Effect of pond plastic sheeting on water temperature and improved growth of fish in Dowa, Malawi
Abstract
214 words
Temperature is one of the limiting constraints to increasing fish
production in areas where temperatures are below 25oC. In
most areas in Malawi temperatures are between 14 - 24oC
(www.atlapedia.com/online/countries/malawi.htm), with the
exception of the lakeshore region. In search for a low cost
technology to increase water temperatures to boost tilapia
production, the effect of clear plastic sheeting on growth of
Tilapia rendalli was tested on station. Results showed that
covering 80 % of fish ponds using clear plastic resulted into a
growth increase by more than 50 % (Specific Growth Rate
(SGR) of 0.84). In absence of data on food availability and
unionized ammonia, it was presumed that clear plastic sheeting
acts as a greenhouse structure such as those that have been
noted to reduce heating requirements in geothermal heat pump
(GHP) systems by over 50%. Following these results, an on
farm experiment was initiated at two fish farms in Dowa
District, Malawi, in October 2008. Results from the initial and
second phases of the experiment showed that the plastic sheeting
had effect on temperature with highest temperature increase
in ponds with 50% cover, but with no obvious increase in fish
growth. The experiment will run for the third time in which
more explanatory variables, including food and nutritional
availability, will be investigated.
Subjects
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