Multiple anthropogenic stressors in the Galápagos Islands' complex social–ecological system: Interactions of marine pollution, fishing pressure, and climate change with management recommendations

Abstract

For decades, multiple anthropogenic stressors have threatened the Galápagos Islands. Widespread marine pollution such as oil spills, persistent organic pollutants, metals, and ocean plastic pollution has been linked to concerning changes in the ecophysiology and health of Galápagos species. Simultaneously, illegal, unreported, and unregulated fishing are reshaping the composition and structure of endemic and native Galápagos pelagic communities. In this novel review, we discuss the impact of anthropogenic pollutants and their associated ecotoxicological implications for Galápagos species in the face of climate change stressors. We emphasize the importance of considering fishing pressure and marine pollution, in combination with climate-change impacts, when assessing the evolutionary fitness of species inhabiting the Galápagos. For example, the survival of endemic marine iguanas has been negatively affected by organic hydrocarbons introduced via oil spills, and endangered Galápagos sea lions exhibit detectable concentrations of DDT, triggering potential feminization effects and compromising the species' survival. During periods of ocean warming (El Niño events) when endemic species undergo nutritional stress, climate change may increase the vulnerability of these species to the impacts of pollutants, resulting in the species reaching its population tipping point. Marine plastics are emerging as a deleterious and widespread threat to endemic species. The Galápagos is treasured for its historical significance and its unparalleled living laboratory and display of evolutionary processes; however, this unique and iconic paradise will remain in jeopardy until multidisciplinary and comprehensive preventative management plans are put in place to mitigate and eliminate the effects of anthropogenic stressors facing the islands today. We present a critical analysis and synthesis of anthropogenic stressors with some progress from local and international institutional efforts and call to action more precautionary measures along with new management philosophies focused on understanding the processes of change through research to champion the conservation of the Galápagos.

Modelling microplastic bioaccumulation and biomagnification potential in the Galápagos penguin ecosystem using Ecopath and Ecosim (EwE) with Ecotracer

“…Lastly, numerous studies note prominent ingestion of microplastics when organisms are exposed to plastic particles in the environment or in laboratory conditions. Microplastic ingestion has been linked with several primarily sublethal health effects [ 31 , 34 , 110 , 111 ] and, therefore, it is plausible that ingested microplastics do not offer advantages in stressful changing oceanic conditions further harmed by overfished resources and climate change effects [ 112 ]. Instead, the presence of microplastics or nanoplastics may independently pose a significant concern and may be magnified by other environmental challenges [ 113 ].…”

Galápagos and the plastic problem

“…The labels on the analyzed Chinaorigin products were legible, lacking biofouling, and containing recent expiration dates, thus suggesting that they experienced little environmental degradation and were likely to have been in the water and on the beaches for a relatively brief period. It is likely that the poor waste management systems of industrial fishing fleets are responsible for the abundance of plastics with China origins on the islands (Donnelly et al, 2020;Moreno, 2021;Schofield et al, 2021;Alava et al, 2022;Leonhardt, 2022). It is important to note that the items found cannot be readily purchased in Galápagos or mainland Ecuador, further supporting the theory that they originated from the Chinese fishing fleet.…”

“…Despite its isolation, the islands are safeguarded; therefore, we may observe almost the same environment as Darwin observed nearly 200 years ago. Nonetheless, it is paradoxically vulnerable to stresses from humancaused global factors such as climate change and plastic pollution (Alava et al, 2022).…”

Ecotoxicological Assessment of Microplastics and Cellulose Particles in the Galápagos Islands and Galápagos Penguin Food Web

“…The Humboldt Current delivers cool waters and nutrients vital for iconic animals like the Galápagos penguin ( Spheniscus mendiculus ) and acts as a conduit of microplastic transportation from the mainland of South America and nearby fishing zones (Jones et al, 2021; Schofield et al, 2020; van Sebille et al, 2019). Tourism and, to a lesser extent, local activities also release microplastics (Alava et al, 2022; Jones et al, 2021). Suspected plastic particle concentrations ranged from 0.01 to 0.15 particles m –3 (with a minimum size of 150 µm) in international waters around the archipelago (Alfaro‐Núñez et al, 2021), and plastic particle concentrations of 0.04 to 0.89 particles m –3 were detected in various locations across marine‐coastal zones of San Cristóbal Island (Jones et al, 2021).…”