Feeding efficiency and aggression in juvenile Atlantic salmon, Salmo salar (L.) under alternative feeding regimes

• Main Author: Noble, Christopher
• Format: Thesis
• Language: English
• Published: ProQuest Dissertations & Theses 2001
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://theses.gla.ac.uk/72385/; https://theses.gla.ac.uk/72385/1/10646255.pdf; https://eleanor.lib.gla.ac.uk/record=b2064285

This thesis is a compilation of three long-term studies of on-demand feeding in Atlantic salmon parr and post-smolts in an aquacultural cage environment. The feeding rhythm studies are concerned with whether fish show a daily rhythm of appetite in cage culture. The feeding regime chapters evaluate the effect of an on-demand feeding regime upon growth performance and production when compared with existing fixed ration regimes. Two studies assess the impact of feeding regime upon social interactions around meal times, examining aggression and competition in relation to food presentation. My aim was to show how feeding systems that preferentially distribute feed in relation to changes in appetite could affect fish production and welfare in a cage rearing facility. The AKVAsmart AQ1 adaptive feeding system is the on-demand feeder used throughout this thesis. It is a system that has been designed principally for cage culture and can manage several feeding programs, depending upon farmers' requirements. Chapter 2 reports on the general configuration of the on-demand feeders for each of cage trials in this thesis, outlining the behavioural and production implications of the parameters chosen. Chapter 3 is split into two parts: 3a reports upon the feeding rhythms of Atlantic salmon post- smolts in sea cages; 3b examines the effect of an on-demand feeding regime upon growth performance and social interactions between conspecifics. Chapter 4 is divided into three sections: 4a provides information on feeding rhythms in freshwater production cages under ambient conditions from autumn until spring; 4b evaluates the effects of an on-demand feeding regime on growth performance and production of parr in comparison with an existing fixed ration regime; and 4c examines how a feeding regime can affect the prevalence of fin damage and behavioural interactions between conspecifics around meal times. The final experimental chapter was split into two segments: 5a investigated the feeding rhythms of cage held Atlantic salmon parr in ...