Maximum Sustained Swimming Speed Research Articles

The Roles of Pink and Red Muscle in Powering Steady Swimming in Scup,Stenotomus chrysops

Synopsis. Fishes power steady, undulatory swimming using both red and pink muscle. In this study we examined the roles of the two fiber types in generating power for swimming by using a two-step technique. First, in vivo data is collected from swimming fish, and second, the electrical activity and muscle length change conditions recorded in vivo are recreated in vitro with isolated muscle bundles. Force production and power generation by muscle during swimming can then be estimated. In scup, both red and pink muscle are recruited to power swimming at the maximum sustained swimming speed. For both fiber types, the duration of electrical activity decreases from anterior to posterior. However, the amplitude of muscle length change increases anterior to posterior. Massspecific power production increases posteriorly for both muscle types. The faster contraction kinetics of pink muscle translate to higher power pro? duction by pink muscle relative to red muscle for all longitudinal positions of the fish. Determination of absolute power production, based on massspecific power and muscle mass, shows that the posterior regions of the fish generate the most power for swimming. At 20?C, red muscle generates more absolute power than pink due to its higher muscle mass. However, at 10?C, pink muscle generates more absolute power than red, because red muscle produces little or no positive power for all longitu? dinal positions.

Contraction dynamics and power production of pink muscle of the scup (Stenotomus chrysops).

Although the contribution of red muscle to sustained swimming in fish has been studied in detail in recent years, the role of pink myotomal muscle has not received attention. Pink myotomal muscle in the scup (Stenotomus chrysops) lies just medial to red muscle, has the same longitudinal fibre orientation and is recruited along with the red muscle during steady sustainable swimming. However, pink muscle has significantly faster rates of relaxation, and the maximum velocity of shortening of pink muscle (7.26 +/- 0.18 muscle lengths s-1, N = 9, at 20 degrees C, and 4.46 +/- 0.15 muscle lengths s-1, N = 6, at 10 degrees C; mean +/- S.E.M.) is significantly faster than that of red muscle. These properties facilitate higher mass-specific maximum oscillatory power production relative to that of red muscle at frequencies similar to the tailbeat frequency at maximum sustained swimming speeds in scup. Additionally, pink muscle is found in anatomical positions in which red muscle is produces very little power during swimming: the anterior region of the fish, which undergoes the lowest strain during swimming. Pink muscle produces more oscillatory power than red muscle under low-strain conditions (+/- 2-3%) and this may allow pink muscle to supplement the relatively low power generated by red muscle in the anterior regions of swimming scup.

Respiratory gas exchange, nitrogenous waste excretion, and fuel usage during aerobic swimming in juvenile rainbow trout

The types of fuel burned by juvenile rainbow trout (17 g) during a 58-h period of aerobic sustained exercise were studied by respirometry. Attempts to measure fuel usage by depletion (thecompositional approach) in these same fish were unsuccessful due to lack of detectable changes in proximate body composition. O2 consumption, CO2 excretion, and nitrogenous waste excretion (ammonia-N plus urea-N) were measured in individual fish swum continuously at 55% and 80% of maximum sustainable swimming speed and in non-swimming controls. O2 consumption and CO2 excretion increased with swimming speed, and decreased over time. Absolute rates of N excretion were independent of swimming speed and time.Instantaneous aerobic fuel use, as calculated from the respiratory quotients and nitrogen quotients, was approximately 47% lipid, 30% protein, and 23% carbohydrate in non-swimmers at the start of the experiment. With increased swimming speed there was no change in absolute rates of protein oxidation, while lipid and carbohydrate oxidation both increased. Therefore, the relative protein contribution decreased with increasing speed but increased with swimming duration as the oxidation of other fuels declined over time. However, lipid oxidation predominated at all speeds and at all times. The relative contribution of carbohydrate increased with swimming speed and decreased over time. These results suggest that swimming becomes more efficient over time and help resolve uncertainties in the literature. We conclude that lipid is the main fuel of aerobic exercise, that protein catabolism is kept at minimum levels necessary for maintenance, and that carbohydrate oxidation becomes more important with increased white muscle recruitment at higher speed.

