Domestication strategies for the endangered catfish species Pseudopimelodus mangurus Valenciennes, 1835 (Siluriformes: Pseudopimelodidae)

Abstract Wild fish domestication can be considered a strategic approach to endangered species conservation, supporting studies and reducing economic and environmental costs. Three of the most important strategies in the domestication processes of fish are the adaptation of wild fish to captivity, the reproduction of the adapted fish and the production and maintenance of the young individuals. That being said, the present study is divided in three experiments: the 1st aimed to adapt wild Pseudopimelodus mangurus to captivity environment using different feeding approaches and a prophylactic strategie; the 2nd aimed to reproduce the adapted individuals from the 1st experiment; and the 3rd aimed to train the P. mangurus juveniles to accept commercial diets. The 1st and 2nd experiments were successful at the maintenance and artificial reproduction of P. mangurus kept in tanks between the reproductive seasons. The results suggest that the reproductive performance of animals kept in captivity (initial relative fertility-IRF = 609.25 ± 36.6 eggs/g) was similar (p > 0,05) to the performance found in wild individuals (IRF = 679.21 ± 45.66 eggs/g). Feed training of P. mangurus juveniles (3rd experiment) was also conducted, evaluating three feeding treatments with different concentrations of bovine heart and ration. At the end of the experiment, the treatment containing half bovine heart and half commercial feeding resulted in the highest values of weight gain (0.10 ± 0.16 g), specific growth rate (0.37 ± 0.11 mm), length (47.78 ± 2.35 mm) and growth (2.15 ± 2.27 mm), suggesting reasonable acceptability to artificial diets in the cultivation of this species. As conclusion, the present study contributes with the development of techniques for the domestication of fresh water fish species with commercial value or andangered of extinction, showing the domestication and reproduction of wild P. mangurus in captivity. However, more studies have to be conducted in order to improve the acceptance of artificial feeding by juveniles and to increase their survival rate.

摘要 野生鱼类驯化可作为濒危物种保护的战略手段，可为相关研究提供支撑并降低经济与环境成本。鱼类驯化流程中的三大核心策略依次为：野生鱼类对人工养殖环境的适应性驯化、驯化个体的人工繁殖，以及幼体的培育与维持。据此，本研究设置三项实验：第一项实验通过不同投喂方案与预防性养殖策略，将野生Pseudopimelodus mangurus（以下简称P. mangurus）适配至人工养殖环境；第二项实验旨在对第一项实验中完成驯化的个体开展人工繁殖；第三项实验则针对P. mangurus幼体开展投喂驯化，使其接受商用配合饲料。

第一项与第二项实验均成功实现了繁殖季内养殖缸饲养的P. mangurus的保种与人工繁殖。研究结果显示，人工饲养个体的繁殖性能[初始相对繁殖力（initial relative fertility, IRF）=609.25±36.6粒卵/克]与野生个体（IRF=679.21±45.66粒卵/克）无显著统计学差异（p>0.05）。第三项实验针对P. mangurus幼体开展投喂驯化，设置了三种含有不同比例牛心与商用配合饲料的投喂处理组。实验结束后，投喂"半牛心半商用配合饲料"的处理组，其幼体的增重（0.10±0.16克）、特定生长率（0.37±0.11 mm）、体长（47.78±2.35毫米）与生长增量（2.15±2.27毫米）均为最高，表明该幼体对人工配合饲料具备较好的接受度，可用于该物种的养殖实践。

综上，本研究为具备经济价值或濒危的淡水鱼类驯化技术开发提供了实践参考，成功实现了野生P. mangurus的人工驯化与繁殖。不过仍需开展更多研究，以进一步提升幼体对人工饲料的接受度与成活率。