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Titolo:
THE MECHANICAL POWER OUTPUT AND HYDROMECHANICAL EFFICIENCY OF NORTHERN PIKE (ESOX-LUCIUS) FAST-STARTS
Autore:
FRITH HR; BLAKE RW;
Indirizzi:
LGL LTD,9768 2ND ST SIDNEY BC CANADA UNIV BRITISH COLUMBIA,DEPT ZOOL VANCOUVER BC CANADA
Titolo Testata:
Journal of Experimental Biology
fascicolo: 9, volume: 198, anno: 1995,
pagine: 1863 - 1873
SICI:
0022-0949(1995)198:9<1863:TMPOAH>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANGELFISH PTEROPHYLLUM-EIMEKEI; FORCE-VELOCITY RELATIONSHIP; MARLIN MAKAIRA-NIGRICANS; TROUT SALMO-GAIRDNERI; HIGH-SPEED FILM; SKELETAL-MUSCLE; RAINBOW-TROUT; MAXIMUM ACCELERATIONS; ESCAPE RESPONSE; TELEOST FISH;
Keywords:
FAST-START; EFFICIENCY; POWER; NORTHERN PIKE; ESOX LUCIUS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
44
Recensione:
Indirizzi per estratti:
Citazione:
H.R. Frith e R.W. Blake, "THE MECHANICAL POWER OUTPUT AND HYDROMECHANICAL EFFICIENCY OF NORTHERN PIKE (ESOX-LUCIUS) FAST-STARTS", Journal of Experimental Biology, 198(9), 1995, pp. 1863-1873

Abstract

The mechanical power output and hydrodynamic efficiency of northern pike, Esox lucius, during acceleration from rest (fast-start) are calculated from hydrodynamic theory for two kinematic patterns, C-starts (used in escape) and S-starts (used in prey capture). The Weihs model isemployed and modified to calculate the mechanical power produced by afish during a fast-start, A term is included for the power required to accelerate body sections laterally, Lateral deceleration of fish body sections and their associated added mass are expressed as an active process requiring energy expenditure or as a passive process requiringno energy expenditure, In addition, two methods of calculating usefulpower (the power used to accelerate the virtual mass of the fish, i.e. fish body mass + longitudinal added mass, in the direction of motion), one derived from the Weihs model and the second by summing the changes in kinetic energy of the virtual mass of the fish during a fast-start, are compared and found to give similar estimates of useful power (not significantly different; differences average 22%). Comparisons ofthe kinematics and performance of C-and S-starts reveal that C-startsare consistently terminated after two tail flips (stages 1 and 2) whereas S-starts continue for 3-6 tail flips (stages 3-6), In addition, acceleration during C-starts is more rapid and velocities are higher (2.3-2.8 m s(-1)) than during S-starts (08. and 1.8ms(-1)) over the first 100ms. However, the peak velocities achieved during S-starts and C-starts are similar over the duration of a fast-start, The superior acceleration rates achieved during the initial stages of a C-start can be explained, in part, by the use of greater maximum angles of attack, higher lateral and perpendicular velocities and larger maximum forces bythe caudal fin. Hydrodynamic efficiencies for fast-starts range from 0.16 to 0.39, values that are lower than those observed during either burst-and-coast or steady swimming, Efficiencies are lower for S-starts than for C-starts during the first two tail beats. S-start efficiencies increase with each subsequent tail flip and the maximum efficiencies realised are similar to those achieved during C-starts. Power output during C- and S-starts (449.0 and 394.9 Wkg(-1) muscle fibre, respectively) approaches the theoretical maximum for vertebrate striated muscle (500 W kg(-1)). Also, the inferred muscle stress is close to the predicted optimum for maximum power output, at 30% of the maximum isometric stress recorded for isolated fast muscle fibres, These measurements suggest that fast-start performance is near a physiological limit and is probably constrained by muscle function, The superior acceleration rates achieved by C-starts over S-starts are explained in part by differences in hydrodynamic efficiency, whereas power outputs are similar.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 09:09:20