Appetite and Feed Intake

Abstract

This chapter first describes changes in appetite that occur over different time scales in wild fish and the physiological mechanisms that generate these changes. It then gives an account of how food intake and appetite change as young fish develop and mature and the effects of genetic variation and differential experience on these processes. The costs of sustaining a high rate of food intake are then described, as is the way in which these are balanced against the obvious benefits of gaining a good supply of nutrients. The benefits gained by regular appetite cycles are also considered. The implications of natural appetite patterns for fish culture are then discussed, including problems arising from underfeeding and overfeeding and those resulting from failure to match feed delivery to current appetite. Underfeeding causes slow, uneven growth and high levels of aggression, as well as stress and mortality, while overfeeding may result in inefficient production and adverse environmental impact. Potential solutions to such problems are discussed, including the use of on-demand feeding systems that match delivery to appetite. The effects of domestication and captive rearing on feed intake are then considered, together with possible ways of mitigating such effects in fish that are cultured for release.

Towards more efficient longline fisheries: fish feeding behaviour, bait characteristics and development of alternative baits

“…maturation . Changes in feeding motivation can also be rhythmically adapted to daily, tidal or annual cycles (Jobling 1994;Houlihan et al 2001;Jobling et al 2010). Food intake and the strength of response to baits have been shown to be low during the spawning period, which may reflect seasonal variations in feeding motivation (Fernö et al 1986;Løkkeborg et al 1989).…”

Environmental effects on behavioural development consequences for fitness of captive‐reared fishes in the wild

“…Again, successful modification requires careful consideration of the biology of the species used and consequences and costs for rearing routines need to be evaluated. For example, reducing rearing density may be comparatively simple to carry out but will increase the production cost per fish, whereas feeding reduction actually reduces food costs, but needs to be monitored carefully to give intended effects (Jobling et al , ).…”

Sublethal effects of angling and release on golden perch Macquaria ambigua: implications for reproduction and fish health

“…This was effective in the current study during early gametogenesis at T 1 but, despite the same anglers and methods, many M. ambigua ingested actively fished, baited lines during late gametogenesis at T 2 . Several hypotheses could explain these differences, including the fish may have become more accustomed to feeding in captivity by T 2 or the warmer water temperatures and advanced reproductive status of the fish might have elevated their metabolism, activity level, appetite or aggressiveness toward bait (Kadri et al, 1996;Jobling et al, 2012). Since the intention was to assess the effects of relatively mild angling (i.e.…”