The effect of fasting and refeeding on temperature preference, activity and growth of roach, Rutilus rutilus

Abstract

Most fish species are regularly subjected to periods of starvation during which a reduction of energy turnover might be favourable for the animal. This reduction of energy flux may be achieved by changes in thermal behaviour and/or swimming activity. We investigated such behavioural changes during starvation and subsequent refeeding in roach, Rutilus rutilus, with respect to energetic benefits and growth maximisation. Roach, acclimated to a wide range of temperatures (4, 12, 20, 24, 27 and 30 °C), were fed to excess, subjected to 3 weeks of starvation and subsequently refed in order to determine the temperature dependence of feeding rates, growth rates and conversion efficiency (K) under control conditions and during compensatory growth. When exposed to a thermal gradient, control animals preferentially selected a temperature of 26.8±0.9 °C, which is in the range of the optimal temperatures for feeding, growth and conversion efficiency. Starving fish showed a distinct circadian pattern of the mean selected temperature (MST). They migrated to cooler water in the dark (MST=22.8±1.1 °C) but returned to warmer water during daytime. This behaviour may be regarded as a trade-off between the potentially higher food density in warmer water areas and the energetic benefit of selecting cooler water patches. The circadian pattern of MST was gradually abandoned upon refeeding and control values were reached again after 3 weeks. Energetically more effective than behavioural hypothermia was the reduction of swimming activity. During starvation, activity peaks were slightly lower than under control conditions and mean daily activity decreased by about 50%. Swimming velocity, however, was not affected by feeding regime. After a period of starvation fish showed compensatory growth at all temperatures, even below 12 °C, where these animals normally do not grow. This suggests that after a period of starvation the critical temperature for growth shifts to lower values.

Temperature preference in Rhodnius prolixus, effects and possible consequences

“…A low level of oxygen consumption is reached 10 days after feeding, about half that observed 1 day after feeding (Okasha, 1968b). As in some fishes (Wurtsbaugh & Neverman, 1988;Sogard & Olla, 1996;van Dijk et al, 2002), the fire ant (Solenopsis invicta) (Porter & Tschinkel, 1993) and T. infestans (Lazzari, 1991), R. prolixus can modulate metabolic activity and rate of nutrient conversion by means of behavioural thermoregulation. That is, just after feeding the insects might remain at relatively high temperatures in order to increase their metabolic rates and nutrient transformation.…”

“…This increase in metabolism exhibited by ectothermic animals with rising temperature can be mostly explained by an increase in activity (Wigglesworth, 1972). Several ectothermic animals adjust their body temperature and metabolism behaviourally (Remmert, 1985;Vielmetter, 1958;Wurtsbaugh & Neverman, 1988;van Dijk, et al, 2002). The effect of environmental temperature on insects seems to vary depending on different physiological processes.…”

Arctic charr (Salvelinus alpinus) squeezed in a complex fish community dominated by perch (Perca fluviatilis)

“…In roach from gill net catches (body lengths 137 -290 mm), the mean δ 15 N value was similar to small perch, i.e. approximately also observed in other lakes with these species (Brabrand & Borgstrøm 2000;van Dijk et al 2002;Linløkken & Haugen 2006). Burbot and Arctic charr, on the other hand, often staying in deeper water with lower temperatures (Hofmann & Fischer 2002;Klemetsen et al 2003), may have a lower catchability by gillnetting, and thereby a lower CPUE due to low temperatures (Borgstrøm 2000).…”

Effects of feeding on thermoregulatory behaviours and gut blood flow in white sturgeon (Acipenser transmontanus) using biotelemetry in combination with standard techniques

“…These species seek colder temperatures when food is scarce. This has been observed in roach and is thought to minimise metabolic rate (van Dijk et al, 2002). When able to select temperatures, roach, starved for three weeks, showed a pattern of moving into cooler waters during night hours.…”

“…Sometimes a combination of several factors may trigger individuals to change their temperature preference. For example, feeding status in combination with time of day and perhaps also with ontogeny influence temperature preference in larvae of Bear Lake sculpin Cottus extensus (Wurtsbaugh and Neverman, 1988) and adult roach Rutilus rutilus (van Dijk et al, 2002).…”