Fish Locomotion

1. Fish Locomotion Locomotion is the result of interactions between the fish’s body shape, anatomy, physiology, behavior, and the behavior of water

2. Properties of water that determine efficiencies and constraints in locomotion • cohesion • adhesion • density • incompressibility • viscosity • O2 solubility • ionic solubility • specific heat • light transmission • others

3. Cohesion • Attraction between particles of the same substance • Water molecules bind to each other with hydrogen bonds • Surface tension, a measure of the strength of water’s cohesion, prevents penetration of water mass by solid macroscopic objects • e.g. guy below is about to feel some resistance, ala surface tension, to his entry into the water • Many objects rest on water surface due to surface tension resisting disruption • e.g. whirligigs, water strider, many insect larvae and exuviae

4. Many water properties are temperature-dependent • Surface tension of water decreases significantly with temperature. • Hot water is better than cold for cleaning because lower surface tension makes hot water a better "wetting agent" (lower cohesion/adhesion ratio)

5. Adhesion • Attraction between two different substances. • Water will make hydrogen bonds with other surfaces (e.g. glass, soil, organic tissues> • Capillary action • Turbidity from suspended anion-rich particles like clay molecules

6. Viscosity Viscosity (resistance to change in form) — honey drops in slowly deforming (stretched out) drops breaking away from larger fluid mass — water drops in somewhat deforming drops breaking away from larger fluid mass — mercury drops in globular drops breaking away from larger fluid mass — viscosity decreases with temperature Compressibility — water is relatively incompressible — 50 times greater than air Density — 800x more dense than air • hydrogen bonds Movement is more energetically expensive due to the above properties

7. Drag • Skin (friction) drag —results from water sticking to fish as it tries to move through the fluid —more surface area means more water sticking to object • Form (pressure) drag —results from positive pressure upstream of object and negative pressure behind —less streamlined objects prone to generating more pressure in flow FYI. Drag depends on the properties of the fluid and on the size, shape, and speed of the object, often expressed using the drag equation FD = ½ ρv²CDA where FD is the drag force, ρ is the fluid density, v is the velocity differential between the fluid and object, CD is the drag coefficient, and A is the cross sectional area of the object normal to flow. CD depends on object shape and Reynolds number, Re = (vD)/ν, where D is a characteristic linear dimension (e.g. diameter of sphere) and  ν (Greek nu) is the kinematic viscosity of the fluid, equal to the viscosityμ divided by fluid density.

8. Reduction of drag • Minimize the amount and magnitude of water displacement • Two ways fish can reduce these • Pressure: more streamlined, like a javelin (but more skin drag due to increased surface area) • Skin (friction) drag: reduce surface area, like a sphere, or friction per unit area (like a greased pig). The former increases pressure drag, but some shapes have better properties (see examples at right). Friction can be reduced by coatings (like mucus) or textures that promote turbulent flow near body (like dimpled golfballs).

9. What is the optimal body shape for fish?

10. Webb’s functional morphology plane accelerators cruisers maneuverers

11. acc Acceleration specialists(adaptation for burst swimming) General form • flexible (facilitates C-starts) • torpedo-like – acute triangular snout (reduces buildup of anterior positive pressure) – fusiform (reduces pressure drag—less water displacement) – torpedo-like body profile (reduces pressure drag on glide) Posterior form – long muscular propulsive region (shaded area) (facilitates rearward thrust of large mass of water—C, then S) – posteriorly-placed median fins (leverages thrust) – expansive posterior fins (increases pressure drag for thrust)

12. acc Adaptations for burst speed Flexible, torpedo-like body Posterior-placed median fins (exc. male gonopodium) Ventrally-placed pectoral fin Small pectoral and pelvic fins relative to body size high caudal third body area Gambusia affinis caudal third area gonopodium body shape found in absence of predators predator-associated body shape from Langerhans et al. (2004) Evolution58: 2305

13. man Maneuvering Specialists – Adaptations for structure living Large Fins Relative To Body Size Laterally Compressed Body: Gibbose Fins Evenly Distributed Laterally Positioned Pectoral Fins; large relative to body

14. man What about intraspecific variation regarding maneuverability morphology? • Lentic vs lotic habitats? • Predation?

