|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 202, Issue 18 2413-2432, Copyright © 1999 by Company of Biologists
JOURNAL ARTICLES |
CD Wilga and GV Lauder
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA. cwilga@uci.edu
Pectoral fins are one of the major features of locomotor design in ray-finned fishes and exhibit a well-documented phylogenetic transition from basal to derived clades. In percomorph fishes, the pectoral fins are often used to generate propulsive force via oscillatory movements, and pectoral fin propulsion in this relatively derived clade has been analyzed extensively. However, in the plesiomorphic pectoral fin condition, exemplified by sturgeon, pectoral fins extend laterally from the body in a generally horizontal orientation, have been assumed to generate lift to balance lift forces and moments produced by the heterocercal tail, and are not oscillated to generate propulsive force. The proposal that pectoral fins in fishes such as sturgeon generate lift during horizontal locomotion has never been tested experimentally in freely swimming fishes. In this paper, we examine the function of pectoral fins in sturgeon swimming at speeds from 0.5-3.0 L s(-)(1), where L is total body length. Sturgeon were studied during steady horizontal locomotion as well as while sinking and rising in the water column. Pectoral fin function was quantified using three-dimensional kinematics to measure the orientation of the fin surface, digital particle image velocimetry (DPIV) was used to describe flow in the wake of the fin and to estimate force exerted on the water, and electromyography was used to assess pectoral fin muscle function. Sturgeon (size range 25-32 cm total length) swam horizontally using continuous undulations of the body with a positive body angle that decreased from a mean of 20 degrees at 0.5 L s(-)(1) to 0 degrees at 3.0 L s(-)(1). Both the angle of the body and the pectoral fin surface angle changed significantly when sturgeon moved vertically in the water column. Three-dimensional kinematic analysis showed that during steady horizontal swimming the pectoral fins are oriented with a negative angle of attack predicted to generate no significant lift. This result was confirmed by DPIV analysis of the pectoral fin wake, which only revealed fin vortices, and hence force generation, during maneuvering. The orientation of the pectoral fins estimated by a two-dimensional analysis alone is greatly in error and may have contributed to previous suggestions that the pectoral fins are oriented to generate lift. Combined electromyographic and kinematic data showed that the posterior half of the pectoral fin is actively moved as a flap to reorient the head and body to initiate rising and sinking movements. A new force balance for swimming sturgeon is proposed for steady swimming and vertical maneuvering. During steady locomotion, the pectoral fins generate no lift and the positive body angle to the flow is used both to generate lift and to balance moments around the center of mass. To initiate rising or sinking, the posterior portion of the pectoral fins is actively moved ventrally or dorsally, respectively, initiating a starting vortex that, in turn, induces a pitching moment reorienting the body in the flow. Adjustments to body angle initiated by the pectoral fins serve as the primary means by which moments are balanced.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  J. C Liao A review of fish swimming mechanics and behaviour in altered flows Phil Trans R Soc B, November 29, 2007; 362(1487): 1973 - 1993. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Brackenbury Kinematics and hydrodynamics of swimming in the mayfly larva J. Exp. Biol., February 22, 2004; 207(6): 913 - 922. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. G. Drucker and G. V. Lauder Function of pectoral fins in rainbow trout: behavioral repertoire and hydrodynamic forces J. Exp. Biol., March 1, 2003; 206(5): 813 - 826. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. K. Bartol, M. Gharib, D. Weihs, P. W. Webb, J. R. Hove, and M. S. Gordon Hydrodynamic stability of swimming in ostraciid fishes: role of the carapace in the smooth trunkfish Lactophrys triqueter (Teleostei: Ostraciidae) J. Exp. Biol., February 15, 2003; 206(4): 725 - 744. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. V. Lauder, J. C. Nauen, and E. G. Drucker Experimental Hydrodynamics and Evolution: Function of Median Fins in Ray-finned Fishes Integr. Comp. Biol., November 1, 2002; 42(5): 1009 - 1017. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Liao Swimming in needlefish (Belonidae): anguilliform locomotion with fins J. Exp. Biol., September 15, 2002; 205(18): 2875 - 2884. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. D. Wilga and G. V. Lauder Function of the heterocercal tail in sharks: quantitative wake dynamics during steady horizontal swimming and vertical maneuvering J. Exp. Biol., August 15, 2002; 205(16): 2365 - 2374. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. W. Webb Kinematics of plaice, Pleuronectes platessa, and cod, Gadus morhua, swimming near the bottom J. Exp. Biol., July 15, 2002; 205(14): 2125 - 2134. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Nauen and G. V. Lauder Hydrodynamics of caudal fin locomotion by chub mackerel, Scomber japonicus (Scombridae) J. Exp. Biol., June 15, 2002; 205(12): 1709 - 1724. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. G. Drucker and G. V. Lauder Experimental Hydrodynamics of Fish Locomotion: Functional Insights from Wake Visualization Integr. Comp. Biol., April 1, 2002; 42(2): 243 - 257. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Brackenbury Kinematics and hydrodynamics of an invertebrate undulatory swimmer: the damsel-fly larva J. Exp. Biol., March 1, 2002; 205(5): 627 - 639. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. W. Webb Control of Posture, Depth, and Swimming Trajectories of Fishes Integr. Comp. Biol., February 1, 2002; 42(1): 94 - 101. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. C. Nauen and G. V. Lauder Three-Dimensional Analysis of Finlet Kinematics in the Chub Mackerel (Scomber japonicus) Biol. Bull., February 1, 2001; 200(1): 9 - 19. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Nauen and G. V. Lauder Locomotion in scombrid fishes: visualization of flow around the caudal peduncle and finlets of the chub mackerel Scomber japonicus J. Exp. Biol., January 7, 2001; 204(13): 2251 - 2263. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E Drucker and G Lauder Wake dynamics and fluid forces of turning maneuvers in sunfish J. Exp. Biol., January 2, 2001; 204(3): 431 - 442. [Abstract] [PDF]
|
|
|
|
 |
|
 M. H. Dickinson, C. T. Farley, R. J. Full, M. A. Koehl, R. Kram, and S. Lehman How Animals Move: An Integrative View Science, April 7, 2000; 288(5463): 100 - 106. [Abstract] [Full Text]
|
|
|
|
|
|
G. V. Lauder Function of the Caudal Fin During Locomotion in Fishes: Kinematics, Flow Visualization, and Evolutionary Patterns Integr. Comp. Biol., February 1, 2000; 40(1): 101 - 122. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J Liao and G. Lauder Function of the heterocercal tail in white sturgeon: flow visualization during steady swimming and vertical maneuvering J. Exp. Biol., January 12, 2000; 203(23): 3585 - 3594. [Abstract] [PDF]
|
|
|
|
|
|
J. Nauen and G. Lauder Locomotion in scombrid fishes: morphology and kinematics of the finlets of the chub mackerel Scomber japonicus J. Exp. Biol., January 8, 2000; 203(15): 2247 - 2259. [Abstract] [PDF]
|
|
|
|
|
|
C. Wilga and G. Lauder Three-dimensional kinematics and wake structure of the pectoral fins during locomotion in leopard sharks Triakis semifasciata J. Exp. Biol., January 8, 2000; 203(15): 2261 - 2278. [Abstract] [PDF]
|
|
|
|
|
|
E. Drucker and G. Lauder A hydrodynamic analysis of fish swimming speed: wake structure and locomotor force in slow and fast labriform swimmers J. Exp. Biol., January 8, 2000; 203(16): 2379 - 2393. [Abstract] [PDF]
|
|
