Environmental and Microbiome Profiling of Aquaculture Farms in the Central region of Ghana

Speaker: Dr. Cynthia Adinortey
Africa-UBC Oceans and Fisheries Visiting Fellow (Cohort 1)

Fish production in Ghana comes mainly from marine catch, followed by inland catch, and aquaculture contributing the least. As marine stocks have declined over the past decades, measures such as closed fishing seasons and promotion of aquaculture have been introduced. Despite aquaculture’s great potential, it is the least contributor to the country’s fish production due to challenges such as high fish mortality from infections. Such losses could be reduced through proper fish health monitoring, including water safety checks. While some studies have reported bacterial and fungal pathogens in cultured fish and feed in Ghana, there is limited documentation on pathogens, contaminants, and disease management methods employed in aquaculture settings. This study was therefore conducted to assess the environmental and microbiome profiling of fish farms in the Central region of Ghana.

The study employed a cross-sectional, experimental design comprising a structured questionnaire, physicochemical water measurements, GC-MS screening and culture-independent DNA analysis. While feed and sediment samples were subjected to GC-MS, DNA extracts recovered from water, fish, feed and sediment samples were subjected to PCR using broad bacterial 16S and eukaryotic 18S targets primers and selected DNA extracts from farms were subjected to metagenomic sequencing. Four pond-based catfish farms (A, B, C and D with Farm D growing in addition Nile tilapia) comprising 12 ponds varied in operation duration, water sources, water reuse, and farm practices; only Farm B reported rare disease outbreaks and oxytetracycline use. Water quality showed stable temperature and pH but wide dissolved oxygen and turbidity ranges, with notable extremes in Farm D ponds. PCR amplicons of bacterial 16S and eukaryotic 18S rRNA genes were obtained  and GC-MS analysis of feeds  and Farm D sediments revealed mainly hydrocarbon-like compounds and 13-docosenamide. The extreme dissolved oxygen (0.26–21.62 mg/L) and turbidity (up to 1,000 NTU) values suggest unstable pond conditions that can stress fish, predispose them to disease, which could promote antimicrobial use. The low-oxygen earthen ponds and the supersaturated tarpaulin tank pond warrant specific management attention. Although the dominance of hydrocarbon-like compounds and across feeds and sediments is not evidence of antibiotics, the presence of 13-docosenamide can suppress essential nitrifying bacteria which are critical for the nitrogen cycle in fish ponds because they break down toxic ammonia into harmless nitrates. This calls for better characterization and regulation of feed and sediments in aquaculture settings. Pending data on metagenomic sequencing of DNA extracts would help obtain the microbiome profiling  of study sites.

In addition to the research a policy paper on Antimicrobial Resistance and aquaculture in Ghana is currently being drafted.

Biography
Cynthia A. Adinortey (PhD, PGDE) is an Associate Professor at the University of Cape Coast (UCC) in Ghana, where she obtained her PhD in Molecular Biology and Biotechnology. Her research centers on understanding bacterial virulence and antibiotic resistance, with a focus on food safety and the fisheries value chain, using the one health approach.

As a passionate STEM advocate and Antimicrobial Resistance awareness campaigner and researcher, she often engages in community service through radio interviews, outreach at schools and STEM hands-on sessions. She has a keen interest in mentoring and training the next generation scientists. Since 2017, she has worked with key stakeholders in Ghana’s fisheries sector, providing microbiology expertise on four major projects. These include research on polycyclic aromatic hydrocarbons in fish, the Healthier Smoked Fish Certification Scheme under USAID’s Sustainable Fisheries Management Program (SFMP) and the development of the Safe Fish Certification Scheme with Feed the Future Ghana Fisheries Recovery Activity (GFRA). In 2019, she led a USAID/UCC project on antibiotic resistance in Ghana’s aquaculture sector. Between 2021-2023, Cynthia was a member, of the inaugural cohort of mBio Junior Editorial Board, and subsequently served as a Mentor for the second cohort of mBio Early Career Editors. She currently serves as an Editor for mBio. In 2022, she was selected an affiliate of the African Academy of Sciences. In 2024, she was selected as one of the two Africa-UBC Oceans and Fisheries Visiting Fellows at the University of British Columbia (Canada). In 2025, she was a Fulbright Scholar-in-Residence at the University of North Carolina, Asheville (USA).

Cynthia served as the Cape Coast branch Treasurer of the Ghana Science Association from 2015 to 2019. She currently serves as Convenor of the Graduate women International Hegg Hoffet Committee and Coordinator of International relations for the Ghana Association of University Women. She belongs to other professional bodies including: American Society for Microbiology, International network of Women Engineers and Scientists (INWES), Mothers in Science and Organization for Women in Science for the Developing World (OWSD).

Location: AERL Theatre, 2202 Main Mall, UBC Vancouver or over ZOOM. RSVP Required
https://oceans.ubc.ca/news-and-events/iof-seminars/weekly-seminars/