Design of a multi-parametric profile for assessing the acclimation period of juvenile brown trout after an acute transport to new housing environment

Laboratory Studies on the Rheotaxis of Fish under Different Attraction Flow Conditions

The damming of the river changes the structure of the original river ecosystem, and although fish passage plays an important role in maintaining the connectivity of the river ecosystem, the fish have difficulty finding the fish passage entrance during the upstream process. This paper studied the rheotaxis of fish under three different water flow conditions experimentally through recirculating water tanks. To better understand the response of Crucian carp (Carassius auratus) to water flow stimulation, the representative swimming trajectory, sensing success rate, attraction success rate, reaction time, and attraction time of the fish were analyzed by using a video monitoring system. The experimental results showed that fish responded differently to single-peak and lateral bimodal outflow conditions: (1) the single-peak outflow condition had a much better attraction effect than the lateral bimodal outflow condition, both in terms of sensing success rate and attraction success rate; (2) the fish swam mainly in the middle area of the lateral bimodal outflow condition, while the fish swam more evenly in the single-peak outflow condition. Therefore, setting the attraction current at the right time and near the entrance of the fish passage may help to improve the effect of fish attraction.

Knowledge of, and Attitudes towards, Live Fish Transport among Aquaculture Industry Stakeholders in China: A Qualitative Study

Simple Summary

China is the world’s largest producer of food fish, and Chinese consumers have a preference to buy live fish. Live transport of fish is, therefore, a common procedure in aquaculture and is a potential animal welfare hazard. Little has been published on current fish transportation practices in China or the knowledge and attitudes of stakeholders in this industry. Our qualitative study aimed to obtain original information about live transport processes from a cross-section of aquaculture stakeholders in China by conducting individual interviews. Stakeholders were interviewed about their knowledge of live transport and their attitudes towards the welfare of fish. Self-described knowledge of live transport varied between participants with different job types. Most participants had heard of and understood the concept of “animal welfare”, but many understood it to only refer to terrestrial livestock, not fish. This suggests that knowledge of fish welfare in the industry may be less than for other farm animals. The findings of this pilot study contribute to a better understanding of live fish transport from a stakeholder point of view. The findings will also assist in informing, educating, and sensitizing stakeholders to the importance of fish welfare during live transport.

Abstract

China is the largest food fish producer in the world. Chinese consumers normally purchase fish that are still alive to ensure freshness. Therefore, the live transport of fish is important in China’s aquaculture, although it carries potential risks for animal welfare. This study investigated the attitudes and knowledge of stakeholders within Chinese aquaculture towards the live transport and welfare of fish. Semi-structured interviews were conducted with 12 participants who were involved with the aquaculture industry in China. Most participants self-rated their transport-related knowledge as moderate and had some understanding of animal welfare, although this term was generally considered only relevant to terrestrial animals. Participants’ responses indicated that the live transport of fish occurs frequently in China, generally using sealed tanks, plastic bags, and foam boxes, in purpose-built vehicles. Seasonal changes, such as changes in ambient and water temperature, are considered to be important contributors to successful live transport, as well as sufficient oxygen supplies and stocking density. The use of anesthetics was not commonly reported, particularly in food fish, and fish capture is predominantly by conventional dipnets. The health status of transported fish is determined mostly by morphology (body injury, body or eye color, and fin condition), as well as vigor and swimming ability. Our results indicate that live transport poses a number of welfare risks to fish but that participants in the process associated welfare concerns more with terrestrial animals, not fish.