Fish Shoal Identification

Traditional ecological knowledge among coastal fishers reveals keen observation used for fish shoal identification. Fish shoals, known as polappu, are identified by color of water surface and appearance. For instance, a dark burgundy or jamun color on the water surface is often associated with the presence of sardines near the surface, while water appearing gray, black, or blue-black also signals the aggregation of fish. Different fish species exhibit unique traits that help in their identification. Mackerel are recognized by their white or silver-shaded bodies and a swimming style that creates a hump-like shape on the water surface, moving with a distinctive swing of the head and tail. Pomfret, particularly black pomfret (locally called Aavoli or Machan), are identified by their glittering white appearance, often seen in the shadows of boats, and swim rapidly. Local expressions like “Aavoli vellapadam virich varum” describe the visual patterns associated with their arrival. Shrimp, known for their copper color, are often seen jumping out of the water, while some rays also display similar jumping behavior. Anchovies are linked to brown or reddish-brown water and appear in dense shoals. Tuna, due to their fast movement and size, create a visible hump on the water surface when moving in large groups. The appearance of bubbles on a calm water surface further indicates fish presence. Seagulls circling or diving are strong indicators of fish shoals, as the birds feed on them and follow their movements. These traditional methods not only support efficient and targeted fishing but also reduce unnecessary effort and contribute to sustainable practices. Now the fish shoal identification is replaced by echo sounder like gadgets.