Biology of commercial food fishes of Pakistan, their morphology, anatomy, systematic, ecology and distribution, physiology of digestion (food, feeding habits, factors affecting food consumption, digestion, absorption, conversion), body composition (water, protein, fats, carbohydrates and minerals in freshwater and marine fishes), nutrition and growth (dietary requirement, measurement of growth, factors affecting growth rates)  sex differences, sexual maturity, fecundity, fish migration