Trophic levels and feeding characters of marine fishes in the Yellow Sea and northern East China Sea based on stable isotope analysis

Abstract:

This study analyzed the carbon and nitrogen stable isotopes from 36 species of marine fishes in the Yellow Sea and northern East China Sea in 2011~2014. The feeding characters were determined by calculating the benthos proportion (Bp) with the δ13C data, and the trophic levels (TLs) were calculated using the δ15N data. The results showed that the trophic levels of the fishes ranged from 2.75 to 4.34 (mean 3.47). Four of the 36 species were completely plankton-feeding, and eight of them were benthos-feeding. The number of mixed feeding and complete benthos-feeding species was 12. Most of the fish species (91.67%) belonged to the middle (TL=3.5~4) and low (TL<3.5) trophic levels. However, the number of high trophic level (TL>4) species was only 3, and all were mixed feeding. In contrast to the TL research results of 1986, 1992, and 2004, the authors of this paper found that the trophic levels of some species had changed slightly in recent years. For example, the TL of Scomberomorus niphonius had decreased to varying degrees, while that of Setipinna taty had increased to a certain extent. The feeding character results were compared to those of 2004, 2009, and 2011. It showed that the feeding character of some fishes, such as Argyrosomus argentatus, had changed significantly. That of others, such as Larimichthys polyactis, had not changed significantly.