Ghost Fishing
Picking up from where we left off, let’s dive deeper into the sources of marine plastic pollution. Specifically, we’ll look into the fishing industry.
Increasingly, plastics have been incorporated into fishing gear since they offer many benefits, including being light, durable, and low in cost. However, given that fishing gears are designed to capture marine animals, derelict fishing gears thus result in harmful impacts on the marine ecosystem. Coupled with the physical properties that make plastics good for fishing gears, this means that derelict fishing gear will remain in the oceans for a very long time, escalating the impacts on the marine ecosystem.
According to the WWF, 10% of plastic debris in the oceans comes from derelict fishing gear, with “between 500,000 to 1 million tons of fishing gear” being discarded or lost in the ocean annually (Nicolas, 2020, p. 2). Relative to other sources of marine plastic pollution, fishing nets are significantly less in terms of mass but has far more complex implications, whether on the marine ecosystem or even socio-economic impacts on humans (Kuczenski et al., 2021).
Amongst fishing gear left in the ocean, gillnets are the most common and are also the largest perpetrator for “ghost fishing” (Thomas et al., 2019); ghost fishing occurs as derelict fishing gear continue to capture marine animals in the oceans for an extended amount of time—even though no one is actually fishing—since plastics in the fishing gear makes them non-biodegradable.
Figure 1: Seal using derelict fishing nets as a pillow (NOAA, 2019)
As fishing nets, including gillnets, are non-selective, it also leads to bycatch. Ergo, not only the original target species of the fishing nets are caught and entangled in the nets, but other marine animals like sea turtles and sharks can get caught in the nets as well. Since these nets are unmanned, it implies that captured marine animals are left to struggle against the fishing nets and slowly die due to exhaustion or even suffocation (Nicolas, 2020). Ghost fishing also poses as a form of competition for fishermen, resulting in the loss of otherwise commercially valuable fish stocks.
Additionally, derelict fishing gear which is mobile can result in the introduction of invasive species, toxins, and chemical pollutants into the marine ecosystem, as well as the distribution of microalgae, which can result in harmful algal blooms. (The Nature Conservancy, 2021).
References
Kuczenski, B., Vargas Poulsen, C., Gilman, E. L., Musyl, M., Geyer, R., & Wilson, J. (2022). Plastic gear loss estimates from remote observation of industrial fishing activity. Fish and Fisheries, 23(1), 22–33. https://doi.org/10.1111/faf.12596
Nicolas, A. (2020, October 20). Ghost fishing gear. World Wildlife Fund. https://www.worldwildlife.org/stories/ghost-fishing-gear
NOAA. (2019). Monk seal using marine debris from derelict fishing nets as pillow. [Photograph]. https://unsplash.com/photos/zjfHfXykgDc
The Nature Conservancy. (2021, September 16). NEW RESEARCH: Fishing Gear Accounts for an Alarming Amount of Plastic Pollution in Oceans. The Nature Conservancy. https://bit.ly/3r5uTa6
Thomas, K., Dorey, C., & Obaidullah, F. (2019). Ghost Gear: The Abandoned Fishing Nets Haunting Our Oceans (pp. 1–20). Greenpeace Germany. https://www.greenpeace.org/static/planet4-aotearoa-stateless/2019/11/b97726c9-ghost_fishing_gear_report_en_single-page_051119.pdf