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UBC Theses and Dissertations
Oblique swimming in characoid fishes with special reference to the genus Nannostomus Gunther 1872 Chondoma, Emmanuel C.
Abstract
The hydrodynamics and mechanics of obliquely swimming characoid species Chilodus punetatus, Nannostomus eques, Nannostomus unifasciatus, Thayeria. boehlkei and Thayeria obliqua are investigated. In Chilodus punctatug, Nannostomus eques and Nannostomus unifasciatus the position of the centre of mass relative to the centre of buoyancy is the reverse of what would be expected from their pitch. The centre of mass is in front of the centre of buoyancy in the two Nannostomus species which swim with a positive pitch and vice versa in Chilodus punctatus which swims with negative pitch. The relative positions of these two centres are in such a way that they help to bring the fish horizontal during fast swimming. Pitch in these species is maintained by the action of the pectoral and caudal fins. In the two Thayeria species the centre of mass is behind the centre of buoyancy and their separation is responsible for the positive pitch. The fins are used to correct for this pitch to the desirable level. The enlarged lower lobe of the caudal fin in Nannostomus species has an epibatic effect and does not contribute to the forces responsible for the pitch in hovering as previously proposed. Relative vertebrae size in Nannostomus eques and Nannostomus unifasciatus when compared to Nannostomus becfordi and Nannostomus trifasciatus which swim horizontally show adaptations towards a strategy of rapid start from rest.
Item Metadata
Title |
Oblique swimming in characoid fishes with special reference to the genus Nannostomus Gunther 1872
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1979
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Description |
The hydrodynamics and mechanics of obliquely swimming characoid species Chilodus punetatus, Nannostomus eques, Nannostomus unifasciatus, Thayeria. boehlkei and Thayeria obliqua are investigated. In Chilodus punctatug, Nannostomus eques and Nannostomus unifasciatus the position of the centre of mass relative to the centre of buoyancy is the reverse of what would be expected from their pitch. The centre of mass is in front of the centre of buoyancy in the two Nannostomus species which swim with a positive pitch and vice versa in Chilodus punctatus which swims with negative pitch. The relative positions of these two centres are in such a way that they help to bring the fish horizontal during fast swimming. Pitch in these species is maintained by the action of the pectoral and caudal fins. In the two Thayeria species the centre of mass is behind the centre of buoyancy and their separation is responsible for the positive pitch. The fins are used to correct for this pitch to the desirable level. The enlarged lower lobe of the caudal fin in Nannostomus species has an epibatic effect and does not contribute to the forces responsible for the pitch in hovering as previously proposed.
Relative vertebrae size in Nannostomus eques and Nannostomus unifasciatus when compared to Nannostomus becfordi and Nannostomus trifasciatus which swim horizontally show adaptations towards a strategy of rapid start from rest.
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Genre | |
Type | |
Language |
eng
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Date Available |
2010-03-05
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0094639
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.