaculture patterns, and is applicable to local, regional, and global aquaculture plastic litter assessments. It is a source-based method for evaluating plastic pollution that is more conducive to subsequent plastic management than traditional post-contamination environmental monitoring. In the context of the global expansion of mariculture and the global commitment to action to combat plastic pollution, this approach could play a critical role in the investigation and management of plastic waste in aquatic environments.

Impact of marine debris recorded in a sympatric colony of otariids in the south coast of Peru

Marine debris, in particular plastic debris and debris related to fishing activities, have an impact on marine mammals and seabirds. In marine-coastal species such as otariids, we can detect the incidence of these interactions through land-based observations. In this study, we recorded and described interactions between marine debris and the otariids Arctocephalus australis and Otaria byronia in a natural protected area in Peru, according to age class categories. Between 2016 and 2020, we recorded 151 animals that were directly impacted and/or were observed interacting with marine debris. Residual collars from fishing gear, ropes, plastic bags and unidentified material were recorded. Direct interactions with debris at colonies (e.g., plastic bags) were also recorded, as well as animals evidenced interacting with hooks. The age class category and species with the highest number of individuals impacted by residual collars were adult female A. australis and subadult male O. byronia. Single-use plastics were the most commonly bitten/moved waste by animals in the reserve. In the case of hooks, these were mostly lodged in the mouths of otariids. Our results highlight the importance of continuing to promote segregation at source, as well as the correct disposal of waste, locally and globally, to mitigate impacts on marine fauna.

The Management of Agriculture Plastic Waste in the Framework of Circular Economy. Case of the Almeria Greenhouse (Spain)

In recent decades, ecosystems have suffered diverse environmental impacts caused by anthropogenic activities, including the dumping of plastic waste. This situation has prompted the European Union to introduce a new policy based on the circular economy. In this study, the present state and future perspectives on the generation and treatment of plastic waste in the intensive agriculture of Almeria (Spain) are analyzed. This activity generates 1503.6 kg·ha⁻¹·year⁻¹, on average, of plastic waste with an approximate treatment cost of 0.25 €/kg. The present study shows that the volume of plastic waste from intensive agriculture in Almeria is constantly increasing (48,948.2 tons in 2020/21) and it is suggested that the current management system does not meet the needs of the sector. Although it presents great opportunities for improvement under the framework of the circular economy. Furthermore, this work reports a direct relationship between the price of the raw materials needed for the production of plastic and the volume of recycled plastics. For this reason, it would be advisable for the administration to consider the implementation of a tax rebate system for the sector and specifically when the petroleum derivatives used to manufacture plastic are less expensive, and the recycling option is not so attractive.

Entanglement of Cape fur seals (Arctocephalus pusillus pusillus) at colonies in central Namibia

Marine pollution is increasing, and pinnipeds are commonly affected by entanglement in waste. We investigated entanglement rates, common materials, and the demographic profile of Cape fur seals (Arctocephalus pusillus pusillus) affected at two Namibian colonies. Overall, we identified 366 cases of entanglement, and present a global rate of entanglement of 0.17%. Entanglement rates were 0.17% and 0.15% for the Pelican Point and Cape Cross colonies, respectively. We identified 17% more entanglements through photographs than binocular scans. Of the 347 entanglements analysed in detail, juveniles were most commonly affected and fishing materials were the primary cause of entanglements (53%), with 8% of entangled seals exhibiting 'very severe' injuries. Overall, 191 individuals were successfully disentangled, and citizen scientists contributed 51% of total entanglement data. We highlight the negative impact of plastic marine waste among seals and the importance of disentanglement for individual animal welfare.