Spatio-Temporal Variation in the Exceedance of Enterococci in Lake Burley Griffin: An Analysis of 16 Years' Recreational Water Quality Monitoring Data.

Recreational waterbodies with high levels of faecal indicator bacteria (FIB) pose health risks and are an ongoing challenge for urban-lake managers. Lake Burley Griffin (LBG) in the Australian Capital city of Canberra is a popular site for water-based recreation, but analyses of seasonal and long-term patterns in enterococci that exceed alert levels (>200 CFU per 100 mL, leading to site closures) are lacking. This study analysed enterococci concentrations from seven recreational sites from 2001-2021 to examine spatial and temporal patterns in exceedances during the swimming season (October-April), when exposure is highest. The enterococci concentrations varied significantly across sites and in the summer months. The frequency of the exceedances was higher in the 2009-2015 period than in the 2001-2005 and 2015-2021 periods. The odds of alert-level concentrations were greater in November, December, and February compared to October. The odds of exceedance were higher at the Weston Park East site (swimming beach) and lower at the Ferry Terminal and Weston Park West site compared to the East Basin site. This preliminary examination highlights the need for site-specific assessments of environmental and management-related factors that may impact the public health risks of using the lake, such as inflows, turbidity, and climatic conditions. The insights from this study confirm the need for targeted monitoring efforts during high-risk months and at specific sites. The study also advocates for implementing measures to minimise faecal pollution at its sources.

Landmark-based morphometric and meristic variations of freshwater garfish, Xenentodon cancila from four natural stocks of South-Western Bangladesh.

OBJECTIVE: The morphometric and meristic variations of Xenentodon cancila was studied based on the landmark-based truss network system to assess their phenotypic variations among four different freshwater stocks, viz. Boluhorpur baor, Jhenaidah (BBJ) (n = 29); Bhairab River, Jashore (BRJ) (n = 34); Arial Khan River, Madaripur (AKRM) (n = 28), and Bohnni baor, Gopalganj (BBG) (n = 25) in Bangladesh. MATERIALS AND METHODS: Seven meristic characters were counted by using a needle. Eight morphometrics and 28 truss measurements were measured by using tpsDigV.2.1 software. In meristic characters, Kruskal-Wallis test was performed to determine any significant differences, whereas, in morphometrics and truss measurements, univariate statistics and discriminant function analyses were carried out by using SPSS 22 version. RESULTS: Significant differences were observed in four meristic characters among seven meristic characters in the Kruskal-Wallis test. In univariate statistics, only nine characters were observed significantly different among eight morphometrics and 28 truss measurements. The contribution of three discriminant function analyses (DFA), in which first DFA showed 49.2%, second DFA showed 33%, and third DFA showed 17.8% on behalf of both morphometric and truss measurements. In discriminant space, the four stocks were clearly separated. Two clusters were formed among four stocks, where BBG formed a single cluster, whereas BBJ and BRJ aggregately formed another cluster. Additionally, AKRM formed a sub-cluster with BBJ. CONCLUSION: The preliminary information generated from the current study would be beneficial for further genetic studies and in the assessment of ecological impacts on X. cancila stocks in Bangladesh.