Fish Classification and Availability Quiz

Fish Classification

• Fish are scientifically known as Istiophorus Orientalis
• Classified into two categories: fish (vertebrates) and shellfish (invertebrates)
• Shellfish are further categorized into mollusks and crustaceans
• Mollusks have soft bodies and usually a shell (e.g., oysters, clams, scallops)
• Crustaceans have segmented bodies and hard shells (e.g., lobsters, crabs, shrimp)

Fish Availability

• Scaly fish varieties vary geographically and differ in flavor
• Availability of saltwater fish depends on finding large schools, not reliant on human cultivation
• Freshwater fish can also be farmed (aquaculture)
• Philippine aquaculture includes marine fish and bangus (milkfish)
• Mariculture (cultivating fish in salt water) is developing, focusing on oysters and tahong.

Fish as a Food Source

• Fish is a significant source of protein in the Philippines, often a low-cost alternative to other meats
• Fish protein contains all essential amino acids, implying a high biological value.

Fish After Death

• Fish caught die while in nets or shortly after removal from water (with exceptions of species with accessory breathing organs).
• Deteriorative changes happen after death, impacting edibility
• Initial changes include soft, gel-like, sticky muscle tissue, followed by rigor mortis (muscle rigidity)
• Spoilage is caused primarily by fish enzymes and bacteria, often originating from slime or internal organs.
• Trimethylamine oxide in living fish flesh converts to trimethylamine, contributing to the stale fish odor.
• Oxidative deterioration occurs, affecting fish fat (rancidity)

Nutritional Value of Fish

• Fish is a high-quality protein source (18-20%)
• Contains essential amino acids in balanced proportions
• Specific types of fish (e.g., apahap, lapu-lapu, labahita) have notably high protein.
• Fish fat content is generally low (less than 1% in most types), with varying distribution throughout the fish.

Fresh vs. Stale Fish (Characteristics)

• Fresh Fish: Shiny, bright, full eyes, bright red gills, firm flesh, fresh odor.
• Stale Fish: Dull eyes, wrinkled skin, dull/brown/gray gills, soft/flabby flesh, foul odor.

Fish Preparation (Market Forms)

• Live fish (whole): Transported and sold alive.
• Dressed fish (whole): Scaled, gutted, and finned fish.
• Butterfly fillets: Cut lengthwise through the center and held together.
• Filets: Boneless pieces cut from the side of the fish.
• Steaks: Slices of fish cut across the backbone.
• Sticks: Uniform pieces of fish (often frozen).

Fish Cooking Methods

• Cooking fish destroys harmful bacteria and improves flavor and tenderness.
• Moderate cooking temperatures are used
• Dry cooking methods (e.g., broiling, baking, frying) are suitable for fish that are not too fatty.
• Moist cooking (e.g., boiling) is suitable mainly for fatty fish, but can lead to falling-apart flesh with prolonged boiling.
• Cooking time is variable, depending on thickness and cooking method. Determining doneness depends on opaque white flaking/crumbly flesh.