Managing the footprint of highly mobile fishing fleets is increasingly important due to continuing declines in fish populations. However, social‐ecological drivers for fisher behaviour remain poorly understood for many fleets globally. Using the Sri Lankan fleet as a case study, we explored the role of social, environmental and policy drivers of effort distribution and illegal fishing. We used semi‐structured interviews and participatory mapping with 95 fishers, combined with explanatory modelling (GLM) and multivariate statistics, including principal component analysis (PCA). Our findings highlighted the broad footprint (~3,800,000 km²) of this fleet, with fishing effort expended in high seas (53.9%), domestic (40.9%) and, illegally, in foreign waters (5.2%). Twenty‐six per cent of fishers directly admitted to fishing illegally in foreign waters during interviews, whereas 62% of fishers indicated doing so during participatory mapping. GLMs explained underlying decisions of where to fish (36% of the total deviance in effort distribution) as a function of social variables (14%), notably distance from landing sites (13%), and environmental variables (11%), notably sea surface temperature (10%). Multivariate analysis revealed that individual fisher characteristics associated with illegal fishing, such as a level of reliance on sharks, vary across the fleet. The analysis of qualitative data suggested that the influence of interpersonal and community social networks and perceptions of higher catch value, particularly of sharks, may be important. Our approach demonstrated the utility of mixed methods research, including the collection of qualitative data, for creating a detailed understanding of spatial behaviour, including decisions of whether to fish illegally. Results highlighted the importance of adopting a social‐ecological lens to investigate drivers for human behaviour and non‐compliance with rules. We advocate for a nuanced approach to monitoring and managing of fleets, including investigating localised social drivers for illegal fishing and enhancing regional transparency in fleet monitoring. A free Plain Language Summary can be found within the Supporting Information of this article.

The accumulation of Mismanaged Plastic Waste (MPW) in the environment is a global concern. The amount of waste generated by countries is estimated using globally available data layers and/or empirical surveys. Unlike globally available metadata, MPW estimates based on empirical surveys allow for better visualization of amounts, potential pathways, and hotspots. A model study conducted in 2015, based on global metadata, ranked Sri Lanka in fifth position among the world’s worst mismanaged plastic offenders. However, there is significant uncertainty in the source data on waste generation and the parameters used for model prediction, such as plastic usage (5.1 kg per person per day), since Sri Lanka is predominantly a service-based country with limited plastic-based manufacturing industries. The source data for plastic usage has been derived from a very limited study, biased toward waste hotspots that have not been verified. Our empirical data has shown that population density, one of the key parameters used for global ranking, is a weak predictor of debris densities. Therefore, we argue that the given plastic leakage data and the ranking is an error. Therefore, Sri Lanka’s position in the global ranking deserves reconsideration. Further, we propose the need for model predictions that rely on global metadata to be backed by robust and unbiased designed surveys that are based on empirical data and undergo intense baseline data verification to generate more precise predictions on litter quantities.

This study evaluated the degradability of three products, namely an oxo-degradable garbage bag (GB), compostable lunch sheet (LS), and biodegradable salad plate (SP), under four controlled laboratory simulations representing natural environmental conditions: freshwater body (FW), riverbank (RS), landfill (COM), and direct ultraviolet (UV) light exposure. Degradation was assessed over time by monitoring the monthly changes in weight. Mechanical and chemical changes were monitored using tensile strength testing and Fourier-transform infrared (FT-IR) spectroscopy, respectively. Among the tested products, SP exhibited the highest mean percentage weight loss (43.76±3.34 to 100%) under RS conditions. Instead of weakening, GB exhibited increased mean tensile strength at break and mean elongation at break under RS (7.25±0.29 and 317.78±9.15, respectively) and COM (4.35±0.88 and 46.16±28.11, respectively), suggesting possible crosslinking or physical aging rather than degradation. No loss of characteristic peaks indicating biodegradation of the polymer material was observed in SP under FW and UV exposure, LS under UV exposure, and GB under FW, RS, or COM exposure. The findings highlight that degradation rates vary substantially across different environmental media and sample types. The potential contribution of certain biodegradable materials, particularly oxo low-density polyethylene (oxo-LDPE), to long-term plastic pollution is emphasized in this study.