Waterborne metal uptake has been extensively studied and dietary metal assimilation is increasingly recognized in fish, whilst the interaction between the two uptake routes is largely overlooked. This study compared the waterborne Cu bioaccumulation (⁶⁵Cu as tracer) in a juvenile rabbitfish at different feeding regimes (starvation (SG), feeding normal diet (NDG) or diet supplemented with extra Cu (DCG)) to test the hypothesis that feeding can influence waterborne metal uptake in marine fish. NDG and DCG diet was fed as a single meal and then all fish were exposed to waterborne ⁶⁵Cu for 48 h, during which the time course sampling was conducted to determine ⁶⁵Cu bioaccumulation, chyme flow and dietary Cu assimilation. The results revealed that SG fish accumulated the highest ⁶⁵Cu, followed by NDG (61% of SG), whilst DCG fish accumulated the lowest ⁶⁵Cu (34% of SG). These results suggested a protective effect of feeding against waterborne Cu bioaccumulation. This effect was most notable between 10 min and 16 h when there was chyme in gastrointestinal tract (GT). Dietary Cu assimilation mainly occurred before 16 h after feeding. Waterborne ⁶⁵Cu influx rate in the GT was positively correlated with ⁶⁵Cu contents of chyme in NDG, whereas it was largely negatively correlated with ⁶⁵Cu contents of chyme in DCG. The waterborne Cu uptake in the GT was mainly influenced by the chyme flow and dietary Cu assimilation. Overall, our findings suggested that feeding has an important effect on waterborne metal uptake and that both the feeding status of the fish and the relative metal exposure through water and food should be considered in prediction of the metal bioaccumulation and biomonitoring programs.

Our understanding of global seagrass ecosystems comes largely from regions characterized by human impacts with limited data from habitats defined as notionally pristine. Seagrass assessments also largely focus on shallow-water coastal habitats with comparatively few studies on offshore deep-water seagrasses. We satellite tracked green turtles (Chelonia mydas), which are known to forage on seagrasses, to a remote, pristine deep-water environment in the Western Indian Ocean, the Great Chagos Bank, which lies in the heart of one of the world's largest marine protected areas (MPAs). Subsequently we used in-situ SCUBA and baited video surveys to survey the day-time sites occupied by turtles and discovered extensive monospecific seagrass meadows of Thalassodendron ciliatum. At three sites that extended over 128 km, mean seagrass cover was 74% (mean range 67–88% across the 3 sites at depths to 29 m. The mean species richness of fish in seagrass meadows was 11 species per site (mean range 8–14 across the 3 sites). High fish abundance (e.g. Siganus sutor: mean MaxN.site−1 = 38.0, SD = 53.7, n = 5) and large predatory shark (Carcharhinus amblyrhynchos) (mean MaxN.site−1 = 1.5, SD = 0.4, n = 5) were recorded at all sites. Such observations of seagrass meadows with large top predators, are limited in the literature. Given that the Great Chagos Bank extends over approximately 12,500 km2 and many other large deep submerged banks exist across the world's oceans, our results suggest that deep-water seagrass may be far more abundant than previously suspected.

Jakarta Bay in Indonesia and its offshore island chain, the Thousand Islands, are facing extreme pollution. Surfactants and diesel-borne compounds from sewage and bilge water discharges are common pollutants. However, knowledge of their effects on reef fish physiology is scarce. This study investigated combined and single effects of a) the water accommodated fraction of diesel (WAF-D, determined by ƩEPA polycyclic aromatic hydrocarbons (PAHs)) and b) the surfactant linear alkylbenzene sulfonate (LAS) on metabolic performance of the coral reef fish Siganus guttatus. Responses to combinations of each pollutant with elevated temperature (+3°C) were determined. Short-term exposure to WAF-D led to a significant decrease in standard metabolic rates, while LAS led to an increase. During combined exposure, metabolic depression was observed. Effects of pollutants were not amplified by elevated temperature. This study highlights the need to reduce import of these pollutants and to avoid negative long-term effects on fish health.