Larval Fish Distribution and Microhabitat Use in Free-Flowing and Regulated Rivers

The ecology of larval fish is poorly documented in natural and altered rivers even though larval fish distributions and habitat requirements are often distinctly different from larger and older fish. Larval fish were collected every two weeks from late winter to late summer in 1988 and 1989 in the Tallapoosa River, a highly flow-regulated river, and the Cahaba River, an unregulated river, in Alabama. Larval fish were collected in offshore waters using a pushnet and in potential nursery habitat along the river margins using 1-im, 500-jum mesh seine. Nursery habitat was defined as shallow water (< 1.3 m) with currents less than the maximum sustained swimming speed of larvae (estimated as 8.4 cm/sec). A total of 17,675 larvae were collected in 1529 samples. Most (77%) larvae were collected in the unregulated river, and a majority of larvae (83%) were captured by seining in nursery habitat. Identifications and analysis were done at the family level, and taxonomic diversity was similar between rivers and between nearshore and offshore collections. The abundance and taxonomic composition of the larval fish assemblages varied by river, year, and Tallapoosa River study site. The most common families were catostomidae, cyprinidae, percidae, and centrarchidae. Nursery habitat at the most flow-regulated site had very low abundances of larvae and a distinctly different family composition from the other sites. All taxa commonly recorded in the Cahaba River and the least regulated Tallapoosa River study site used a statistically distinct subset of available microhabitats in nursery waters. There was little evidence for microhabitat specialization by larval fish at the most regulated Tallapoosa River site. Flow regulation appeared to reduce the abundance of larval fish in nursery habitat, alter taxonomic composition, and disrupt microhabitat relations. Flow regulation and the associated degradation of nursery habitat appears to be a potential threat to the conservation of natural and diverse riverine fish faunas.

Assessment of Maximum Sustainable Swimming Performance in Rainbow Trout (Oncorhynchus Mykiss)

Levels of swimming activity in fishes have been divided into three categories on the basis of the time a given speed can be maintained before the onset of fatigue (Beamish, 1978): sustained (more than 200 min), prolonged (20 s to 200 min) and burst swimming (less than 20 s). The locomotory capacity of a given species reflects both its lifestyle and its body form, although definitions of performance may vary. It is generally accepted that only the aerobic ('red') muscle fibres should be active at truly sustainable swimming speeds, i.e. at speeds that can be maintained indefinitely without fatigue. However, the standard laboratory method of evaluating the maximum sustainable swimming speed (Ucrit; Brett, 1964) almost certainly entails the recruitment of at least some of the rapidly fatigable fast glycolytic ('white') fibres at sub-critical speeds and undoubtedly complicates the evaluation of maximal cardiovascular performance. It would therefore be useful to have an objective and reproducible measure of truly sustainable performance that, by definition, relies solely on aerobic muscle activity. Electromyography (EMG) has been used to examine the pattern of white muscle recruitment following thermal acclimation in striped bass, Morine saxatilis (Sisson and Sidell, 1987). We wished to incorporate this method into a study of the acclimatory responses to chronic changes in environmental temperature of the cardiovascular and locomotory systems in rainbow trout (Wilson and Egginton, 1992). The present communication presents results on the cardiovascular performance and blood chemistry, at rest and during maximal aerobic exercise, of rainbow trout acclimated to 11 &deg;C, as a validation of the methodology currently in use with fish acclimated to seasonal temperature extremes (Taylor et al. 1992). Different acclimation temperatures are known to produce compensatory changes in the relative proportions of red and white muscle mass (Sidell and Moerland, 1989). The aim of these continuing investigations is to compare the anatomical, cardiovascular and locomotory limitations to aerobic exercise over the full temperature range of a eurythermal fish species.

