Fatty acid composition and feeding habits analysis of the main catches from Lüsi fishing ground during spring, summer and autumn

Abstract:

In order to explore the nutritional value, feeding habits and seasonal changes in the main catches from Lüsi fishing ground, we measured fatty acid composition of the main catches collected through a fishery resources survey in May 2018, August 2018, and October 2018. We analyzed feeding habits based on fatty acid biomarkers. The results of the eight main catches showed that the value for PUFA/SFA was 0.88~1.79 and that for n-3/n-6 was 2.56~3.18. C16:1n7, Σ15+Σ17 increased significantly in summer (P<0.05). The EPA+DHA, PUFA/SFA, n-3/n-6, C20:4n6, C22:6n3, and Σ22+Σ24 increased and C20:1+C22:1 decreased significantly in autumn (P<0.05). Previous studies have shown that the nutritional value of each catch is high and was significantly higher in autumn than in spring and summer. The nutritional value of Collichthys lucidus and Larimichthys polyactis was the highest. DHA/EPA and cluster analysis divided the catches into three groups: Parapenaeopsis hardwickii, Metapenaeus joyneri and Charybdis japonica; Coilia mystus, Johnius belangerii, C. lucidus and L. polyactis; Pampus argenteus. P. hardwickii, M. joyneri and C. japonica preferred phytoplankton and benthos. L. polyactis and C. mystus preferred zooplankton. P. argenteus preferred phytoplankton and zooplankton. C. lucidus and J. belangerii had no obvious preferences. In general, food source on diatoms and bacteria increased significantly in summer. In autumn, food source significantly increased on benthos, dinoflagellates, and terrestrial plants and it decreased on zooplankton.