Chinese white dolphins (also known as Indo-Pacific humpback dolphins, Sousa chinensis) inhabiting the Pearl River Estuary (PRE), including coastal waters of a portion of southern mainland China and adjacent waters around Hong Kong, face a number of severe threats. Among these threats are high-speed ferry operations, large-scale construction projects, fishing, and agricultural and industrial pollutants. As part of a larger Chinese White Dolphin Conservation Research Framework, a workshop was held during 30 March-1 April, 2016 in Hong Kong to initiate the development of a population viability analysis (PVA) to evaluate the current status of the PRE population and the risk of future population decline or extinction in the presence of human-induced threats.
To provide data to support the PVA and to facilitate long-term monitoring of the population, a collaborative effort among PRE Chinese white dolphin researchers and the SDRP is underway to adapt the Gulf of Mexico Dolphin Identification System (GoMDIS, see Cush, p.18) to improve population estimates, characterize life history parameters, and understand ranging patterns. This system will be known as PREDIS, Pearl River Estuary Dolphin Identification System. These animals can be identified not only by their dorsal fin markings, but their coloration as well. Young animals are darker in color, and as they grow will become more white/pink, yet retain identifiable spotting patterns on their bodies. The PREDIS system will allow the research groups to search animals using a combination of fin characterizations and coloration to conduct between-site matching. This will also allow them to keep their research interests separate but share necessary data for joint analyses.
The researchers are submitting basic metadata to standardize and combine their efforts for upload to an offline PREDIS database, modeled after GoMDIS, and images will be processed and uploaded to a collaborative online portal specifically for this group. This photo-ID platform will allow them to search other project catalogs, submit, circulate and confirm matches, as well as serve as a visual reference for the locations of the images submitted. We have received our first test set of data from St. Andrews University’s Sea Mammal Research Unit (SMRU) Hong Kong office, which we are using to modify the GoMDIS database for PREDIS.
This article appeared on pages 8-9 of the 2017 SDRP Annual Report, Nicks n Notches.