Cardiovascular and respiratory physiology of tuna: adaptations for support of exceptionally high metabolic rates

Both physical and physiological modifications to the oxygen transport system promote high metabolic performance of tuna. The large surface area of the gills and thin blood-water barrier means that O2 utilization is high (30–50%) even when ram ventilation approaches 101 min−1kg−1. The heart is extremely large and generates peak blood pressures in the range of 70–100 mmHg at frequencies of 1–5 Hz. The blood O2 capacity approaches 16 ml dl−1 and a large Bohr coefficient (−0.83 to −1.17) ensures adequate loading and unloading of O2 from the well buffered blood (20.9 slykes). Tuna muscles have aerobic oxidation rates that are 3–5 times higher than in other teleosts and extremely high glycolytic capacity (150 μmol g−1 lactate generated) due to enhanced concentration of glycolytic enzymes. Gill resistance in tuna is high and may be more than 50% of total peripheral resistance so that dorsal aortic pressure is similar to that in other active fishes such as salmon or trout. An O2 delivery/demand model predicts the maximum sustained swimming speed of small yellowfin and skipjack tuna is 5.6 BL s−1 and 3.5 BL sec−1, respectively. The surplus O2 delivery capacity at lower swimming speeds allows tuna to repay large oxygen debts while swimming at 2–2.5 BL s−1. Maximum oxygen consumption (7–9 × above the standard metabolic rate) at maximum exercise is provided by approximately 2 × increases in each of heart rate, stroke volume, and arterial-venous O2 content difference.

Swimming performance, whole body ions, and gill Al accumulation during acclimation to sublethal aluminium in juvenile rainbow trout (Oncorhynchus mykiss)

Juvenile rainbow trout (2-5 g) were chronically exposed (for 22 days) to acidified softwater (Ca(2+) = 25 μEq/l, pH 5.2) in the presence or absence sublethal Al (30 μg/l). Al-exposed fish (5.2/Al group) suffered 20% whole body Na(+) and Cl(-) losses and a 30% reduction in the maximum sustainable swimming speed (Ucrit) over the initial 7 days. These disturbances were approximately 2 fold greater than those observed in the fish exposed to low pH alone (5.2/0 group). However, whole body ion levels were completely restored in the 5.2/Al fish by day 22, whereas they merely stabilized at a new reduced level in the 5.2/0 group. Increased resistance to acutely lethal Al (200 μg/l at pH 5.2) was observed from day 17 onwards in the 5.2/Al fish. Despite this acclimation and recovery of whole body ions, Ucrit remained significantly lower than in the 5.2/0 group throughout. Growth on a restricted diet of 1% body wt. /day was normal in the 5.2/0 group compared with controls maintained in pH 6.5 softwater, whereas 5.2/Al fish suffered a 50% reduction in growth rate on the same diet. The 5.2/Al fish accumulated large amounts of Al on the gills, reaching an initial peak after 4 days, followed by a decline at 7 days, and a secondary rise thereafter. Therefore acclimation and recovery of whole body ionic status was not associated with a reduction in the gill Al burden. Some of the metabolic costs of acclimation to Al, namely a continued impairment of swimming speed and growth, are discussed in light of the physiological and structural changes reported to occur at the gills.

Swimming Velocities and Behavior of Blue Crab (Callinectes sapidus Rathbun) Megalopae in Still and Flowing Water

Habitat selection capabilities of the recruiting larval stages of marine invertebrates are limited, in part, by their ability to maneuver in flowing water. Distributional and experimental evidence suggest that blue crab (Callinectes sapidus) megalopae may preferentially settle into vegetated habitats. However, the behavior and swimming capabilities of megalopae in flowing water have not previously been investigated. Laboratory experiments were conducted in a small, recirculating seawater flume to determine the swimming response of megalopae to varying flow velocities. Nighttime trials were conducted at six flow velocities: 0, 1.9, 3.6, 4.8, 6.3, and 9.3 cm s−1. Behavior and swimming velocities of field-collected C. sapidus megalopae were video recorded. Megalopae exhibited negative phototaxis and were found in the water column at all flows in the dark. The maximum sustained swimming speed observed was 12.6 cm s−1 and the mean swimming speed in still water was 5.0 cm s−1, with short bursts in excess of 20 cm s−1. Megalopae frequently oriented into the current and were capable of swimming upstream against the current at flow speeds <4.8 cm s−1; at greater velocities they were not able to do so. The results suggest that at low to moderate current velocities C. sapidus megalopae have the ability to actively move in search of settlement sites and to maintain their positions in desirable sites rather than relying strictly on passive movements by currents.

