title: Indo-Pacific humpback dolphin occurrence north of Lantau Island, Hong Kong, based on year-round passive acoustic monitoring.
abstract: Long-term passive acoustic monitoring (PAM) was conducted to study Indo-Pacific humpback dolphins, Sousa chinensis, as part of environmental impact assessments for several major coastal development projects in Hong Kong waters north of Lantau Island. Ecological acoustic recorders obtained 2711 days of recording at 13 sites from December 2012 to December 2014. Humpback dolphin sounds were manually detected on more than half of days with recordings at 12 sites, 8 of which were within proposed reclamation areas. Dolphin detection rates were greatest at Lung Kwu Chau, with other high-occurrence locations northeast of the Hong Kong International Airport and within the Lung Kwu Tan and Siu Ho Wan regions. Dolphin detection rates were greatest in summer and autumn (June-November) and were significantly reduced in spring (March-May) compared to other times of year. Click detection rates were significantly higher at night than during daylight hours. These findings suggest high use of many of the proposed reclamation/development areas by humpback dolphins, particularly at night, and demonstrate the value of long-term PAM for documenting spatial and temporal patterns in dolphin occurrence to help inform management decisions.
authors: Oceanwide Science Institute, P.O. Box 61692, Honolulu, Hawaii 96839, USA.
authors: Lisa
authors: L
authors: Munger
authors: Oceanwide Science Institute, P.O. Box 61692, Honolulu, Hawaii 96839, USA.
authors: Marc O
authors: MO
authors: Lammers
authors: Oceanwide Science Institute, P.O. Box 61692, Honolulu, Hawaii 96839, USA.
authors: Mattie
authors: M
authors: Cifuentes
authors: Department of Marine Biology, Texas A&M University, 200 Seawolf Parkway, OCSB #243, Galveston, Texas 77553, USA.
authors: Bernd
authors: B
authors: Würsig
authors: Clymene Enterprises, Lakeside, California 92040, USA.
authors: Thomas A
authors: TA
authors: Jefferson
authors: Hong Kong Cetacean Research Project, Lam Tin, Kowloon, Hong Kong.
authors: Samuel K
authors: SK
authors: Hung