Ingestion of anthropogenic litter has been well documented in marine vertebrates, but comparatively little is known about marine invertebrates. We report macrolitter ingestion by the sandy anemone ...Bunodactis reynaudi at Muizenberg beach in False Bay, South Africa. Monthly surveys from May 2015 to August 2019 collected 491 ingested litter items (9.4 ± 14.9 items·month-1, 39.8 ± 71.5 g·month-1), of which >99% were plastic. The number of ingested items was correlated with the abundance of stranded items and ingestion peaked in autumn when seasonal rains washed more litter into the bay. Most ingested litter was clear (39%), white (16%) and black/purple (15%). Comparison with environmental litter showed selection for flexible plastics, particularly bags/packets and food packaging. Experimental feeding trials found that B. reynaudi selected for pieces of HDPE bag suspended in seawater for 2–20 days, suggesting that biofilms enhance the palatability of flexible plastics. Studies are needed to assess the possible impacts of plastic ingestion on B. reynaudi. While only a small proportion of the population currently ingest litter, ingestion might become more common if environmental litter loads increase. This might negatively affect the anemone’s ability to respond to other environmental changes such as increasing levels of heavy metal pollution.
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•We report the first record of macroplastic ingestion by a sessile anemone.•Approximately 1% of Bunodactis reynaudi ingested litter items each month.•B. reynaudi preferred flexible plastics (bags/packets and food packaging).•The incidence of ingestion was linked to litter abundance in the environment.•Feeding trials suggest that biofilms enhance the palatability of HDPE bags.
Most monitoring studies of marine anthropogenic debris have focused on sandy beaches, so little is known about litter on rocky shorelines. We surveyed litter trapped on a rocky intertidal shore in ...False Bay, South Africa, between May 2015 and March 2018. An exceptional upwelling of seabed litter occurred in November 2017 (70 items∙m−1). Excluding this event, monthly clean-ups at spring low tide collected 2 (1.3–3.1) items∙m−1∙month−1 and 31 (19.4–49.4) g∙m−1∙month−1 of which 74% was plastic (31% by mass). Litter loads peaked in autumn when seasonal rains washed litter into False Bay, suggesting that most litter comes from local land-based sources. Litter composition differed from that on a nearby sandy beach, with more glass and other dense items on the rocky shore, but 60% of plastic items floated in water. Sand inundation and biotic interactions helped to trap buoyant plastics in the intertidal zone.
•One of few studies to monitor litter trapped on a rocky intertidal shore•Plastics made up 74% of litter by count but only 31% by mass.•Most plastic was disposable flexible packaging (bags and food packaging).•Litter loads 1–2 orders of magnitude higher than average during an upwelling event.•Rocky shore trapped more bags/packets, but less rigid plastics, than nearby sandy beach.
Over the past three decades, marine resource management has shifted conceptually from top-down sectoral approaches towards the more systems-oriented multi-stakeholder frameworks of integrated coastal ...management and ecosystem-based conservation. However, the successful implementation of such frameworks is commonly hindered by a lack of cross-disciplinary knowledge transfer, especially between natural and social sciences. This review represents a holistic synthesis of three decades of change in the oceanography, biology and human dimension of False Bay, South Africa. The productivity of marine life in this bay and its close vicinity to the steadily growing metropolis of Cape Town have led to its socio-economic significance throughout history. Considerable research has highlighted shifts driven by climate change, human population growth, serial overfishing, and coastal development. Upwelling-inducing winds have increased in the region, leading to cooling and likely to nutrient enrichment of the bay. Subsequently the distributions of key components of the marine ecosystem have shifted eastward, including kelp, rock lobsters, seabirds, pelagic fish, and several alien invasive species. Increasing sea level and exposure to storm surges contribute to coastal erosion of the sandy shorelines in the bay, causing losses in coastal infrastructure and posing risk to coastal developments. Since the 1980s, the human population of Cape Town has doubled, and with it pollution has amplified. Overfishing has led to drastic declines in the catches of numerous commercially and recreationally targeted fish, and illegal fishing is widespread. The tourism value of the bay contributes substantially to the country’s economy, and whale watching, shark-cage diving and water sports have become important sources of revenue. Compliance with fisheries and environmental regulations would benefit from a systems-oriented approach whereby coastal systems are managed holistically, embracing both social and ecological goals. In this context, we synthesize knowledge and provide recommendations for multidisciplinary research and monitoring to achieve a better balance between developmental and environmental agendas.
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