基于碳、氮稳定同位素研究黄海及东海北部主要鱼类的营养级和食性

本研究通过对2011~2014年间在黄海及东海北部采集的36种海洋鱼类进行碳、氮稳定同位素测定,利用碳稳定同位素比值(δ¹³C)计算底层饵料贡献比(Bp)来确定鱼类的食性,利用氮稳定同位素比值(δ¹⁵N)计算其营养级(TL)。结果显示,这36种鱼类的营养级范围为2.75~4.34,平均值为3.47。其中,4种为完全浮游生物食性,8种为底栖生物食性,完全底栖生物食性为12种,混合食性为12种。中(TL=3.5~4)、低(TL<3.5)营养级的种类占大多数(91.67%),而高营养级(TL>4)种类较少,仅为3种,且全部为混合食性。营养级的研究结果与1986、1992和2004年的研究对比发现,个别种类发生了改变。如蓝点马鲛(Sconberonorus niphonius)营养级有不同程度的下降;而黄鲫(Setipinna t)aty却有不同程度的上升。食性的研究结果与2004、2009和2011年的研究对比发现,有些种类食性发生了较大变化,如白姑鱼(Argyrosomus argentatus);有些种类食性几乎没有变化,如小黄鱼(Larimichthys polyactis)。

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

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.