Fish biomechanics and locomotion - Part 3

Question 1

Each fin ray is called a ________, it is made up of two bony halves called ________.

Answer 1

lepidotrich
hemitrich(s)

Question 2

_________ are under muscular control

Answer 2

Hemitrichia

Question 3

In actinopterygii, every fin ray has ____ parts. _____ and _____ parts.

Answer 3

two

left and right parts

Question 4

Each fin ray has a small _____ attached to it, on the left and right.

Answer 4

muscle

Question 5

In ray finned fish, each ray can be __________ controlled.

Answer 5

independently

Question 6

Fin rays allow for ______-______ control of swimming

Answer 6

fine-scaled

Question 7

What are the benefits of fins rays?

Answer 7

Fine scale control of direction without changing which trunk muscles are used.
Can still swim fast.

Question 8

What are the evolutionary trends in locomotion?

Answer 8

Pectoral fins become larger and at a greater angle.

Dorsal fins become doubled and anal fin becomes larger.

Question 9

Much of the evolution in fish swimming modes has been on the ______ rather than on the _______.

Answer 9

fins

trunk

Question 10

What were the two things that happened evolutionarily, especially in teleost, for swimming modes.
Explain why.

Answer 10

1 - Pectoral fins got bigger and are attached to the body at a greater angle

• bigger = can push more water
• greater angle and position = more fine scale control of movement

2 - Dorsal and anal fins got bigger and two dorsal fins

• partly to break up turbulent wakes
• more fine scaled control of swimming

Question 11

Sharks will change _______ of ______ as flow speed changes to provide lift.

Answer 11

Angle of attack

Question 12

_______ ______ can be used to affect position in the water column

Answer 12

Body position

Question 13

What is a way to save energy while swimming?

Answer 13

Lift

Question 14

If a shark wants to go up, how will he change his angle of attack?
Go down?

Answer 14

If want more lift, angle more relative to the water column, this will cause more negative pressure on the top, causing lift and the shark to rise.
Change angle to opposite direction.

Question 15

Cost of swimming depends on fish _____, _____, ________ of water, and ______ ______.

Answer 15

Fish size
fish shape
temperature of water
swimming mode

Question 16

What does cost of swimming depend on?

Answer 16

Fish size
fish shape
temperature of water
swimming mode

Question 17

How does shape affect swimming cost?

Answer 17

More streamlined = save energy

Question 18

How does size affect swimming cost?

Answer 18

Bigger fish = cost more

Question 19

How does temperature affect swimming cost?

Answer 19

Mostly affects metabolism and viscosity, generally negligible.
Although, there is an optimal temperature for species to minimize energy use.

Question 20

Draw the graph for metabolic cost of swimming speed for pelagic fish.

Answer 20

Oxygen consumption on y, swimming speed on x.
At slow speeds - more costly than intermediate speeds
at high speeds - more costly than intermediate speeds
U-shaped graph - costs more at extremes

Question 21

Explain the metabolic cost for swimming speed graph in metabolic fish.

Answer 21

At slower speed, reduced lift, have to use fins to keep themselves up.
At higher speeds, metabolically taxing.

Question 22

What are different ways fish can counteract the costs of swimming.

Answer 22

Fish will often swim in a middle zone for speed, where metabolic costs are lower.
Stick to narrow range of swimming speeds and will stay there if nothing else changes.