Power Output of Two Sizes of Atlantic Salmon (Salmo Salar) at Their Maximum Sustained Swimming Speeds

ABSTRACT The maximum sustained swimming speeds (Ums) for large (0.45 m long) and small (0.15m) Atlantic salmon were respectively 0.91 ms−1 and 0.54ms−1. Video and ciné films of fish swimming close to Ums were analysed to obtain variables required for the application of two hydrodynamic models, those of Lighthill and Yates, to determine the mean thrust and mean power output at these swimming speeds (U) close to Ums. A large fish (‘Salmon’) and a small fish (‘Smolt’) were selected for analysis. For salmon using Lighthill’s model, and , and using Yates’ model, and (U=0.87ms−1=0.96Ums). For smolt using Lighthill’s model, and , and using Yates’ model, and (U=0.37ms−1=0.69Ums). The power output for smolt swimming at 0.69Ums was corrected to that required to swim at Ums, giving (Lighthill’s model) and (Yates’ model). At Ums it was assumed that all the red muscle was used. Two fish were selected from each size group and cross-sectioned to estimate their red muscle masses. Using a maximum mass-specific power output of 5–8 W kg−1 for slow red muscle fibres allowed us to calculate that the large and small fish have a power output capacity of 0.125–0.3 W and 0.007–0.019 W, respectively. The power output values at Ums derived from the different approaches for the large (0.25–0.26 W) and small (0.0059–0.0074 W) salmon agree closely. Effects of scaling are discussed.

Swimming endurance of the Atlantic cod, Gadus morhua L., at low temperatures

Swimming speed and endurance of the Atlantic cod, Gadus morhua L., were measured in a swimming flume at temperatures between −0.3 and 1.4°C. The maximum sustained swimming speed for fish 0.36–0.52 m long was between 0.9 and 1.0 body lengths per second (BL s −1). Endurance reduces as swimming speed is increased. All fish measured were unable to swim for more than 1 min at 3 BL s −1. The results are discussed in relation to the selectivity of survey trawls in northwest Atlantic waters where the cod are found in waters of temperatures ranging from < 0 to > 8°C.

The Influence of Temperature on Muscle Velocity and Sustained Performance in Swimming Carp

The aim of this study was to evaluate how fish locomote at different muscle temperatures. Sarcomere length excursion and muscle shortening velocity, V, were determined from high-speed motion pictures of carp, Cyprinus carpio (11-14 cm), swimming steadily at various sustained speeds at 10, 15 and 20 degrees C. In the middle and posterior regions of the carp, sarcomeres of the lateral red muscle underwent cyclical excursions of 0.31 microns, centered around the resting length of 2.06 microns (i.e. from 1.91 to 2.22 microns). The amplitudes of the sarcomere length excursions were essentially independent of swimming speed and temperature. As tail-beat frequency increased linearly with swimming speed regardless of temperature, the sarcomeres underwent the same length changes in a shorter time. Thus, V increased in a linear and temperature-independent manner with swimming speed. Neither temperature nor swimming speed had an influence on tail-beat amplitude or tail height. Our findings indicate that muscle fibres are used only over a narrow, temperature-independent range of V/Vmax (0.17-0.36) where power and efficiency are maximal. Carp start to recruit their white muscles at swimming speeds where the red muscle V/Vmax becomes too high (and thus power output declines). When the V/Vmax of the active muscle falls too low during steady swimming, carp switch to 'burst-and-coast' swimming, apparently to keep V/Vmax high. Because Vmax (maximum velocity of shortening) of carp red muscle has a Q10 of 1.63, the transition speeds between swimming styles are lower at lower temperatures. Thus, carp recruit their white anaerobic muscle at a lower swimming speed at lower temperatures (verified by electromyography), resulting in a lower maximum sustainable swimming speed. The present findings also indicate that, to generate the same total force and power to swim at a given speed, carp at 10 degrees C must recruit about 50% greater fibre cross-sectional area than they do at 20 degrees C.

Endurance at intermediate swimming speeds of Atlantic mackerel, Scomber scombrus L., herring, Clupea harengus L., and saithe, Pollachius virens L.

