There is no one better than fishes to represent efficient swimming, with an evolution and an adaptation of 500 million years [9]. Although, it should be noted that not all adaptations through centuries were driven by the purpose of swimming only, like wide nose of hammer head shark. Other key factors such as foraging, protection against predators were also involved. Still, fishes are the most efficient swimmers.
Their locomotion involves complex fluid-structure interactions that use various fins and morphological features (see Fig. ??). A fish swims by expansion and contraction of their complex network of skeletal muscle blocks, known as myomeres [10, 11], which drive the body and fin undulations. They are commonly zig-zag, "W" or "V"-
shaped.
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This mechanism can be visualize by the heaving and pitching of the swimming surface, hydrofoils or fins [36–39].
Based upon physiological mechanics, swimming modes can generally be divided into two basic groups. These are termed as Body and Caudal Fin (BCF) and Median and or Paired Fin (MPF) propulsion [40].
1.1.1 Body and caudal fin swimming
Body and Caudal Fin swimming (BCF) uses body undulations towards the caudal fin (tail), tail may also undulate, thus propelling the fish. Almost 88% of the fishes use BCF propulsion [41, 42]. The BCF mode of locomotion is further divided into five categories based upon the fraction of their body that is displaced during propulsion:
(1) Anguilliform, (2) Carangiform, (3) Sub-carangiform (4) Thunniform and
(5) Ostraciiform (Fig. ??).
Irrespective of the thrust generation mechanism, the wake structure of fish swimming is charaterized by the formation of reverse Bénard Von Kármán (BVK)
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A simple 2D schematic of Bénard Von Kármán vortex street behind a 2D cylinder and reverse Bénard Von Kármán (rBVK) vortex street behind a 2D fish in a steady swimming is illustrated in Fig. ??(a and c). For a 2D cylinder, there is a net momemtum or velocity deficit in the wake ( see Fig. ??(b)). Where as for a 2D fish, there is a velocity excess or momentum gain. When a fish is in steady swimming, no net drag nor thrust is exerted on average basis ( see Fig. ??(d)) . However for a crusing fish, the wake has to provide excess thrust on average basis. It should be noted that the acutual wake of a swimming fish is 3D, far more complex and disorganized as compared to organized vortices of a 2D swimmer. Therefore, Fig. ?? is merely a respresentation of differences in the wake structure of a bluff body and a swimmer in a broader and simplistic sense but it is not an actual representation.
In anguilliform mode, the whole body participates in large amplitude of undulation.
The body contains at least one complete wavelength of oscillation e.g. eels.
Müller et al. [29] and Tytell et al. [30] reported that anguilliform swimmers shed two vortices per half tail-beat cycle, which is self-organized into two distinct rows
wave to form, the surging tide must meet an obstacle. When the ocean meets the
They just forgot to mention the other effects of fluids in nature. “The influence of the fluid on a body moving through it depends not only on the body’s velocity but also on the velocity of the fluid,” this is called relative velocity ( ). The relative velocity of a body in a fluid has an effect on the magnitude of the acting forces. For example, as a long distance runner is running into a head wind, the force of the fluid is very strong. If the runner is running with the help of a tail wind, the current’s force is reduced and may even be unnoticeable.
They found that their groupings of similar shaped pelvic girdles fell into the correct category, except at the family level.
Drag is caused by the disrupted air immediately behind an object moving through fluid/air. It acts perpendicular to and in the opposite direction of travel of the object and impedes the motion of the object. It would make sense that if the drag is minimized, the object will travel farther. Lift or curve in the motion of an object through air is a phenomenon that is noticeable in a ball traveling through fluid/air. This change in direction is due to the effect that spin has on the object in motion.
The anal fin is situated between the anus and the tail fin, on the ventral surface of the fish. In Rainbow trout, the anal fin is bordered by a black margin. This is one of the fish’s features which help to identify it. Its function is to stabilise the fish whilst it’s swimming. Due to the dorsal fins being located above the rolling axis of the Rainbow trout, the movement of the dorsal fins would cause the fish to roll whilst swimming if not for the anal fin which counteracts this movement and stabilises the fish. (Journal of experimental Biology).
...n. When a sting ray swims past you or a jelly fish is there in the water beside you, again there is a realization of just how much is going on under the water that is not seen. The waves can make you feel so insignificant when you get tumbled head over heels in the water and you have no control over yourself. Only after experiencing this can the powerfulness of the waves be realized.
In swimming you turn direction when you get to the end of a swimming pool, for freestyle and backstroke you use a tumble turn to change. direction, in butterfly and breathstroke you have to touch the wall with two hands and push off the wall with your feet. Again, speed is only really important in hockey and football. In swimming. There are two types of course, short course and long course.
With smiles on our faces we cast our wisely selected lures into the ocean, but we then encountered our first problem of saltwater fishing. Our lures wouldn’t sink. As soon as they hit the water, the ocean current would just buoy them to the surface and, soon after, down current into the line of a nearby fisherman. Improvising our rigs, we dug the heaviest weights out of our tackle boxes and clamped them onto our lures. Sure enough, we got our lures underwater and under control.
where p is the density of the fluid (in runner’s case: air); v is the velocity of the runner; A is the cross-sectional area perpendicular to the runner’s velocity; and D is the dimensionless quantity called the drag coefficient.
Fishing contains a wide variety of physics. when you cast you are using projectile motion and rotational motion. when you hook a fish it will often use the drag from the current agenst you. Immagine draging a fish through a swift current. You deal with the tention of your line, and the friction of the line through the guides. you also deal with friction when you use a drag.
The catfish maintains an advantage over most fish due to its ability to walk on land. This helpful adaptation comes from the pectoral spines which they flex in order to contour to their body in a walking motion. While the adaptation for land walking is impressive the ability to breathe on land is also beneficial. This ability comes from the hills of the fish which have “highly vascularized arborescent organs that act like accessory breathing structures” (Masterson 2007). Their gas bladder is also minimized to allow for stiffening so that the fish do not collapse on the land (Masterson 2007). Along with the voracious appetite of the fish they have other adaptations that make them invasive as well. The fish can survive in waters that most fish cannot such as hypoxic waters or muddy ponds. Along with being nocturnal these survival abilities allow them to invade aquaculture farms and take prey on the fish stock
On a more scientific note I am interested in mechanics of fluids. This interest was enforced last year when I had the opportunity to attend a lecture on fluid mechanics at P&G. At the conference I greatly expanded my knowledge regarding the physical aspect of fluids and their properties. In last year's AS course we have met a topic in this field. I will be applying ideas and knowledge gathered from last year for this investigation.
Basic body plan and body axes are established. Three embryonic axes are formed i.e. dorsal-ventral, posterior-anterior and left-right.
Fishing has been used for ages for many things like food, sport, and just for amusement of the chase; because of this, many different techniques have been developed from the centuries fishing been constructed. Also fishing can be a purpose for life just like what Henry David Thoreau said “Many men go fishing all of their lives without knowing that it is not fish they are after”. Everyone has issues in their life and fishing can help with it in many forms. Over all the years love of fishing has grown and, many different types have emerged such as fly-fishing, saltwater, and freshwater fishing. Also there are many different styles of fishing to the different types from baits to the rod. Because, of the constant demand and love for fishing, salt water fishing has become a growing industry along the coast of America, and saltwater fishing provide a recreational sport for many, but it can require boat access and the correct license and fishing equipment.