Full text can be accessed at http://www.sciencedirect.com/science/article/pii/S0254629915311686Samples were collected monthly from Oyster Bay, Dar es Salaam. Light, temperature, salinity, pH, seawater nitrogen and phosphorus were determined on each sampling period. Mean carrageenan yield was significanlly higher during the SE monsoon period (t = 6.15, P<0.05). Gef strength was significantly higher during NE monsoon period (t = 2.61, P<0.05) and lower during the start of the rainy season particularly in March.