Seagrass beds at night as a feeding ground for fish

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K22586
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0603:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: Kagoshima University
• Principal Investigator: Kodama Masafumi 鹿児島大学, 農水産獣医学域水産学系, 助教 (30883269)
• Project Period (FY): 2020-09-11 – 2022-03-31
• Keywords: 藻場 / アマモ / 魚類 / 葉上動物 / 捕食-被食

Outline of Final Research Achievements

The study examined whether the function of seagrass beds as feeding grounds for fishes differs during the day and night, being conducted in Yojiro, Kagoshima. The potential prey assemblage structure in the study site did not change significantly between day and night in the sediment or on leaves, whereas it changed between day and night in the upper water column. Some small dominant fish species utilized the seagrass beds throughout day and night, while some larger fish species migrated to the seagrass beds only during night and engaged in feeding activities. The composition of the gut contents of the fish species that dominated throughout day and night did not change significantly between day and night. Whether the function as a feeding ground differs between day and night depends on the ecology of the fish species, which can be broadly divided into two groups: fishes that use the seagrass beds as a feeding ground both day and night, and those that only use it only at night.

Free Research Field

海洋生態学

Academic Significance and Societal Importance of the Research Achievements

藻場には多様な無脊椎動物が高密度で生息するとともに、それらを餌料として様々な魚類も多く分布している。摂餌場の提供は、魚類生産に直結する藻場の重要な機能の一つであり、藻場の持続的利用や適切な管理・保全のためには、魚類やその餌生物を中心とした藻場の生物生産構造を正しく理解することが必要となる。
藻場の魚類や餌生物を扱った既往研究の大部分は日中に行われてきたが、実際には、夜行性の種も数多く存在することから、藻場生態系の様相は昼夜で全く異なる可能性が高い。一日のうちおよそ半分の時間は「夜間」であるため、魚類の摂餌場としての藻場の機能を正しく理解するには、日中だけでなく夜間における知見も不可欠である。