11:00 〜 13:00
[AOS12-P07] Detection of fish community distribution by MiFish analysis and comparison of typical fish community assemblage with ocean frontal structure
キーワード：Environmental DNA (eDNA), MiFish Analysis, Kuroshio, Fish Community Assemblage, Cluster Analysis
Environmental DNA (eDNA) is gaining immense popularity in understanding fish species distribution pattern and biodiversity monitoring in the ocean due to its non-invasive nature and convenience to use. The eDNA is derived from the genetic materials present in water and gleaned from various sources including skin cells, feces and mucous. MiFish metabarcoding technique is a modern technique in analyzing fish community distribution in larger waterbodies which capacitates detection of huge number of species at a short time provided with some precautions in sampling.
This study focuses on the distribution of fish species along the Kuroshio and Kuroshio Extension front of the North Pacific and aspires to understand the effects of frontal structure on the fish community structure from the collected samples of two research vessels (Shinsei-maru KS-18-5 in May 2018 and Hakuhomaru KH-20-9 in September-October 2020) at different vertical lines (0 to 300m) with a view of the fish species richness and comprehending spatial variations. The samples were collected, filtered, and stored appropriately to extract the DNA and finally segregated in respective Operational Taxonomic Units (OTUs) by MiFish analysis.
A total of 269 species has been detected and they are assigned to their respective ratios. The samples were subjected to cluster analysis based on species composition using complete method with Bray Curtis distance. Eventually, the samples have been cleaved into 8 (eight) clusters where cluster 4, cluster 3 and cluster 5 are the most dominant in space. All the clusters are extremely diversified, except for cluster 7 and cluster 8 which are mainly consisted of several non-commercial small species of ray-finned fishes and lantern fishes. The dominant clusters are dominated by one or two species accompanied by several non-dominant species indicating a highly diversified environment of the surrounding ecosystem. The principal species of the most dominant clusters (cluster 4, cluster 3 and cluster 5) are Sardinops melanostictus, Encrasicholina punctifer, and Diaphus theta which account for 43%, 29% and 39% respectively. The cluster 1, cluster 2 and cluster 6 are basically dominated by few species of mesopelagic fishes which are not economically significant but are critical in playing ecological role such as linking pelagic and mesopelagic food web. Some of the clusters distributed at a specific depth. In addition, several clusters showed close link to the Kuroshio frontal structure and are mainly distributed either in downstream or upstream. The study promulgates the feasibilities of using MiFish analysis for biodiversity study and creates passage of concocting the influence of frontal structure on fish assemblage.
This study focuses on the distribution of fish species along the Kuroshio and Kuroshio Extension front of the North Pacific and aspires to understand the effects of frontal structure on the fish community structure from the collected samples of two research vessels (Shinsei-maru KS-18-5 in May 2018 and Hakuhomaru KH-20-9 in September-October 2020) at different vertical lines (0 to 300m) with a view of the fish species richness and comprehending spatial variations. The samples were collected, filtered, and stored appropriately to extract the DNA and finally segregated in respective Operational Taxonomic Units (OTUs) by MiFish analysis.
A total of 269 species has been detected and they are assigned to their respective ratios. The samples were subjected to cluster analysis based on species composition using complete method with Bray Curtis distance. Eventually, the samples have been cleaved into 8 (eight) clusters where cluster 4, cluster 3 and cluster 5 are the most dominant in space. All the clusters are extremely diversified, except for cluster 7 and cluster 8 which are mainly consisted of several non-commercial small species of ray-finned fishes and lantern fishes. The dominant clusters are dominated by one or two species accompanied by several non-dominant species indicating a highly diversified environment of the surrounding ecosystem. The principal species of the most dominant clusters (cluster 4, cluster 3 and cluster 5) are Sardinops melanostictus, Encrasicholina punctifer, and Diaphus theta which account for 43%, 29% and 39% respectively. The cluster 1, cluster 2 and cluster 6 are basically dominated by few species of mesopelagic fishes which are not economically significant but are critical in playing ecological role such as linking pelagic and mesopelagic food web. Some of the clusters distributed at a specific depth. In addition, several clusters showed close link to the Kuroshio frontal structure and are mainly distributed either in downstream or upstream. The study promulgates the feasibilities of using MiFish analysis for biodiversity study and creates passage of concocting the influence of frontal structure on fish assemblage.