This study examines whether a group of captive false killer whales(P seudorca crassidens) showed variations in the vocal rate around feeding times. The high level of motivation to express appetitive behaviors in capti...This study examines whether a group of captive false killer whales(P seudorca crassidens) showed variations in the vocal rate around feeding times. The high level of motivation to express appetitive behaviors in captive animals may lead them to respond with changes of the behavioral activities during the time prior to food deliveries which are referred to as food anticipatory activity. False killer whales at Qingdao Polar Ocean World(Qingdao, China) showed signifi cant variations of the rates of both the total sounds and sound classes(whistles, clicks, and burst pulses) around feedings. Precisely, from the Transition interval that recorded the lowest vocalization rate(3.40 s/m/d), the whales increased their acoustic emissions upon trainers' arrival(13.08 s/m/d). The high rate was maintained or intensifi ed throughout the food delivery(25.12 s/m/d), and then reduced immediately after the animals were fed(9.91 s/m/d). These changes in the false killer whales sound production rates around feeding times supports the hypothesis of the presence of a food anticipatory vocal activity. Although sound rates may not give detailed information regarding referential aspects of the animal communication it might still shed light about the arousal levels of the individuals during different social or environmental conditions. Further experiments should be performed to assess if variations of the time of feeding routines may affect the vocal activity of cetaceans in captivity as well as their welfare.展开更多
Nature reserves in the Yangtze River,China,are crucial for protecting the Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)and their habitats.Despite a 10-year fishing ban along the middle and lowe...Nature reserves in the Yangtze River,China,are crucial for protecting the Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)and their habitats.Despite a 10-year fishing ban along the middle and lower reaches of the Yangtze River instated on January 2020 to alleviate pressures on the porpoise's prey,other stressors,particularly underwater noise,continue to impact these rare cetaceans,which rely heavily on vocalization for prey detection,communication and navigation.Between September 2020 and September 2021,underwater noise monitoring was carried out in the Xinluo Baiji National Nature Reserve,located in Hubei province,China,with the aim of assessing the potential impact of underwater noise pollution on the Yangtze finless porpoise.The reserve was divided into 30 sub-sections to systematically monitor underwater noise across the reserve.Passive acoustic monitoring was conducted at each site within these sub-sections during four sampling periods,and these data were subjected to comparative analysis with data collected in 2012 and 2017.The results showed that the root mean square sound pressure levels at each site ranged from 117 to 162 dB.Power spectral levels(11.2–152 kHz)exceeded the average audiogram levels for the porpoise at most sites.94.2%and 93.3%of the sites exceeded underwater acoustic thresholds known to induce a hearing threshold shift for the porpoise in terms of both the averaged cumulative unweighted sound exposure level,and cumulative weighted sound exposure level respectively.Noise levels in this section during 2020–2021 were approximately 25 and 30 dB higher compared to the levels recorded in 2012 and 2017,and likely due to increased shipping activity and the proximity of sampling sites to the shipping channel.The rise in noise levels might contribute to the observed declines in the porpoise population within this area.To mitigate these impacts,implementing noise control measures is essential,such as regulating navigation speed and limiting the number of vessels in the reserve.展开更多
基金Supported by grants from the Institute of Hydrobiology,Chinese Academy of Sciences
文摘This study examines whether a group of captive false killer whales(P seudorca crassidens) showed variations in the vocal rate around feeding times. The high level of motivation to express appetitive behaviors in captive animals may lead them to respond with changes of the behavioral activities during the time prior to food deliveries which are referred to as food anticipatory activity. False killer whales at Qingdao Polar Ocean World(Qingdao, China) showed signifi cant variations of the rates of both the total sounds and sound classes(whistles, clicks, and burst pulses) around feedings. Precisely, from the Transition interval that recorded the lowest vocalization rate(3.40 s/m/d), the whales increased their acoustic emissions upon trainers' arrival(13.08 s/m/d). The high rate was maintained or intensifi ed throughout the food delivery(25.12 s/m/d), and then reduced immediately after the animals were fed(9.91 s/m/d). These changes in the false killer whales sound production rates around feeding times supports the hypothesis of the presence of a food anticipatory vocal activity. Although sound rates may not give detailed information regarding referential aspects of the animal communication it might still shed light about the arousal levels of the individuals during different social or environmental conditions. Further experiments should be performed to assess if variations of the time of feeding routines may affect the vocal activity of cetaceans in captivity as well as their welfare.
文摘Nature reserves in the Yangtze River,China,are crucial for protecting the Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis)and their habitats.Despite a 10-year fishing ban along the middle and lower reaches of the Yangtze River instated on January 2020 to alleviate pressures on the porpoise's prey,other stressors,particularly underwater noise,continue to impact these rare cetaceans,which rely heavily on vocalization for prey detection,communication and navigation.Between September 2020 and September 2021,underwater noise monitoring was carried out in the Xinluo Baiji National Nature Reserve,located in Hubei province,China,with the aim of assessing the potential impact of underwater noise pollution on the Yangtze finless porpoise.The reserve was divided into 30 sub-sections to systematically monitor underwater noise across the reserve.Passive acoustic monitoring was conducted at each site within these sub-sections during four sampling periods,and these data were subjected to comparative analysis with data collected in 2012 and 2017.The results showed that the root mean square sound pressure levels at each site ranged from 117 to 162 dB.Power spectral levels(11.2–152 kHz)exceeded the average audiogram levels for the porpoise at most sites.94.2%and 93.3%of the sites exceeded underwater acoustic thresholds known to induce a hearing threshold shift for the porpoise in terms of both the averaged cumulative unweighted sound exposure level,and cumulative weighted sound exposure level respectively.Noise levels in this section during 2020–2021 were approximately 25 and 30 dB higher compared to the levels recorded in 2012 and 2017,and likely due to increased shipping activity and the proximity of sampling sites to the shipping channel.The rise in noise levels might contribute to the observed declines in the porpoise population within this area.To mitigate these impacts,implementing noise control measures is essential,such as regulating navigation speed and limiting the number of vessels in the reserve.
