Fish and crustacean biodiversity in an outer maritime estuary of the Pearl River Delta revealed by environmental DNA.

Understanding the faunal community structure in the estuary would be crucial in assessing the health of the ecosystem. The poor visibility in the estuarine area due to the outflow from the Pearl River hinders the conventional visual census in assessing the megafaunal biodiversity. In this study, the fish and crustacean biodiversity of Hong Kong's western waters, i.e. the outer maritime estuary of the PRD, were studied through the metabarcoding of environmental DNA (eDNA). eDNA from the seawater and sediment samples was extracted from five sites in the region. After testing the performance of two genetic markers, amplicons of the cytochrome oxidase I, amplified by polymerase chain reaction, were subjected to Illumina high-throughput sequencing (MiSeq) analysis. A total of 22 fish species from 17 families and 34 crustacean species from 27 families were identified by blasting the sequences against the NCBI GenBank database, demonstrating segregation between samples from different sites. This study provides insight on the detail distribution of fish assembly in PRD, when compared with a previous eDNA study in the inner brackish PRD.

Shark Conservation: An Educational Approach Based on Children's Knowledge and Perceptions toward Sharks.

Shark conservation has become a focus of current international conservation efforts. However, the misunderstanding of sharks and their negative public portrayal may hinder their conservation. More importantly, the consumption of shark fin, which is very common in Chinese cultures, poses a significant threat to sharks. Hong Kong has long been the world's largest shark fin trading center. Shark conservation would become more sustainable if public understanding of this predatory fish and an appreciation of its ecological significance could be promoted. It is possible that the demand for fins could be effectively managed through long-term educational efforts targeted at younger generations. To provide essential baseline data for planning of these educational efforts, this project investigated the perceptions of 11 to 12 year-old primary school students in Hong Kong about sharks, and their understanding of ecological concepts and shark-related knowledge. The findings indicate that these students lack sufficient knowledge and possess misconceptions about sharks and their ecological significance in the marine ecosystem. The students' conceptual understanding level is strongly correlated with their perceptions. Correlational analyses further demonstrated a positive association between formal education and perceptions toward shark conservation. The students who favoured shark fin consumption did so because of its tastiness, whereas concerns about shark population decline and the cruelty of shark hunting were the main reasons for not favoring shark fin consumption. This pilot study provides preliminary but important insights into primary school education regarding the conservation of sharks.