15. cru Cruisers: Adaptations for roving or current Forked Tail, Narrow or Average Peduncle Fusiform, Streamlined body Relatively large caudal fin Horizontally Positioned Pectoral Fins

16. http://people.tamu.edu/~tdewitt/wfsc448/Disentangling complex phenotype-environment relationships.ppt

17. Other body shapes • Filiform/angilliform • Eel like, borrowing • Dorso-ventrally compressed • Benthic and often in high flow

18. Case studies

21. Body Musculature • Trunk musculature • Myotomes or myomeres - series of muscle blocks • Myosepta - sheets of connective tissue separating myomeres • Myotomes are folded, outer edges resemble a “W”

23. Body Musculature • Trunk musculature • A horizontal septum separates upper and lower muscle masses • 40-60% of fish weight is muculature • Upper muscles are called epaxial muscle • Lower muscles are called hypaxial muscles

24. Chinook Salmon Lamprey/Hagfish

25. thunnid fish other

26. Fish Muscles • 3 types • Red, pink, and white • Most have a combination (2 or 3 types) • What makes the red muscles red? • – supernumerary capillaries Tuna

27. Muscles White muscle – majority of post cranial muscles in most fishes – thicker muscle fibers than red muscle (300m) – lacks myoglobin; little vascularization; limited oxygen supply – energy from anaerobic glycolysis – fatigues quickly – works for short periods of time – quick bursts of movement – produces lactate; requires significant recovery time

28. Muscles Red muscle - thin, lateral, superficial sheet under the skin between the epaxial and hypaxial muscle masses – smaller muscle fibers than white (50 - 150 m) – infused with capillaries (hemoglobin) and has copious myoglobin – rich oxygen supply – used for continuous (aerobic) swimming – abundant, large mitochondria – energy supplied by aerobic oxidation of lipids – fast recovery of muscles

29. Red Muscle Red: by cross-section, 5 to 15 % muscle mass in most species (some species 0 % while others + 15 %)

30. The Tuna: A Swimming Machine • Never stop swimming • Cover vast distances • 7,000 miles! • Northern bluefin cross Atlantic in 119 days (40 miles/day) • Endurance swimmers • Capable of high speed bursts • It’s all about the adaptations . . .

31. Muscles • Pink muscle - contains fibers intermediate in character between those of white and red muscle • Used at intermediate swimming velocities • Too high for red muscle to sustain but too low for effective use of white muscle • Aerobic • Mosaic muscles - salmonids have red and pink muscle fibers mixed with white fibers • Used by smolts during migration to sea

32. Red Muscle vs. White Muscle Red White

33. Moving Through Water • Functions of Fins • Caudal fin: propulsion (oscillatory and undulatory), rudder • Dorsal and anal fins: undulatory propulsion and prevents roll • Pelvic fins: controls pitch • Pectoral fins: propulsion (sculling) and control yaw; also control turning and brakes

34. Moving Through WaterBody/Caudal Fin (BCF) Locomotion Oscillation = flapping motion Undulation = waves passing down body or fin

35. Modes of locomtion • Propulsion by body and/or caudal fin • Propulsion by undulation of median or pectoral fins • Propulsion by undulation of median or pectoral fins • Non-swimming locomotion

36. Fish LocomotionCarangiform

38. Moving Through Water • Body/Caudal Fin (BCF) Locomotion • Anguilliform • Large side-to-side amplitude of the wave along the whole body • Purely undulatory, most of the body participates

39. Moving Through Water • Body/Caudal Fin (BCF) Locomotion • Subcarangiform • Similar to anguilliform • Posterior half of the body • Anterior portion of the body often rounded or thick • Anterior portion low flexibility • Posterior undulations • Caudal fin rounded, truncate, or emarginate • Trout, cods, basses

40. Moving Through Water • Body/Caudal Fin (BCF) Locomotion • Carangiform • Posterior body flexes • Anterior 1/2 or 2/3 body inflexible • Narrow caudal peduncle • Posterior portion of body tapers • Caudal fin forked or lunate=(half moon) • High aspect ratio • Herrings, sardines, some jacks and some mackerals

41. Moving Through Water • Body/Caudal Fin (BCF) Locomotion • Thunniform • Most efficient locomotion mode (but few species) • High cruising speeds to be maintained for long periods. • Significant lateral movements occur only at the caudal fin and area near the narrow peduncle • Stiff caudal fins • Aspect ratio (4-10)! • Marlins, sailfishes, Lamnid sharks, tunas

42. Moving Through Water • Body/Caudal Fin (BCF) Locomotion • Ostraciform • Oscillation of the caudal fin • Assisted with pectoral fins

43. Moving Through Water • Median/Paired Fin (MPF) Locomotion • Diodontiform: achieved by passing undulations down broad pectoral fins • Amiiform: done by undulations of a (usually long-based) dorsal fin, while the body axis is often held straight when swimming • Gymnotiform: propulsion is by undulations of a long-based anal fin • Balistiform: both the anal and dorsal fins undulate to generate the propulsion forces

44. Modes of Swimming

46. Aspect ratio tail height:tail depth High AR = efficiency, speed large thrust w/ low drag Low AR

47. Fins

48. Bernal et al. 2001

49. Off-plane locomotory paradigms?

50. Non-swimming Locomotion • Jet propulsion - water exhaled from the gill chambers; anglerfishes • Terrestrial locomotion - fish can employ anguilliform motion over land • Walking- batfishes • Burrowing - eels, mudminnows • Jumping - tarpon, manta rays • Gliding - flying fish • Flying- freshwater hatchetfishes, freshwater butterflyfish