UG researcher leading efforts to ensure sustainable fish farming

Lecturer at the University of Guyana, Samantha Forrester, an aquaculturist, has been leading the way with her remarkable work in safeguarding the health of fish and ensuring they are reared in a sustainable manner.
Forrester is also a researcher attached to UG’s Faculty of Agriculture and Forestry for over nine years. In a release on Friday, the University of Guyana said that Forrester holds a Bachelor of Science in Agriculture from the University of Guyana and a Master of Science in Fisheries Science from Nanjing Agricultural University in China, the world’s top fish producer. “With support from UG, I was selected for the MOFCOM Scholarship, and the University of Guyana granted me study leave to bolster my research,” she explained.
Driven by the adage, ‘we are what we eat’, Forrester embarked on a quest to safeguard the health of fishes and their immune systems. “Over the years, the demand for meat products, particularly fish, has increased as people become more health-conscious about their diets,” she noted.
This shift inspired Forrester to investigate culturing fish in ponds and tanks for commercial purposes. Her research indicated that cultivating a large number of fish in confined spaces increases their susceptibility to stressors, such as bacterial pathogens.
“Aeromonas hydrophila is a bacterial pathogen that seriously affects the aquaculture industry globally, causing massive economic losses due to the high mortality rate of infected fishes. To combat these bacterial diseases, several veterinary drugs are used, but many contain harmful chemical compounds that pollute the aquatic environment and accumulate as residue in the fish’s tissue,” the researcher explained.
In response, Forrester investigated a local medicinal herb which is an alternative source to antibiotics and is known for its medicinal properties. “I conducted an in-vitro study to determine the antibacterial properties of herbs effective in treating Aeromonas hydrophila,” she proudly reflected.
After observing positive results from the herbs, Forrester formulated a basal diet to feed the fish daily. Using crucian carp for her study, she noted: “We tested five groups, each containing twenty fishes chosen at random. One group received only the basal diet as the control, while the other four groups were given the basal diet with herb extract added at varying potencies over eight weeks.”

She further explained that after eight weeks, a subset of fishes from each group was exposed to a known concentration of the bacterium. Further observations, testing, and statistical analysis followed, leading to conclusive results. The study revealed that the herb extract enhanced the fishes’ physiological and immune functions and enhanced resistance against pathogenic infections in Crucian carp.
Forrester’s research suggests that natural immunostimulants of plant origin may serve as viable alternatives to veterinary drugs containing harmful chemicals in aquaculture. She hopes her work will enhance the sustainability of fish farming as a livelihood while increasing the nutritional value of fish for consumers. Currently, she is focused on expanding her research portfolio in the areas of proximate analysis of selected plant species used in aquaculture and microbiological assessment of farmed fish and shrimp.