According to Murray and Eltholth (2018) the pond culture of Penaeus vannamei in Andhra Pradesh is practiced from freshwater (0 salinity) to brackishwater (up to 30 ppt)… however, the average salinity for culturing P. vannamei in Andhra Pradesh is 10 ppt.
Adjustment of pond salinity is by mixing from different water source as reported by Murray (2018) e.g. ground water (borehole) and surface water (canal, river, tidal creek, coastal seawater).
With regards to shrimp farm size, small-scale shrimp farming is the most common in Andhra Pradesh according to Srinivas et al. (2016).
https://www.imedpub.com/articles/sustainability-of-exotic-shrimp-ilitopenaeus-vannameii-boone-1931-farming-in-coastal-andhra-pradesh-india-problems-and-issues.pdf45 (See Page 82, Nursery, Culture, and Feeding Practices, 3rd Paragraph, 2nd Sentence)