Below the surface: the impacts of COVID-19 on marine mammals

Photo credit: Bob Turner

By: Amber Dearden, Jennifer Chapman, Aroha Miller

Covid-19 appeared and spread across the globe in a matter of months. It affected many industries and aspects of daily life for us, but indirectly affected life under water too. The Ocean Watch team decided to take a closer look at three of these impacts on marine mammals that have arisen due to Covid-19.

1. Decreased marine vessel traffic
2. Impacts of plastic pollution
3. Changes in citizen science data collection

Human activities in the marine environment range from less intrusive, such as some recreational activities, to much more pervasive, such as large-scale commercial fisheries and cargo ships that travel thousands of kilometers across the seas. Our impacts are often more far reaching than we realize, for example disrupting the underwater soundscape, polluting the environment, or depleting stocks of important species. It only makes sense then, that if we remove these disturbances from the marine environment, we remove the threats they create. However, the effects are hard to determine when the scientists monitoring marine species are also unable to go out on the water. We depend on these observations to understand what is going on underwater.

The sound of silence – decreased marine vessel traffic
Because of COVID-19, fewer large ships have been sailing the seas, allowing the oceans to become quieter. Cetaceans (whales, porpoises, dolphins) use echolocation for communication, finding food, mates, and family. Less underwater noise due to fewer ships means that cetaceans are getting a respite from a normally noisy underwater soundscape.

Impacts of plastic pollution
Since the COVID-19 pandemic was declared, there has been a shift back to using disposable plastics such as single use plastic bags and personal protective equipment. However, once plastics enter the ocean, they break down into smaller and smaller pieces and can be mistaken for food. Marine mammals can also become entangled by plastics, such as discarded fishing lines and packing straps. This risk has been exacerbated by increased single use plastic use, and the reduced ability of the Marine Mammal Rescue Team to respond to calls because of strict COVID-19 health guidelines.

Changes in citizen science data collection
With boating activities, such as ferry sailings and ecotourism operators, being reduced or simply not operating, fewer people have been out on the water. AS a result, fewer cetacean sightings have been reported from the sea (but more from land), which implies whale sightings may have been missed. Cetacean sightings reported by citizens to the BC Cetacean Sightings Network (BCCSN) provide near real-time information to the WhaleReport Alert System (WRAS) on whale distribution.  The WRAS is then used to mitigate ship strikes on cetaceans by alerting ship pilots when they are near whales, allowing them to change course. Missed cetacean sighting results in a reduced ability to protect cetaceans from ship strikes.

These indirect impacts of the COVID-19 pandemic on marine mammals are just a selection. As we continue to observe the oceans, we will likely discover more. These unprecedented times have allowed us to take a step back and think more about what we can do to lessen our impacts on the natural world. For a more in-depth review of these impacts as well as a list of recommended actions you can take to lessen the impacts to marine mammals, view the full report.