QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online September 19, 2006
Journal of Experimental Biology 209, 3708-3718 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02449

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hale, M. E. Articles by Westneat, M. W. Search for Related Content PubMed PubMed Citation Articles by Hale, M. E. Articles by Westneat, M. W.

Pectoral fin coordination and gait transitions in steadily swimming juvenile reef fishes

Melina E. Hale^1,2,3,*, Ryan D. Day^1,, Dean H. Thorsen¹ and Mark W. Westneat⁴

¹ Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637, USA
² Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, USA
³ Committee on Computational Neuroscience, The University of Chicago, Chicago, IL 60637, USA
⁴ Department of Zoology, Field Museum of Natural History, 1400 South Lakeshore Drive, Chicago, IL 60605, USA

View larger version (152K): [in a new window]   Fig. 1. Kinematics of (A) alternating and (B) synchronous pectoral fin propulsion in ventral view during steady swimming in the blue damselfish Pomacentrus pavo. (A) At 2 BL s-1, the fish swims by alternating its pectoral fins at approximately 180° out of phase from one another. At 0 ms the left (upper) pectoral fin is protracted (abducted) and at 17 ms the left is retracted (adducted) while the right (lower) fin begins protraction. At 50 ms the left fin is seen during protraction and right during retraction. (B) At higher speeds (7 BL s-1), damselfish switch gaits to an in phase fin beat pattern with simultaneous protraction (frame 17 ms and 67 ms) and retraction (0 and 50 ms). At 33 ms the fins are shown in mid-retraction phase.

View larger version (152K): [in a new window]   Fig. 2. The transition between alternating and synchronous pectoral fin coordination during steady swimming in the blue damselfish Pomacentrus pavo at a critical swimming speed of approximately 4 BL s-1. This gait transition occurs rapidly, within 1-2 fin strokes. Asynchronous swimming (left panels) is seen from 0-33 ms, then is partially out of phase during the transition (33-67 ms). Mostly synchronous locomotion is seen from 83-150 ms (right panels).

View larger version (31K): [in a new window]   Fig. 3. Representative kinematic data for angular rotation of left and right pectoral fins of juvenile Pomacentrus pavo during (A) slow, alternating fin strokes, (B) a transition from synchronous to alternating fin coordination and back again, and (C) synchronous fin strokes at higher speed.

View larger version (13K): [in a new window]   Fig. 4. Phase lag of left and right pectoral fins with increasing swimming velocity. Points are the mean of 5-8 fin beats in a swimming sequence. Note the sharp gait transition from alternate to synchronous fin motions between 3 and 4 BL s-1.

View larger version (75K): [in a new window]   Fig. 5. Transitions between synchronous pectoral propulsion and axial propulsion. (A) Video images showing axial propulsion (0.167-0.217 s) followed by synchronous pectoral swimming with body held straight (0.267-0.3 s). (B) Kinematics of synchronous pectoral rotation (blue and green), ceasing at about 0.15 s accompanied by two strokes of the caudal fin (red) and then pectoral propulsion resuming at 0.25 s.

View larger version (19K): [in a new window]   Fig. 6. Frequency (A) and amplitude (B) of pectoral fin beats during increasing swimming velocity trials in Pomacentrus pavo. Both frequency and amplitude increase with speed, smoothly across the transition to synchronous fin beats at 3-4 BL s-1. Transition points include a range of behaviors in which switching between modes was observed.

View larger version (18K): [in a new window]   Fig. 7. Reduced frequency (A) and advance ratio (B) of juvenile pectoral fin locomotion in Pomacentrus pavo.

View larger version (20K): [in a new window]   Fig. 8. Distance traveled by the tip of the snout each frame illustrating (A) fore-aft excursion due to forward thrust and (B) lateral motion (yaw) during pectoral fin locomotion in Pomacentrus pavo.