A portable electro-immobilization and laparoscopy system for sex determination and gonadal biopsy in largemouth bass Micropterus salmoides.

A portable electro-immobilization and laparoscopy system is described that is suitable for sex determination, gonadal biopsy and immediate release of largemouth bass Micropterus salmoides. Continuous direct current at a power density of 52·2 µW cm⁻¹ for 2 min was sufficient to immobilize fish for surgery, but induced a mild, transient hypokalaemia and hyperglycaemia. Insertion of a 4·8 mm laparoscopic instrument set through the urogenital pore provided access to the gonads for examination and biopsy with mild tissue trauma.