The fish fauna of Antarctic waters are dominated by the suborder Notothenioidei, both in species number and biomass (Eastman, 1993). Within this suborder there are seven families composed of 120 species, representing nearly 35 % of the total number of fish species living in the Southern Ocean. Most...
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.608.9164 http://jeb.biologists.org/content/206/2/411.full.pdf |
| Summary: | The fish fauna of Antarctic waters are dominated by the suborder Notothenioidei, both in species number and biomass (Eastman, 1993). Within this suborder there are seven families composed of 120 species, representing nearly 35 % of the total number of fish species living in the Southern Ocean. Most notothenioids are demersal fishes and all use a labriform style of swimming powered by large pectoral fins, a ubiquitous form of locomotion presumably because the ancestral notothenioid stock used this swimming style (Eastman, 1993). In general, Antarctic fishes are not particularly active and swim at approximately 1–2 SL s–1, while many species spend large amounts of time resting on pelvic and anal fins on the substrate (Montgomery and Macdonald, 1984; Archer and Johnston, 1989). Labriform sculling provides a high degree of maneuverability and may be the most efficient form of swimming at these slow speeds (Blake, 1979), possibly conferring a selective advantage at cold temperatures. Although notothenioids tend to have reduced axial muscles compared to temperate species, some do employ sub-carangiform swimming powered by glycolytic axial muscle at higher swimming speeds (4–5 SL s–1) (Montgomery and Macdonald, 1984; Archer and Johnston, 1989). Notothenioids also have a small amount of oxidative myotomal muscle that provides direction during swimming (Archer and Johnston, 1989). There are two types of labriform swimming: drag-based and lift-based. Pectoral fins move perpendicular to the flow during the power stroke of drag-based swimming, while in lift-based swimming, fins move up and down like bird wings (Lindsey, 1978). Notothenioids employ drag-based labriform locomotion, controlled by six muscles of the pectoral fin (Johnston, 1989). The power stroke is produced by the |
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