The effect of temperature and thermal acclimation on the sustainable performance of swimming scup

Abstract

There is a significant reduction in overall maximum power output of muscle at low temperatures due to reduced steady-state (i.e. maximum activation) power-generating capabilities of muscle. However, during cyclical locomotion, a further reduction in power is due to the interplay between non-steadystate contractile properties of muscle (i.e. rates of activation and relaxation) and the stimulation and the length-change pattern muscle undergoes in vivo. In particular, even though the relaxation rate of scup red muscle is slowed greatly at cold temperatures (108C), warm-acclimated scup swim with the same stimulus duty cycles at cold as they do at warm temperature, not affording slow-relaxing muscle any additional time to relax. Hence, at 108C, red muscle generates extremely low or negative work in most parts of the body, at all but the slowest swimming speeds.Do scup shorten their stimulation duration and increase muscle relaxation rate during cold acclimation? At 108C, electromyography (EMG) duty cycles were 18% shorter in cold-acclimated scup than in warm-acclimated scup. But contrary to the expectations, the red muscle did not have a faster relaxation rate, rather, cold-acclimated muscle had an approximately 50% faster activation rate. By driving cold-and warm-acclimated muscle through cold-and warm-acclimated conditions, we found a very large increase in red muscle power during swimming at 108C. As expected, reducing stimulation duration markedly increased power output. However, the increased rate of activation alone produced an even greater effect. Hence, to fully understand thermal acclimation, it is necessary to examine the whole system under realistic physiological conditions.

The effects of acute temperature change on swimming performance in bluegill sunfishLepomis macrochirus

“…Randall and Brauner, 1991;Driedzic and Guesser, 1994;Farrell, 2002;Farrell, 2007;Stecyk et al, 2007). In fish, the effects of seasonal temperature changes on locomotor performance can largely be offset by acclimation of the muscular, respiratory and cardiovascular systems (Rome et al, 1985;Rome and Swank, 1992;Keen and Farrell, 1994;Beddow and Johnston, 1995;Egginton and Cordiner, 1996;Taylor et al, 1996;Johnston and Temple, 2002;Rome, 2007). Some species, however, must cope with more acute temperature shifts.…”

Combined effects of temperature and clomazone (Gamit®) on oxidative stress responses and B-esterase activity of Physalaemus nattereri (Leiuperidae) and Rhinella schneideri (Bufonidae) tadpoles

“…Temperature is an important variable that has direct impacts for aquatic ectotherms, such as amphibians. Changes on environmental temperature can alter behavior, metabolism, development, digestion and vision of amphibians, resulting in altered physiological performance in the environment (Murata and Yamauchi, 2005;Rome, 2007). Indeed, temperature can also interfere in the amphibian's responses triggered by environmental contaminants in natural systems Hooper et al, 2013;Noyes et al, 2009), and one of the current challenges in environmental toxicology is to understand how abiotic factors, such as temperature fluctuations, can interfere on the effects of chemical compounds in aquatic organisms.…”

Effects of pyrolytic and petrogenic polycyclic aromatic hydrocarbons on swimming and metabolic performance of zebrafish contaminated by ingestion

“…Aerobic metabolic scope (AMS; Brett, 1964;Fry, 1947Fry, , 1971) is defined as the difference between (i) the active metabolic rate (AMR), which is the highest metabolic rate the organism can sustain under maximal activity and (ii) the standard metabolic rate (SMR), the metabolic rate necessary to maintain vital functions and measured under resting conditions. Metabolic and swimming performance are known to be modulated by a set of environmental parameters, such as temperature (Blier et al, 1997;Farrell, 2007;Rome et al, 2007), dissolved oxygen (Diaz, 2001;Diaz et al, 2004) or pollutants (Johansen and Jones, 2011;Lefrançois and Claireaux, 2003;Marit and Weber, 2012;Shingles et al, 2001;Schurmann and Steffensen, 1997;Thomas et al, 2013).…”