Nutritional aspects

Why do consumers buy fish? TastyConvenient Good value Healthy and nutritious

Health and seafood Seen as healthy option Good source of protein Low-fat no fat Source of the Omega 3 fatty acids Oily fish contain n-3 fatty acids (also known as omega-3 fatty acids) and vitamins A and D. Oily fish contain n-3 fatty acids (also known as omega-3 fatty acids) and vitamins A and D.

perceptions of health vary with seafood categories More Healthy Less Healthy Oil rich fish Fresh White fish Frozen Processed Shellfish Natural

Composition of fish Lean fish e.g. Cod Water 78 – 83% Protein % Fat 1 - 4% Fatty fish e.g. Mackerel Water % Protein % Fat %

Fish muscle

Cross section through body of fish

Water 70 – 80% weight of white fish fillet 70% of fatty fish fillet

Protein 15 to 20 % of body weight Amino acids: lysinemethionine found in high concentrations found in high concentrations complement cereal protein in diet. complement cereal protein in diet.

Fat Not distributed evenly throughout the flesh of the fish. Concentrated in dark muscle of fatty fish.

Fish oil Extracted from whole fish High in poly unsaturated fatty acids Used for: Margarines and shortenings

Fish oil 2 Extracted from fish liver Cod liver oil Vitamin A Vitamin A Vitamin D Vitamin D Omega-3 fatty acids (EPA and DHA). Omega-3 fatty acids (EPA and DHA).

The minor components of fish muscle Carbohydrates Minerals and Vitamins

Mercury in Fish Bad fish, good fish Fish most likely to contain mercury: Shark Swordfish King mackerel Tilefish Albacore tuna Shark Swordfish King mackerel Tilefish Albacore tuna Fish known to be low in mercury: Shrimp Canned light tuna Salmon Pollock Catfish Shrimp Canned light tuna Salmon Pollock Catfish Source: FDA/EPA

Factors affecting the composition of fish Fishing ground Season Food supply