Ecological Insights from A Fish Market: Integrating Visual Surveys and eDNA Analyses for Holistic Fisheries Management (by Taner Yildiz)

by Taner Yildiz, Faculty of Aquatic Sciences at Istanbul University in Istanbul, Turkey and 2024 eDNA Collaborative Microgrant recipient

Embarking on a scientific exploration within the confines of Gürpınar Fish market, Turkey's biggest fish market, our research strives to elucidate the intricacies through a multidimensional lens. Beyond the routine confines of traditional fisheries management, our work tries to integrate monthly visual surveys with advanced environmental DNA (eDNA) analyses, forging a comprehensive understanding of the fishery's dynamics.

Our dual methodology includes meticulous visual surveys conducted twice a month, capturing real-time snapshots of the fishery's species composition. The data amassed from these surveys contribute significantly to our ongoing efforts in delineating species composition and temporal variations within these pivotal fisheries.

Figure 1: Gürpınar Fish Market, Turkey's largest fish market with the highest transaction volume, is located in Istanbul.

Simultaneously, we employ cutting-edge eDNA analyses, focusing on water samples extracted from the drainage channels within the auction area. This innovative molecular approach unveils a collective "species footprint," offering insights into the diverse biological material transported through these conduits. By applying eDNA management to water samples with elevated suspended solid density, such as those from the fish market's drainage channels, we aim to ascertain the feasibility of this approach in elucidating species presence.

Figure 2: Sources of biological materials are collected from the drainage channel of the fish market and filtered in the laboratory.

Observing the fishery in action is paramount for effective management. In conjunction with our visual surveys, we meticulously document species lists, providing a real-time perspective on the traded biodiversity. This holistic approach not only contributes to our understanding of the market's dynamics but also serves as a foundation for informed fisheries management strategies.

Figure 3: Some shark species that are completely protected from fisheries have been observed during scientific surveys at fish markets, and we expect to find evidence of their presence through eDNA results.