Diet analysis for fishes based on DNA barcoding：a case study on grenadiers (Coelorinchus spp.) from Taiwan.

• Main Authors: Sz-Chuen Wang, 王思淳
• Other Authors: Kwang-Tsao Shao
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/03832256942765747477

碩士 === 國立臺灣海洋大學 === 海洋生物研究所 === 98 === The grenadier is the most dominant fish species of the demersal fish community in the waters of northeastern Taiwan. Due to their relatively larger size, higher abundance and with more various species, they are the major predator in the local demersal community. However, since the notorious bottom trawler fishing gear is still popular in Taiwan, the less economically valuable grenadiers are forced to face the by-catch problem seriously. In order to maintain the sustainable use of the marine resources in the Taiwan water, it is essential to study the biology and ecology of the grenadiers, one of the major predators in deep sea, especially it’s food habit. These data should be important to do better resources management by ecosystem approach. In recent years, the barcode of life is becoming a widely adopted tool such as using mtDNA COI (cytochrome c oxidase I) sequences for basic taxanomy and ecological studies and applicable to ecology. In the past, morphology of the remains of the stomach-content was the primary means used to determine the fish diet, however it was limited to coarse taxonomic resolutions and the accuracy was often not very high. Hence the aim of this thesis is try to find out the species or taxa name of the gut content found in the stomach, for the two dominant species of grenadiers in northeastern Taiwan: Coelorinchus kishinouyei and C. leptorhinus. The other goats of this thesis include: 1)the differences between molecule technique and morphological method to identify the gut contents; 2) the advantages and disadvantages of the barcode technique, when applying it on the identification of fish gut contents. A tatal number of 197 samples of stomach-content were collected from the remains found in 13 grenadiers. 130 sequences were successfully amplified from these samples, which belongs to 61 haplotypes. Among them, there are four species could be accurately identified, ther are: Plagusia immaculate, Heterocarpus sibogae, Chiridius armatus and Calanus sinicus. In those 61 haplotypes, one could be identified as the Ophichthidae by construct NJ tree. Other species including 23 Amphipoda, 15 Polychaeta, 11 Decapoda and 11 Copepoda. Our research results also show that the most frequently found species of the preys are Polychaeta and Amphipoda. Because many food items identified by traditional morphological still contain many species or genetic varieties, if the database is complete and accurate, the genetic sequences of these preys found in the stomach of grenadiers can be identified exactly. We also demonstrate that it is possible to obtain the genetic sequences from the remains of the gut content of demersal fish, and it can effectively solve the problem of not being able to identify the remains of the stomach content that often happen with the traditional method, even the remains appear in a heavily scattered shape, or lost its appearance after being digested by the stomach acid. Now a day, one can almost always identify the exact species with the help of the modern sophisticated molecule tools. Unfortunately, due to the incomplete of the database, there are still some problems and difficulties to be overcome. Hence this thesis suggests that to establish one complete database of the barcode in marine life is very important to do this kindy ecological studies.