Risk of extinction, variability in fish species composition, and factors influencing fish biodiversity in the Malacca Strait.

Fish biodiversity in Malaysia is under pressure due to overexploitation, pollution, and climatic stressors. Nevertheless, the information on fish biodiversity and species vulnerability status is not well documented in the region. Therefore, a study on fish species composition and abundance in the Malacca Strait of Malaysia has been conducted for the purpose of monitoring biodiversity, determining the risk of species extinction, and identifying factors influencing biodiversity distribution. The sampling was conducted based on a random stratified sampling method from the three zones of sampling locations, i.e., estuary, mangrove, and open sea area of Tanjung Karang and Port Klang of Malacca Strait. Higher species diversity was recorded at Tanjung Karang coastal and mangrove areas (H' = 2.71; H' = 1.64) than Port Klang coastal and mangrove areas (H' = 1.50, H' = 0.29), an indication that the Port Klang area is comparatively more vulnerable. The study also explored sampling location, habitat, and IUCN red list as the influencing factors for fish biodiversity. Applying IUCN red list, this study identified one Endangered and one Vulnerable species with the forecasted increasing landing for both species. Our findings suggest the urgent need for the implementation of conservation measures as well as the continuous monitoring of fish biodiversity in the area.

Investigating fish contamination scenario and community willingness to adopt consumption advice proposing an advisory option.

Consumption advice to ensure the health and safety of fish consumers remains urgent to handle the ever-increasing panic over heavy metal toxicity. Moreover, studies of fish consumption rarely focus on the perceptions and awareness of consumers. Considering this, the present study examines the factors determining the willingness to follow fish consumption advice as well as calculate the risk-benefit ratio and produce the vulnerability map followed by formulating fish consumption advice for consumers of two commercially important fish species, tilapia (Oreochromis niloticus) and mudfish (Ophiocephalus striatus), in the Laguna de Bay area of the Philippines. Primary data on consumers' perceptions were collected through a questionnaire, whereas heavy metal contamination data were compiled from the best available literature. We concluded that people's willingness to adopt consumption advice is mostly dependent on their existing level of fish consumption (P = 0.000). There was no discernible difference in the mean concentration of heavy metals in fish between the dry and wet seasons, with the exception of As concentrations in the samples (t15.75 = 3.72, p < 0.001). The hazard quotient (risk-benefit ratio) for fish consumption (HQefa) was an order of magnitude higher in the mudfish samples (0.05 and 28.28) compared to tilapia (0.04 to 16.02). Binangonan and Taguig from the Northern West Bay (1A, 1B) were clearly recognised on the vulnerability map as the most vulnerable regions in the lake. In general, it was determined that As and Pb were the elements causing consumption restrictions on tilapia collected from various parts of Laguna Lake. As with tilapia, locations with a high-risk advisory for mudfish were identified as the Northern West Bay and Central Bay, with a consumption limit of five meals per month due to excessive mercury pollution. This empirical study can serve as an option for the future development of fish consumption advice in the region.