Vol. 10, Issue 9 (2021)

Globally, the traditional practice of stocking natural waterbodies with fish seeds solely based on their surface area is not conducive to optimal fish production, as fish do not rely on drinking and inhabit the water. A more effective approach involves stocking these waterbodies according to their production potential. Magada’s Productivity Index Scale (MPIS) serves as a valuable tool for estimating the production potential of a given waterbody and determining the appropriate stocking density.

The MPIS incorporates easily measurable water quality parameters in the field, such as color, Secchi disc reading, WSA (Water Spread Area), mean depth, pH, level of weed infestation, and Water Retention Period (WR). Each parameter is scored on a distinct scale range. The PI value, which ranges up to 21.0, is a comprehensive indicator that considers these factors. Notably, depth, with a higher value given for depths exceeding 5 feet, does not negatively impact the Productivity Index (PI). However, depths beyond 5-6 feet exhibit reduced photosynthetic activity and are not considered due to their potential impact on productivity.

It's important to acknowledge that the PI scale is broad-based and may be influenced by various factors, including the presence of weed fishes, water inflow and outflow, natural calamities, water source, domestic utilization patterns, and more. Despite these potential influences, studies based on MPIS demonstrate a significant enhancement in production, exceeding 20%. While the production of a given tank is influenced by numerous parameters, MPIS serves as a guiding tool for augmenting fish production and is instrumental in achieving optimal results.