Variation in growth, condition, physiological and prey-predator status of smoothbelly sardinella, Amblygaster leiogaster (Valenciennes, 1847) in the Bay of Bengal

Abstract

This study estimated the first report on temporal and seasonal variation in growth patterns, condition factors (Fulton’s, K_F; Relative, K_R), physiological and prey-predator status of Amblygaster leiogaster (Valenciennes, 1847) from the Bay of Bengal, Bangladesh through sampling from January to December 2020. Collected individuals (1337) were measured with an accuracy of 0.01 g for body weight (BW) and 0.1 cm for total length (TL), respectively. The growth pattern was evaluated through studying the length-weight relationships. The study recorded new maximum length (30.50 cm TL) and weight (142.56 g) for this species. This species revealed an overall negative allometric (b = 2.61) growth. Temporal variation indicated a positive allometric growth in September, October and November. However, an isometric growth pattern (b = 3.08) was found in post-monsoon while other season demonstrated negative allometric growth. The overall K_F was 0.50–1.20, and K_R was 0.66–1.35 for A. leiogaster. The overall K_F showed a strong correlation with TL, while the K_R demonstrated correlations with both TL and BW. Most of the fatty fish found in winter (51.43 %) with a minimum number of lean fish (21.14 %) while maximum ideal fish was in post-monsoon (55.77 %). The W_R stated that the Bay of Bengal had been considered stable for A. leiogaster. The findings provided valuable insights on the stock health of A. leiogaster that assist in developing efficient management in the Bay of Bengal and other habitats.