A study commissioned by the Cape of Good Hope SPCA on the impacts of fireworks on marine species has recommended the cessation of firework displays at the V&A Waterfront, citing the impacts of anthropogenic noise on wild animals.
They found Hartlaub’s gulls and Cape fur seals exhibited a “strong behavioural response during the firework display by increasing vocal behaviour, and the seals shifted from sleeping to vigilant and locomotive behaviour at the onset of the fireworks. In air, the frequency range of firework noise overlapped the vocal signals of both species, resulting in potential acoustic masking”.
The case study on the short-term impacts of fireworks on marine species comes after the dismissal of the SPCA’s high court application to interdict a New Year’s fireworks display from taking place at V&A Waterfront at midnight on December 31, 2023.
Authors Rachel Probert, Simon Elwen and Tess Gridley from Sea Search Research and Conservation aimed to assess the acute impacts on the behaviour of select marine species and assess the received sound pressure levels of the fireworks underwater.
The authors explain that while anthropogenic noise is prominent in the soundscape of many terrestrial and marine environments where wild animals may adapt to show tolerance or habituation, “sudden impulsive noise can trigger behavioural responses”.
Video and acoustic data were collected from December 31, 2023 to January 1, 2024, to assess the vocal and behavioural changes of Hartlaub’s gulls and Cape fur seals.
“The animals inhabiting the Waterfront are relatively habituated to human presence and anthropogenic disturbance associated with the V&A Waterfront, for example boat noise and live music.
“Despite habituation, the two species included in this study showed strong behavioural responses to the firework display. Both species considerably increased their vocal production rate during this period, previously described as an increased stress response in other species.
“A total of 2 754 Cape fur seal vocalisations and 1 101 Hartlaub’s gull caws were documented from 3pm on December 31, 2023 to 9am on January 1, 2024. The frequency range of the loudest fireworks (50Hz – 4kHz) overlapped with the frequency range of Hartlaub’s gull caws (1.5 – 3kHz fundamental frequency) and Cape fur seal vocalisations (100Hz – 3kHz fundamental frequency and loudest harmonics) indicating the sound of fireworks is emitted at a biologically important bandwidth and may result in potential masking of vocalisations,” the authors found.
They ultimately recommended the cessation of firework displays at the V&A Waterfront, adding “most of the species inhabiting the V&A waterfront are protected species, and results indicate that behavioural responses likely indicate harassment as defined by various protection acts”.
“Human activity that triggers behavioural alterations of wild animals, which can result in increased energy use or injury, is defined as harassment. This includes anthropogenic noise disturbance when there are indications that an animal has heard a sound or when their behaviour is altered, which is regarded as harassment from a legal perspective.
“Although not of a high conservation concern, both Hartlaub’s gulls and Cape fur seals, along with many others found at the V&A waterfront (Cape cormorant, African penguin, swift tern, African oystercatcher, kelp gull, Cape clawless otter, and dolphin and whale species) are protected or vulnerable species as per the National Environmental Management Biodiversity Act 10 of 2004 which prohibits the harassment of all listed species.”
The V&A Waterfront did not respond to requests for comment by deadline on Tuesday.
Cape Times