Diversity of fish sound types in the Pearl River Estuary, China

Abstract

Background. Repetitive species-specific sound enables the identification of the presence and behavior of soniferous species by acoustic means. Passive acoustic monitoring has been widely applied to monitor the spatial and temporal occurrence and behavior of calling species. Methods. Underwater biological sounds in the Pearl River Estuary, China, were collected using passive acoustic monitoring, with special attention paid to fish sounds. A total of 1408 suspected fish calls comprising 18,942 pulses were qualitatively analyzed using a customized acoustic analysis routine. Results. We identified a diversity of 66 types of fish sounds. In addition to single pulse, the sounds tended to have a pulse train structure. The pulses were characterized by an approximate 8 ms duration, with a peak frequency from 500 to 2600 Hz and a majority of the energy below 4000 Hz. The median inter-pulsepeak interval (IPPI) of most call types was 9 or 10 ms. Most call types with median IPPIs of 9 ms and 10 ms were observed at times that were exclusive from each other, suggesting that they might be produced by different species. According to the literature, the two section signal types of 1+1 and 1+N 10 might belong to big-snout croaker (Johnius macrorhynus), and 1+N 19 might be produced by Belanger's croaker (J. belangerii).Discussion. Categorization of the baseline ambient biological sound is an important first step in mapping the spatial and temporal patterns of soniferous fishes. The next step is the identification of the species producing each sound. The distribution pattern of soniferous fishes will be helpful for the protection and management of local fishery resources and in marine environmental impact assessment. Since the local vulnerable Indo-Pacific humpback dolphin (Sousa chinensis) mainly preys on soniferous fishes, the fine-scale distribution pattern of soniferous fishes can aid in the conservation of this species.Additionally, prey and predator relationships can be observed when a database of species- AbstractBackground. Repetitive species-specific sound enables the identification of the presence and behavior of

Distribution and habitat characteristics of three sympatric cetacean species in the coastal waters of Matang, Perak, Peninsular Malaysia

“…Humpback dolphins in Matang estuaries frequently consumed the body of the Sagor catfish, but avoided ingesting the head of the catfish, which has thick and sharp dorsal and pectoral spines (Kuit et al, ). It has been hypothesized that humpback dolphins in the Pearl River Estuary used passive listening when foraging and to explore the acoustic cues of their soniferous prey species in the estuaries (Barros et al, ; Pine, Wang, Porter, & Wang, ; Wang et al, ). Ariids and croakers are soniferous fishes that produce sound (Mazlan, Abdullah, Sharmina, & Arshad, ; Mok, Lin, & Tsai, ), and this suggests that passive listening for soniferous estuarine prey may provide an advantage for the foraging efficiency of humpback dolphins in the turbid waters of Matang.…”

Temporal variation of the underwater soundscape in Jiaotou Bay, an Indo‐Pacific humpback dolphin (Sousa chinensis) habitat off Hainan Island, China

“…In the Pearl River Estuary, 350 km northeast of Hainan Island, fish sounds were reported with a peak frequency of 0.5 to 2.6 kHz and with most energy below 4 kHz (Wang et al . 2017). Nearly all inter call intervals (ICIs) of fish sounds were over 5 ms, the median ICIs of most call types was 9 or 10 ms (Wang et al .…”

“…The minimum number of calls in a fish call train was conservatively set at 5, as most soniferous fish calls were almost always exhibiting as train of calls containing over 5 to up to several tens of calls (Wang et al . 2017). This criterion was widely used to identify click trains of finless porpoises (Akamatsu et al .…”

“…According to the results of Wang et al . (2017), the minimum ICI was set at 5 ms, and the maximum average ICI of a single fish call train was set at 30 ms. Fish call trains were identified as having almost constant ICIs and SPLs, with successive ICI and SPL greater than half and less than double the previous ones.…”

“…Fish sounds in shallow waters southwest of Hainan Island, China, were categorized into 6 types with the energy range from 0.1 to 2 kHz except 1 category with a wide frequency band (0.2-10 kHz) (Xu et al 2020). In the Pearl River Estuary, 350 km northeast of Hainan Island, fish sounds were reported with a peak frequency of 0.5 to 2.6 kHz and with most energy below 4 kHz (Wang et al 2017). Nearly all inter call intervals (ICIs) of fish sounds were over 5 ms, the median ICIs of most call types was 9 or 10 ms (Wang et al 2017).…”