# Life-History Plasticity of Cultured Coreius guichenoti: Energy Allocation Trade-Offs and Conservation Applications

## TL;DR

This study shows how captive conditions change the life cycle of Coreius guichenoti, offering insights for better conservation strategies.

## Contribution

The study reveals rapid life-history plasticity in C. guichenoti under captive conditions, useful for conservation planning.

## Key findings

- Cultured fish grow faster, mature earlier, and produce more eggs compared to wild fish.
- Cultured C. guichenoti exhibit an opportunistic life strategy, while wild fish show a periodic strategy.
- The species can shift energy allocation within a single generation, aiding conservation efforts.

## Abstract

This study examines how captive conditions affect the life-history traits of Coreius guichenoti. Fish kept at constant warm temperatures with abundant food tended to grow faster, mature earlier, and produce more and larger eggs than wild fish. The cultured group thus appeared to lean toward an opportunistic strategy focused on rapid reproduction, whereas the wild group tended toward a periodic strategy that balances long life with timed spawning. These cultured traits appear within one generation, showing that the species can flexibly shift energy allocation within a single generation. These findings provide a scientific basis for selecting broodstock and conducting short-term wild acclimatization prior to release, thereby supporting the restoration of this endangered species in the Yangtze River.

Coreius guichenoti, an endemic fish of the upper Yangtze River, has experienced severe population decline due to overfishing and habitat fragmentation. To inform its conservation, this study compared life-history traits between artificially bred and historical wild populations, revealing pronounced plasticity in response to environmental conditions. The cultured population, dominated by age 0–4 individuals but retaining a notable proportion of age 5–6 fish, exhibited faster growth and higher fecundity (mean absolute fecundity 32,724 ± 24,132 eggs; relative fecundity 37.5 ± 18.5 eggs/g) than the wild population. In contrast, the wild group consisted of >90% age 0–4 individuals, showed virtually no fish aged 5–7, reproduced seasonally with high total egg output, and tended toward a periodic life-history strategy, whereas the cultured group tended toward an opportunistic strategy that still retained some periodic traits. These results demonstrate that C. guichenoti can adjust its life history on a within-generation scale. Accordingly, we recommend pre-release conditioning with moderate flow and temperature variations to enhance field adaptability. This study provides evidence-based guidance for broodstock selection and preconditioning in restocking programs, aimed at improving post-release survival and reproductive success in the wild.