Light and scanning electron microscopic studies on the effect of biocidal plant sap on the gills of a hill stream fish, Garra lamta (Ham.)

Abstract

The effect of a biocidal plant sap (Terminalia tomentosa) on the gills of a swift‐current‐adapted hill‐stream fish, Garra lamia, has been investigated using light and scanning electron microscopy. The biocidal plant sap affected the dissociation of the gill filament and lamellar epithelia to expose their microvasculature. Some findings on the microvasculature are discussed in the light of their probable functions. Fusion of lamellae and prominent chloride cells are further effects of the plant sap, and their impact on respiratory and osmoregulatory functions of the fish are discussed.Use of biocidal plant sap in mass killing of hill‐stream fish is considered in relation to conservation.