Noise field characterization in the habitat of the East Taiwan Strait Indo-Pacific Humpback Dolphin during the pile driving activity of demonstration offshore wind farm

Abstract

The Eastern Taiwan Strait (ETS) population of Indo-Pacific humpback dolphin (Sousa chinensis) is listed critically endangered in the Red List of Threatened Species by the International Union for Conservation of Nature due to its small population size and narrow distribution. The humpback dolphin habitats off the coast of Miaoli and Changhua are sites selected for future wind farms, therefore, the noise impact of pile driving on this critically endangered population is expected to be serious. This paper presents works done in (1) characterizing the sound field during the test pile driving and associated activities in the humpback dolphin habitat; (2) identifying dominant anthropogenic noise sources of the dolphin habitat during the construction of demonstration wind turbines and associated activities; and (3) examining the implications of the sound field from wind turbine construction and associated activities in relation to humpback dolphins’ hearing and communication. The results from the study can provide critical information and conservation recommendations for an environmental impact analysis for the full scale wind farm construction in 2017.

Habitat protection actions for the Indo‐Pacific humpback dolphin: Baseline gaps, scopes, and resolutions for the Taiwanese subspecies

“…These LCH waters should be protected immediately under the strictest disciplines. Activities inside the LHM that permanently alter the oceanographic and ecological features, such as a continuing wind farm project (Chen, Guan, et al, ), should be critically re‐evaluated and revised accordingly.…”

“…The Indo‐Pacific humpback dolphin, Sousa chinensis , generally inhabits inshore (<20 m deep) waters in coastal and estuarine environments (Chen, Xu, et al, ; Jefferson, ; Jefferson & Hung, ; Jefferson & Karczmarski, ; Jutapruet et al, ; Jutapruet, Intongcome, Wang, Kittiwattanawong, & Huang, ; Wu, Jefferson, et al, ). Many humpback dolphin habitats are currently threatened by anthropogenic activities associated with coastal alterations (land reclamation, embankment, harbour construction, and aquaculture) (Chen, Huang, & Han, ; Jutapruet et al, ; Karczmarski et al, ; MacKinnon, Verkuil, & Murray, ; Wang, Wu, et al, ; Wu, Xu, et al, ), unregulated fishery activities (Jefferson & Smith, ; Slooten et al, ), pollutant accumulation (Gui et al, , ; Hung et al, ; Parsons, ), and underwater noises (Chen, Guan, et al, ; Pine, Wang, & Wang, ). Among these factors, recent studies have revealed that coastal alterations that immediately change the coastline geometry and substrate have altered the distribution of the humpback dolphin (Karczmarski et al, ; Wang, Wu, et al, ; Wu, Xu, et al, ).…”

Impact of pile‐driving and offshore windfarm operational noise on fish chorusing

“…1). These two turbines were the part of the Formosa 1 offshore windfarm project (Chen et al, 2017;Tseng, Lee, & Liao, 2017). Turbines were installed at a depth of ~35-55 m on a sandy substrate.…”

“…Turbines were installed at a depth of ~35-55 m on a sandy substrate. The two monopiles were 5.8 m in diameter and ~70 m in height (Chen et al, 2017). Geographical coordinates, pile driving start/end time, duration, and number of strikes are shown in Table 1.…”

“…The noise and vibrations generated by offshore wind turbines during the construction and operation phase have recently been found to negatively impact hearing sensitivity and cause behavioral changes in numerous marine organisms even at ranges of many kilometers distance from the windfarm (Nedwell, Langworthy, & Howell, 2003;Thomsen et al, 2006;Vella et al, 2001). During the construction of offshore windfarms, the most conspicuous sources of noise and vibrations are piling and dredging (Nedwell et al, 2007), which produce sound pressure level peaking at up to 187 dB re 1 lPa (Chen et al, 2017). Shipping in the area also contributes to increasing noise levels as the ª 2021 The Authors.…”