Growth of Scales in Goldfish

Abstract

Variations in circulus patterns of scales versus various physiological environments, namely the so-called scale rings, are the records of their life history. To analyze these records, studies were carried out on the formation of scale rings under physiologically restricted conditions using goldfish, Carassius auratus as material. The specimens of scales were taken from the dorsal and ventral sides of the lateral line scale (L-scale) at the level of the anterior end of the dorsal fin on the left body side. Seventy specimens from seven groups of the fish were collected. They were 0.5 to 2.5 years old and fed at 25°C or room temperature for 30 or 50 days. The specimens of scales were measured with respect to cranial radius, circulus number and circulus interval. The shape and size of the scales were a function of their position. The ones adjacent to L-scale were the largest and became smaller as they diverged from it. The distri-bution of relative size in regard to scale position had no relationship to body size. The growth rates of scale radius were larger in the scales which were located nearer to the L-scale. The specific growth rates were constant regardless of the scale position that varied with age or body size. The augmentations in circulus number were similar in character as to the growth of scales. The circulus intervals were narrower in the younger than in the older fish. For a specimen, the circulus interval in scales situated dorsally to the L-scale were narrower than those located ventrally.