Endurance and swimming speed were measured in mackerel, herring and saithe when they were induced by the optomotor response to swim at prolonged speeds along a 28‐m circular track through still water in a 10‐m diameter gantry tank. The maximum sustained swimming speed (Ums was measured as body lengths per second (b.l.s−1) for each species and for saithe of different size groups. Herring with Ums of 4.06 b.l.s−1 (25.3 cm, 13.5°C) were the fastest, mackerel Ums was 3.5 b.l.s1 (33 cm, 11.7°C) and saithe (14.4°C) showed a size effect where Ums at 25 cm was 3.5 b.l.s1 and at 50 cm 2.2 b.l.s1. When swimming at speeds higher that Ums, all three species showed reduced endurance as speed increased. How the curved track reduces the swimming speed is discussed.

Swimming capabilities of Mesozoic marine reptiles: implications for method of predation

Body shape and mode of swimming were major factors that affected the swimming capabilities of Mesozoic marine reptiles. By estimating the total drag and the amount of energy available through metabolism, the maximum sustained swimming speed was calculated for 115 marine reptile specimens. Calculated sustained swimming speeds range from 1.8 to 2.7 m/sec, but are probably too high by as much as a factor of two. Mesozoic marine reptiles were probably much slower than modern toothed whales. The diversification of fast, agile teleost fish in the Cretaceous may have therefore contributed to the decline of the marine reptiles.Long-bodied reptiles appear to have had slower sustained swimming speeds than deep-bodied forms of the same length. For a given length, ichthyosaurs were probably faster sustained swimmers than plesiosaurs, and plesiosaurs were probably faster sustained swimmers than crocodiles and mosasaurs. This suggests that the long-bodied forms probably used an ambush technique to capture prey, to maximize the range of possible prey and to minimize competition with the faster pursuit predators.

Observations of poor swimming performance among hatchery-reared rainbow trout, Salmo gairdneri

The swimming performance, as judged by maximum sustained swimming speed, of rainbow trout from a fish farm in S.W. England, is low when compared to previously published values for this species. This may be a localised peculiarity resulting from hatchery selection and rearing procedures.

Coronary ligation reduces maximum sustained swimming speed in chinook salmon, Oncorhynchus tshawytscha

1. 1. The maximum aerobic swimming speed of Chinook salmon ( Oncorhynchus tshawytsha) was measured before and after ligation of the coronary artery. 2. 2. Coronary artery ligation prevented blood flow to the compact layer of the ventricular myocardium, which represents 30% of the ventricular mass, and produced a statistically significant 35.5% reduction in maximum swimming speed. 3. 3. We conclude that the coronary circulation is important for maximum aerobic swimming and implicit in this conclusion is that maximum cardiac performance is probably necessary for maximum aerobic swimming performance.

Contractile responses to temperature in the locomotory musculature of striped bass Morone saxatilis

AbstractThe effects of temperature on contractile function of isolated, chemically skinned red (slow oxidative) and white (fast glycolytic) fibers of skeletal muscle from thermally acclimated striped bass (Morone saxatilis) were determined. Acclimation to 10° or 25°C has no significant effect on maximum isometric tension (Po) or maximum unloaded contraction velocity (Vo) of fibers of either muscle type. Sensitivity to acute changes in temperature is markedly greater for slow‐twitch fibers than for white, fast‐twitch fibers. Q10 (15–5°C) of Vo is 1.58 and 2.27 and R10 (15–5°C; analogous to Q10, but for parameters that are not rate functions) of Po is 1.57 and 2.17 for fibers from white and red muscle, respectively. R10 of maximum attainable power output is 1.29 for white and 4.50 for red fibers. Power for low speed, sustained swimming is derived exclusively from red muscle in striped bass, permitting comparisons between swimming performance and contractile capacity to be drawn. For maximum sustainable swimming speed at 15°C, calculated contraction velocity of a red muscle fiber corresponds to the maximum power output of a single fiber of red muscle at 15°C. Thermal sensitivity of red muscle power output predicts that maximum sustained swimming speed of striped bass will be severely impaired at cold temperatures. However, cold acclimation induces a proliferation of the red muscle mass that may ameliorate the thermal sensitivity of red muscle contractile function.

