Stomach content analysis of Etrumeus micropus in the coastal waters of Penghu off Taiwan in late summer

Abstract

In this study, we investigated the feeding ecology of Etrumeus micropus, which is a major commercial fishing and coastal fish species in Penghu during late summer. We collected a total of 93 samples from the coastal waters of Shuchiaoyu, Penghu, between August 2015 and October 2015. The fork length and body wet weight of samples ranged from 107.88 to 172.17 mm and from 12.13 to 75.93 g, respectively. Regarding the degree of stomach filling, the percentage of empty stomachs decreased and that of full stomachs increased with an increase in body length over time. The dominant prey categories found were fish, Mysidacea, and crab zoea (index of relative importance = 6512, 4542, and 1086, respectively). The feed of E. micropus changed over time, not with the body size. The index of relative importance of Mysidacea in the diet of E. micropus over 3 months increased with time, indicating their importance as prey for E. micropus. Regarding biological diversity, the distribution of feed types was more uniform when the body size was large but did not exhibit any correlations with body size or date.