Abstract:
The present study deals with an account of the results of an investigation
on plankton primary production using Oxygen technique in the coastal
waters of the western coast in Sri Lanka. Magnitude of primary production
and its monthly variations were studied. Factors governing the primary
production such as; transparency of water, temperature, phytoplankton
density, and dissolved nutrient concentration, their variation in time have
discussed and an attempt has been made to relate these parameters with
primary production. Mean photosynthetic rate measured over the continental
shelf of west coast was 0.944 g Cm2 dol.This would amount to an annual
gross production of344.0 g C m+Depth integrated total primary production
from the continental shelf of west coast for an area of 1050 km2 was 361830
tones. The present fish yield from the same area is around 2000 tones (200
tones in terms of Carbon), which is only 0.06 percent the Carbon produced
by primary production. Compare to intensely exploited waters where, 0.2-
0.3 percent of the primary production is harvest as fish, potential harvest
from the western shelf waters would be 31/2 to 5 1/2 times the present yield.
