Fish Anatomy and Composition

Fish Composition

• Fish is a good source of protein and energy, comparable to meat.
• Saltwater fish are high in iodine and phosphorus, but lower in iron and calcium compared to freshwater fish.
• Canned fish has a higher calcium content than other types.

Fish Structure

• Fish are divided into four main parts: head, body, tail, and fins.
• 63% to 65% of a fish is considered edible, consisting primarily of flesh and skin.

Inedible Portions of Fish

• 35% to 38% of a fish is inedible, including the skeleton, tail, entrails, fins, and parts of the head and entrails.
• Some cultures utilize inedible portions in cooking.

Components of Fish Flesh

• Muscular Tissues: Made up of bundles of white muscle fibers.
• Connective Tissues: Found between muscle fibers, these tissues are called mycommata.
• Fat: Fish store fat for energy; fat content varies with season, diet, size, and age.
  • Fat Fish > 5% to 20% fat
  • Medium Fat Fish > 2% to 5% fat
  • Lean Fish > Less than 2% fat.

Fish Spoilage

• Fish spoils faster than meat due to bacteria and enzymes present in the intestinal system, which break down the flesh after rigor mortis.

Typical Finfish Composition

• Contains up to 84% moisture
• Has 15% to 25% protein
• Fat content ranges from 0.1% to 5.7%
• Carbohydrates comprise 1% to 3.5% of a typical finfish.