Comparison of the stomach contents of juvenile chum salmon (Oncorhynchus keta), based on morphological observations and DNA-based analyses

Representative Organization: Japan Agency for Marine-Earth Science and Technology

2013/05/23 - 2013/06/05

offshore of Sanriku

Research Cruise

We compared the prey richness of juvenile fishes using morphological observations and DNA-based analyses, with a focus on juvenile chum salmon Oncorhynchus keta.

We compared the prey richness of juvenile fishes using morphological observations and DNA-based analyses, with a focus on juvenile chum salmon Oncorhynchus keta. A higher number of prey taxa were successfully identified using DNA-based analyses than morphological observations. However, we also noticed several shortcomings of the DNA-based analyses, as reported in other diet-analysis studies that used molecular techniques. For example, the degree of digestion among prey taxa might have resulted in differential sensitivity to DNA detection. Additionally, several prey taxa could not be precisely identified, as the sequence data for some of the targeted organismal groups is unavailable in public gene databases. Remarkably, it is also possible that DNA-based analyses detected secondary prey, and therefore, the richness of prey taxa was likely overestimated. Thus, dietary analyses of juvenile fishes need to be carefully conducted, considering the respective advantages and disadvantages of DNA-based and morphological techniques.

FY2015 Comparison of the stomach contents of juvenile chum salmon (Oncorhynchus keta), based on morphological observations and DNA-based analyses

Sequences of the mitochondrial gene COI