蕭仁傑老師研究焦點

研究主題一：深海魚類的洄游生活史

我們對於深海魚類耳石的微結構和穩定性同位素進行分析，以了解深海魚類個體發育時的垂直遷移模式。分析結果顯示，不同魚種有不同的垂直遷移方式(例如遷移時間與距離的變異)。Jen Chieh Shiao

Research topic 1 – Migratory life history of deep sea fishes

We analyzed otolith microstructures and stable isotope of deep sea fishes to reveal their ontogenetic vertical (downward) migration. Otolith microstructures and δ18O showed different migratory patterns, e.g., migration timing and distances, among species.

conceptual-diagram — Fig. 1. A conceptual diagram showing different patterns of vertical downward migration for grenadier larvae and juveniles. The larvae may metamorphose during sinking, or they may metamorphose after settlingt on the sea floor. The migrating distances vary among the species.

http://www.sciencedirect.com/science/article/pii/S0967063711002378

Research topic 2 –Eutrophication reduce diversity of demersal fish in East China Sea.

Through oceanographic surveys for several years, we find that the inshore area of the East China Sea, corresponding to the prohibited zone for trawling, had extremely high nutrient concentrations and low dissolved oxygen. The diversity index of demersal fish showed significantly negative correlations with nutrient concentrations and positive correlations with bottom-water dissolved oxygen. The inshore area of the East China Sea was heavily dominated by small-sized fishes, reflecting low survival of most fish species. These findings suggest that eutrophication and subsequent hypoxia could have limited fish population growth in the trawling prohibition area of the East China Sea despite of absence of fishery operations. Therefore, a multi-pronged fishery management plan that involves both fishing restriction and environmental improvement is urgently needed in the East China Sea.

jay — (圖一) 長尾鱈科仔魚及幼年魚的垂直向下遷移模式的概念圖。仔魚可能在沉降時或到達海底時變態，並且物種之間會有不同的遷移距離。

http://www.sciencedirect.com/science/article/pii/S0967063711002378

研究主題二：東海優養化降低底棲魚類的多樣性

透過幾年來在東海海域的調查，我們發現在實施禁止拖網的近岸處有極高的營養鹽濃度以及極低的溶氧濃度。底棲魚群的多樣性指標與營養鹽濃度呈負相關趨勢，與底層水的溶氧濃度則呈現正相關趨勢。在東海近岸海域捕獲的大多數魚體長偏小，在此顯示出個體存活率低。這些發現說明優養化造成之低氧環境限制東海近岸海域的漁業資源恢復力，因此在東海海域多重的漁業管理策略，包括捕撈的限制以及環境的改善都是必要考慮的地方。