1. Information gaps from uninvestigated habitats can hinder population assessments and the efficacy of conservation actions for marine mammals, particularly for populations of widely distributed species. The full extent of occurrence of the world's largest (putative) population of Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River estuary (PRE) is not known due to a poor understanding of the western boundary of the population's range. This information gap is the basis of the most critical obstacle for assessing the population's status. 2. To determine the distribution and abundance of the PRE humpback dolphins in the far western portion of its range, systematic line-transect vessel surveys were conducted in the Moyang River estuary (MRE) during 2013-2015. Photo identification of dolphins and cross-matching of individual dolphins between different regions were also undertaken to examine individual movement patterns. 3. The abundance of humpback dolphins in the MRE was estimated to be 528 individuals (coefficient of variation: 28.7-50.2%). 4. Cross-matching of individually identified dolphins from the MRE (present survey area) with those from other survey areas of the PRE showed that dolphins moved frequently across different regions of the PRE, indicating dolphins from both PRE and MRE comprise a single population (which is renamed to be the PRE-MRE population). The western boundary of this population appears to be in the waters on the eastern side of Hailing Island, as dolphins were never observed further west. 5. Supporting around one-fifth of the PRE-MRE population and providing a quarter of the habitat of the entire PRE-MRE population, the MRE clearly also deserves consideration for greater conservation measures. Strengthening the management with stringent controls over fishing activities in the MRE and establishing a marine protected area in the core habitat are recommended to facilitate better conservation for the entire PRE-MRE humpback dolphin population.

Pathogen and stress-related morbidities are the main challenges in tilapia farming. Improving the immune health is an effective approach to protect tilapia against these pathogens. Phenolic content and antioxidant activity of rice husk (RH), sugarcane bagasse (SB), and corn cob (CC) evaluated by Folin-Ciocalteau assay and DPPH assay revealed high total phenolic content and antioxidant activity in RH compared to CC and SB. LCMS analysis of RH, SB, and CC exhibited the presence of hydroxybenzoic acid and hydroxycinnamic acid in agricultural waste samples. Effects of RH, SB, and CC on growth performance, gut microbial flora, innate immunity, and hematology of hybrid red tilapia (Oreochromis aureus X Oreochromis mossambicus) were evaluated in 91 days feeding trial with a test diet supplemented with 10% RH, SB, CC to basal diet (BD) ingredients in optimum conditions of growth. Growth performance data was recorded at an interval of 13 days. At the end of feeding trial, fish gut microflora, skin mucus bactericidal activity, blood serum lysozyme, and bactericidal activity against Shigella sonnei, and hematological parameters were evaluated. Significant difference in growth performance of red tilapia fed with experimental diets was observed. RGR (relative growth rate) was lowest in BD (380.79 ± 46.26) and observed highest in RH (554.01 ± 83.24). Lactobacillus count was increased in all experimental groups. Decrease in Salmonella sp., Shigella sp., and E. coli count was observed in CC. All experimental groups showed enhanced serum bactericidal activity against Shigella sonnei. SB group showed the highest serum bactericidal activity. Skin mucus bactericidal activity was also highest in SB. Least skin mucus bactericidal activity was presented by BD. Results of research work indicated that RH, SB, and CC have bioactive ingredients that positively influenced the growth performance, innate immune response, and hematology of red tilapia. Agricultural by-products are abundant biomass and rich in bioactive and nutraceutical compounds, therefore these are good candidates for maintaining redox balance, health status and growth performance in fish.