Analysis of finless porpoise diet using prey morphological characters and DNA barcoding
Zhichuang Lu1,2, Shengyong Xu1, Jiabo Han2 and Tianxiang Gao1
1Ocean
University of China, Qingdao, PR China. E-mail: gaotianxiang0611@163.com
Ocean and Fisheries Science Research Institute, Dalian, PR China
2Liaoning
Knowledge of the dietary choices and trophic niches of organisms is the key to understanding
their roles in ecosystems. DNA-based techniques have proven useful for defining trophic links in a
variety of ecosystems and recently developed sequencing technologies provide new opportunities
for dietary studies. We investigated the diet of finless porpoise (Neophocaena asiaeorientalis
sunameri) at several colonies across its range, based on a total of 23 prey samples collected from
dead finless porpoises killed by ship, bycatch or stranding. The diet was assessed using two
complementary approaches for prey identification: conventional morphological analysis (using
fish vertebrae, otoliths and cephalopod beaks) and DNA barcoding of COI (using fish) and 16S
(using cephalopods) mitochondrial genes. Species assignments employed BLAST and
distance-based methods. The molecular approach increased taxonomic resolution and revealed an
additional 9 taxa. Most of the prey species were identified for the first time. The DNA barcoding
approach significantly presented the capabilities of DNA-based methods of dietary analysis. More
prey samples collected by non-lethal methods are needed to shed light on this species’ diet, trophic
niche, and roles in the marine ecosystem. Results facilitate more suitable protective measures to be
taken to conserve the finless porpoise.