Aerobic metabolic scope and swimming performance in juvenile cod, Gadus morhua L.

Juvenile cod (Gadus morhua) were made to swim in a tunnel respirometer to determine the oxygen consumption during swimming at different speeds. Results were compared with measurements of standard and active metabolic rates in static respirometers before and after intense exercise. The oxygen consumption at maximum sustainable swimming speed was considerably lower than the peak oxygen consumption following exhausting exercise. It is suggested that these fish have a poorly developed system of aerobic (red) locomotor muscles which do not normally make a major demand upon oxygen consumption. Apparent specific dynamic action following feeding and repayment of oxygen debt following anaerobic exercise can each give rise to greater rates of oxygen consumption. Following exhausting exercise there is a delay of about 1 h before oxygen consumption reaches a peak level some 40% higher than the peak level observed during sustained swimming.

Swimming and Diving in Tufted Ducks, Aythya Fuligula, with Particular Reference to Heart Rate and Gas Exchange

ABSTRACT In six tufted ducks there was a linear relationship between heart rate and oxygen consumption when swimming at different velocities. Mean oxygen consumption at mean duration of voluntary dives was 3·5 times resting and not significantly different from that at maximum sustainable swimming speed. Contrary to an earlier report (Prange &amp; Schmidt-Nielsen, 1970), leg beat frequency increased with increased swimming speed. Although heart rate at mean dive duration was 51% higher than the resting value, it was a significant 59 beats min−1 lower than predicted from the heart rate/oxygen consumption relationship obtained during swimming. This relationship is, therefore, of no use for predicting oxygen consumption from heart rate during diving, nor incidentally during transient changes during air breathing. It is concluded that during voluntary diving in tufted ducks there is a balance between the cardiovascular responses to forced submersion (bradycardia, selective vasoconstriction) and to exercise in air (tachycardia and vasodilatation in active muscles), with the bias towards the latter.

Red and white muscle fibre activity in swimming skipjack tuna, Katsuwonus pelamis (L.)

To test the hypothesis that white muscle fibre portions of the myotomes are used at sustainable swimming speeds, skipjack tuna, Katsuwonus pelamis, were forced to swim against various current velocities in a water tunnel while electrical activity of the red and white muscle fibres was simultaneously recorded. Eight fish were tested, five fish graded white muscle fibres into activity at swimming speeds above their minimum hydrostatic equilibrium speed, but well below the estimated maximum sustainable swimming speed of skipjack tuna. Three other fish showed white muscle fibre activity at minimum swimming speeds, a possibly abnormal condition.

A study of the swimming performance of the Crucian carp Carassius carassius (L.) in relation to the effects of exercise and recovery on biochemical changes in the myotomal muscles and liver

A study has been made of the maximum sustained swimming speed of Crucian carp Carassius carassius (L.) using a fixed velocity technique. The data obtained from swimming tests on 214 carp have been analysed using the method of probit analysis. The 50% fatigue level for 13–16 cm fish acclimated to 9.5±0.6°C has been estimated to be 3.35 lengths/sec. Biochemical measurements have been made on the red and white myotomal muscles and liver of fish subjected to both varying intensities of sustained swimming and short periods of vigorous swimming. Free creatine was found to increase only during high speed swimming in the white muscle. Elevated lactate concentrations occurred at both low and high sustained swimming speeds in the red superficial muscle but not during short periods of strenuous exercise. Glycogen depletion from the red musculature also only took place at the sustained swimming speeds investigated. The reverse situation was operative in the white muscle, significant glycogen depletion occurring only at the highest swimming speed studied. Lactate levels were only significantly different from non‐exercised fish in the fish swimming at the higher velocities. The effects of periods of recovery following 200 min of sustained swimming were also investigated. White muscle lactate was at a higher level than non‐exercise fish 5 h post‐exercise, while both red muscle glycogen and lactate rapidly returned to pre‐exercise concentrations. Biochemical measurements on the myotomal muscle types have been discussed in relation to the swimming performance of the fish and the division of labour between red and white fibres.