An Assessment of Productivity Levels in a Freshwater System Located in Thanjavur District, Tamil Nadu in the Context of Aquaculture
R. Sivakami *
PG. and Research Department of Zoology, Arignar Anna Government Arts College, (Affiliated to Bharathidasan University), Musiri – 621 211, Tiruchirappalli, India.
A. R. Nazar
PG. and Research Department of Zoology, Arignar Anna Government Arts College, (Affiliated to Bharathidasan University), Musiri – 621 211, Tiruchirappalli, India.
V. Babu
PG Department of Microbiology, Valliammai Women's College of Arts and Science (Affiliated to the Annamalai University), Arakandanallur, Villupuram (DT), Tamilnadu - 605 752, India.
A. Rajendiran
PG. and Research Department of Zoology, Arignar Anna Government Arts College, (Affiliated to Bharathidasan University), Musiri – 621 211, Tiruchirappalli, India.
*Author to whom correspondence should be addressed.
Abstract
Background: Primary productivity is an important indicator of the energy available to support aquatic organisms and is relevant when assessing the suitability of freshwater ponds for fish culture.
Aim: This study assessed seasonal variation in productivity in a perennial freshwater pond at Swamimalai, Thanjavur District, Tamil Nadu.
Methods: Primary productivity was measured monthly during 2025–2026 using the light-and-dark-bottle technique. Bottles were incubated for 12 h, from 06:00 to 18:00 h, and changes in dissolved oxygen were used to estimate gross primary productivity (GPP), net primary productivity (NPP) and community respiration (CR).
Results: During the first year, GPP ranged from 6.6 to 10.3 gC/m²/day, NPP from 4.2 to 6.6 gC/m²/day and CR from 2.4 to 3.8 gC/m²/day. During the second year, the corresponding ranges were 7.1–10.5, 4.3–6.8 and 2.8–4.0 gC/m²/day. Across both years, the minimum values of GPP, NPP and CR were recorded in January, whereas their maximum values occurred in May. The seasonal alignment of these productivity measures indicates variation in photosynthetic production and community oxygen demand over the study period.
Conclusion: The findings indicate measurable autotrophic production in the pond and support its potential usefulness for fish culture. However, productivity should be interpreted alongside water quality, nutrient conditions, plankton composition and other management-related factors when evaluating aquaculture suitability.
Keywords: Seasonal variations, fresh water pond, gross primary productivity, net primary production, community respiration