Food and feeding habits of ribbonfish Trichiurus lepturus in coastal waters of south-western Taiwan

摘要

The catch of ribbonfish Trichiurus lepturus in the coastal waters of south-western Taiwan has significantly declined in recent years. To examine the effects of exploitation on the feeding habits of ribbonfish, 1570 specimens were collected on a monthly basis during March 2002-March 2003 from the landings by trawlers operating in the coastal waters of south-western Taiwan. The size of the ribbonfish ranged from 83–298 mm, preanal length (PL), with a peak at 201–250 mm PL. Although they fed on shrimps and squid, fishes including Benthosema pterotum, Bregmaceros lanceolatus and Encrasicholina heteroloba were their main food items. In particular, B. pterotum was the most important food all year except during summer No evidence of cannibalism was found in this study. No differences between day and night were found in the feeding activity of T. lepturus. However, B. pterotum and Acetes intermedius were the most important prey in the daytime, whereas B. lanceolatus, B. pterotum and E. heteroloba were at night. Feeding activity and the number of food items increased with increasing size of ribbonfish. Their feeding intensity in February to June, the main spawning season, was significantly greater than in other months. Changes in the food and feeding habits of this species before and after the recent period of heavy exploitation are discussed in detail in this study.