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The Danjiangkou Reservoir is the water source of the middle route of China’s South-to-North Water Diversion Project, encompassing the Dan Reservoir and Han Reservoir. However, little is known about the ecological functions of this important ecosystem. Based on a survey conducted in 2023 in the Dan Reservoir, a mass balance model was constructed usi...
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... entering the primary parameters into the Ecopath model and conducting a thorough balancing and debugging process, the outcomes for the Dan Reservoir were methodically generated (Table 3). The food web within the Dan Reservoir demonstrated a spectrum of effective trophic levels, extending from 1 to 3.50. ...Similar publications
The aim of this paper is to develop a methodology to estimate recovery times using a wide range of published Ecopath modeled overfished data-rich fisheries that had not recovered in the North Sea, Mediterranean, and South America shelves. Recovery times were estimated by biomass increase according to the Verhulst logistic equation mathematical solu...
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... t/(km 2 ·year), total production of 22,753.85 t/(km 2 ·year), and a mean trophic level of the catch at 2.50 [28]. The connectivity index stands at 0.25, the system omnivory index at 0.23, and Finn's cycling index at 24.61%. ...
The Geheyan Reservoir, located on the Qingjiang River, a tributary of the Yangtze River, is important for regional water supplies and ecological conservation. Understanding changes in ecosystem structure and function has become critical for assessing efficacy after the implementation of a fishing ban. This study employs the Ecopath model to examine the ecosystem characteristics of the Geheyan Reservoir before (2017) and after (2022) the fishing ban. The results show significant differences in trophic levels, energy transfer efficiency, and ecosystem maturity between the two periods. The trophic levels increased from 3.36 pre-fishing ban to 3.89 post-ban, indicating an enhanced complexity in the food web structure. The highest eco-trophic efficiency for major commercial fish species increased after the ban, indicating improved energy utilization efficiency. However, energy transfer bottlenecks were still observed between trophic levels II and IV, suggesting ongoing challenges in nutrient cycling. The total primary production-to-total respiration ratio (6.93) and the connectivity index (0.25) indicate that the ecosystem’s maturity and stability have improved after the fishing ban. These findings underscore the ban’s effectiveness and provide a scientific foundation for sustainable management of Geheyan Reservoir and similar ecosystems in the Yangtze River Basin.
... In contrast, the "carbon content" method estimates only 25.47% of this value, resulting in significantly different conclusions. The disparities between these methods stem from various factors, including the average transfer efficiency among organisms at different energy flows, the trophic levels of distinct aquatic species [29,30], and their carbon metabolism [31,32]. ...
... Consequently, freshwater fisheries serve dual roles as both carbon sinks and carbon sources. Therefore, by examining the carbon balance [30,43], we must scientifically determine whether freshwater fisheries act primarily as carbon sinks or sources, or exhibit dynamic characteristics. Furthermore, it is essential to integrate this with existing freshwater fishing yield databases, adopt carbon sink accounting methods, develop a national database for freshwater fishing carbon sinks, and perform carbon sink analyses based on the development of ecosystems over time, regional distribution of fisheries, and species composition. ...
Optimizing biological carbon sequestration has become a primary strategy in global low-carbon-emission initiatives. Freshwater fisheries in reservoirs play an important role in aquatic biological carbon sequestration. However, a standard method for evaluating the carbon sink capacity of inland fisheries has not been developed. Therefore, this study aimed to assess and compare the carbon sequestration potential of the Qianxiahu Reservoir’s fisheries using the trophic level and mass-balance methodologies. The Ecopath model was employed to determine the trophic levels of aquatic organisms within the Qianxiahu Reservoir ecosystem, with input parameters sourced from in situ surveys and the literature on reservoirs. The model includes 21 functional groups, with trophic levels ranging from 1.000 to 3.281. The key species identified are silver carp, bighead carp, and crucian carp. The indices of Finn’s cycling index (FCI), connectivity index (CI), system omnivory index (SOI), and total primary production/total respiration (TPP/TR) for the Qianxiahu Reservoir are 11.35, 0.27, 0.196, and 1.540, respectively. These values indicate a high degree of material recycling and complex interconnections among functional groups. The fishery carbon sink potential of the Qianxiahu Reservoir, calculated using the trophic level and carbon content methods, yielded values of 261.8362 tons/km² and 66.6818 tons/km², respectively. The trophic level method showed a notable increase of 195,1544 tons/km² compared to the carbon content method, underscoring significant differences in results between the two methods. The study concludes with recommendations for research on methods to assess the carbon sink capacity of freshwater fisheries, aiming to establish a scientific framework for this evaluation.
