Disease outbreaks in shrimp culture systems of Sri Lanka has resulted in a 35 to 70% reduction in production at farih Sites. Several critical water quality parameters (Salinity: 2-31 ppi; sulphides: 0.24-0.67 mg/l; Nitrites: 09-36 mg/l; total suspended solids: 80-160 tng/l) in the main water source (Dutch canal) were at sub-optimal ranges during disease outbreaks.
Microfouling on shells, reduced moulting, black gill syttdrome were the most commonly recorded symptoms. Infestations by Monodoh BacUlovirus (MBV) and peritrichous edocommensal Zoothamnium sp. were common in affected farms.
Accumulation of iron in-between gill lamellae and on litnellat cuticle was" confirmed by Scanning Electron Micrography (SEM),, Transmission Electron Micrography (TEM) and by histochemical studies, p Several hlsto- pathological changes were obsen’ed in gill, hepatopancriatic andhtydcdrdial tissues.