Microplastics are a global concern, and yet, Philippine studies about it are still wanting. This study investigated microplastic ingestion among detritus-feeding mullet versus the herbivorous rabbitfish, and between freshwater and marine fishes. The first part aimed to compare microplastics in fishes’ guts differing in feeding guilds, individual sizes, and body weights. The second part compared MPs in fishes’ guts and their surrounding waters. Part one revealed that herbivores (58.57%) ingested more MPs than their detritivore-counterparts (30.0%). Pearson correlation, averaging 0.06, suggests a weak correlation between fish weight and MPs amount for both species. Part two showed marine fishes (66.0%) ingested more MPs than its freshwater counterparts (45.0%). A very weak correlation was observed between fish weight and amount of MPs ingested. Fish along the estuary ingested more MPs than those in other stations. No significant differences (p = 0.23) between the MPs in the water samples from each sampling stations was found.

Our previous study in 2011 reported the detection of BPA and PFAAs in 20 species of marine and freshwater fishes. With an emerging evidence to suggest the metabolic-disrupting effects of BPA/PFAAs in animals, the present study was aimed to provide a time-trend analysis to determine the current concentrations of PFAAs and BPA in 20 commercially available Hong Kong species of fishes. Since the manufacture and use of BPA is being prohibited in most nations, the introduction of BPA alternatives has recently been incorporated in the markets. Therefore, the concentrations of BPB, BPF and BPS were determined. In the present study, all freshwater and seawater fish samples showed quantified concentrations [>Limit of Quantification (LOQ<0.5ng/g)] of BPA. BPF was detected in some marine (yellow seafin, bigeye, goldspotted rabbitfish, snubnose pompano, tongue sole, Bleeker's grouper and orange-spotted grouper) and freshwater fishes (mud carp, crucian carp, tilapia, catfish, mandarin fish, grass carp, grey mullet and spotted snakehead). Two of the compounds, BPS and BPB could only be identified in the marine fishes (snubnose pompano, yellow seafin). In PFAA analysis, PFOA, PFDA, PFOS, PFUdA and PFDoA were found in most of the marine and freshwater fishes. PFOS and PFOA were shown to be the two predominant PFAAs in fishes. On the basis of the measured concentrations of bisphenols, BPs (BPA, BPB, BPF, BPS) and PFAAs, the average daily intake for BPs (20.5–31.5ng/kgb.w./day) and PFAAs (1.17–1.83ng/kgb.w./day) were calculated and found to be lower than values of tolerable daily intake (TDI) established in Europe. However, as compared with our previous study in 2011, the present study revealed an approximate 10-fold increase in the concentrations of BPA in the fish samples. Although the hazard ratio of consuming fishes for BPA and PFAA exposure is expected to remain low, possible additive metabolic-disrupting effect of BPA and its analogues as well PFAAs should be taken into consideration for human health risk assessment.

Mercury (Hg) exposure represents a significant public health concern at a global level. This study aims at assessing Hg exposure and risk among Lebanese young adults based on Hg biomonitoring and seafood intake. A group of 166 young adults were administered a questionnaire to assess Hg exposure and were asked to provide a hair sample. Risk assessment was performed: (1) using the US Environmental Protection Agency Hazard Quotient (HQ) model based on fish intake and previously studied local fish Hg concentrations, and (2) by determining the total hair Hg concentration (THHg) using continuous flow-chemical vapor generation atomic absorption spectrometry. Differences in THHg across demographic and exposure subgroups were tested using t test or ANOVA. Correlations between THHg concentrations, fish consumption, and HQ were determined by computing Pearson’s r. Higher THHg correlated with higher consumption of Mediterranean rabbitfish/spinefoots (r = 0.27; p = 0.001) and geographical location (p < 0.001) in the bivariate analysis, and remained significant in the adjusted multivariable linear regression model (geographical location: ß = 0.255, 95%CI 0.121–0.388; rabbitfish/spinefoots consumption: ß = 0.016, 95%CI 0.004–0.027). No significant correlations were found between HQ and THHg. In conclusion, this is the first study examining hair Hg levels and fish consumption in a young adult Lebanese population. Our findings constitute valuable baseline data for a local fish advisory and Hg monitoring.