Marine ranching, which is considered a sustainable fishery mode that has advantages for the ecosystem approach to fishery, the ecosystem approach to aquaculture, and capture-based aquaculture, is rapidly growing in China. The development of marine ranching requires integrating different theoretical frameworks, methodological approaches for conceptual exploring, and models and management of ecosystem frameworks. We reviewed the definition of marine ranching, the history of marine ranching construction in China, and the techniques, principles, and cases of marine ranching construction and management in the East China Sea (ECS). We highlight four major developments in marine ranching in the ECS: (1) marine ranching site selection and design, (2) habitat restoration and construction technologies, (3) stock enhancement and the behavioral control of fishery resources, and (4) marine ranching management. We conclude that this step-wise procedure for marine ranching construction and management could have comprehensive benefits in terms of ecology, the economy, and society. Finally, a synthesis of the existing problems in ECS marine ranching construction, along with future challenges and directions, are outlined.

Intense fishing pressure and climate change are major threats to the fish population and coastal fisheries. Larimichthys crocea (large yellow croaker) is a long‐lived fish, which performs seasonal migrations from its spawning and nursery grounds along the coast of the East China Sea (ECS) to overwintering grounds offshore. This study used length‐based analysis and habitat suitability index (HSI) model to evaluate the current life‐history parameters and overwintering habitat suitability of L. crocea, respectively. We compared recent (2019) and historical (1971–1982) life‐history parameters and overwintering HSI to analyze the fishing pressure and climate change effects on the overall population and overwintering phase of L. crocea. The length‐based analysis indicated serious overfishing of L. crocea, characterized by reduced catch, size truncation, constrained distribution, and advanced maturation causing a recruitment bottleneck. The overwintering HSI modeling results indicated that climate change has led to decreased sea surface temperature during L. crocea overwintering phase over the last half‐century, which in turn led to area decrease and an offshore‐oriented shifting of optimal overwintering habitat of L. crocea. The fishing‐caused size truncation may have constrained the migratory ability, and distribution of L. crocea subsequently led to the mismatch of the optimal overwintering habitat against climate change background, namely habitat bottleneck. Hence, while heavy fishing was the major cause of L. crocea collapse, climate‐induced overwintering habitat suitability may have intensified the fishery collapse of L. crocea population. It is important for management to consider both overfishing and climate change issues when developing stock enhancement activities and policy regulations, particularly for migratory long‐lived fish that share a similar life history to L. crocea. Combined with China's current restocking and stock enhancement initiatives, we propose recommendations for the future restocking of L. crocea in China.

Stable isotope analyses of food webs have been used in previous decades to determine trophic sources and food web structures. The use of stable isotope models to estimate consumption contributions is based on a type of multivariate beta distribution called the Dirichlet distribution. The Dirichlet distribution does not conclude the p_i = 0 and p_i = 1 situation. Thus, scientists have previously assumed that every potential trophic source contributes to consumption in stable isotope models. However, animals have dietary preferences and some trophic resources may not contribute to consumption. Less is known about the effects of species-specific dietary processes on stable isotope analyses, especially in regard to trophic contribution estimation. In this study, we develop methods to determine consumers’ “real potential trophic sources” and “discrimination factors” using lab-based observations and lab-based discrimination experiments. We describe a dietary process-based stable isotope mixing model (D-SIMM) that integrates lab-based dietary preference observations and the stable isotope mixing model (SIMM) to estimate trophic contributions. Then, we present the application of D-SIMM on three representative macroinvertebrate species in our study area (sea urchin: Anthocidaris crassispina (A. crassispina); gastropod: Turbo cornutus (T. cornutus); and mussel: Septifer virgatus (S. virgatus)) to re-evaluate source-consumer contributions. Thus, we compare the differences between the source contribution estimation results of SIMM and D-SIMM by calculating the standardized convex hull area (TA) of species-specific trophic sources and the consumer standard ellipses area (SEA) of the potential trophic source group. Three examples illustrate significant differences in species-specific dietary preferences between consumers, resulting in systematic difference for TA, SEA and trophic source contribution estimation results between SIMM and D-SIMM. As such, D-SIMM explains p_i = 0 of certain trophic sources, which often causes uncertainty and is ignored in previous SIMM research. In addition, species-specific discrimination factors should be noticed during trophic source estimation. For estimation of the trophic contribution of source-consumers, our findings imply that the dietary preferences of consumers should be fully considered before SIMM analysis, and that D-SIMM is a more ecological process and robust measure. Additionally, we found high macroalgae (MAC) coverage in seaweed beds and a high detritus contribution of MAC to sedimentary organic matter (SOM). These findings, combined with the high contributions of MAC and SOM to consumers, suggest that MAC and its debris are the basal trophic sources for gastropods, sea urchins and mussels in seaweed bed habitats. The conservation of seaweed beds should be fully considered to ensure sustainable utilization of shellfish.