midterm

Question 1

list three factors that cause newly buttoned up fry to be smaller than expected

Answer 1

• frequent disturbance
• light exposure
• excess flow
• low oxygen
• sudden temperature change
• high ammonia
• supersaturation
• no substrate

Question 2

what does the acronym MAWW stand for?

Answer 2

maximum alevin wet weight

Question 3

What is the name of the following equation and what does it predict?

ATU = T a/(T-c)b

Answer 3

Belehradiek model

ATUs until MAWW

Question 4

What is the relationship between salmonid egg size and the time to button up?

Answer 4

The larger the egg, the longer it will take to button up

Question 5

List three suitable methods of conducting an inventory assessment on a stock of month old salmonid fry

Answer 5

a) weight
b) electric counter
c) volume

Question 6

In the following weight/length equation, what is the value of ‘b’ for salmonids?

W = aLb

Answer 6

(isometric growth)

b= 3

Question 7

List 2 factors which may cause a tank of salmon to have a highly variable condition factor.

Answer 7

a) unequal water quality
b) poor feedings
- poor circulation
- parasites/desease
- time to grade

Question 8

Draw a graph with properly labeled axes to illustrate the relationship between food consumption (as a percent of body weight per day) in salmonids and fish size

Answer 8

Draw This Seperately. DO IT

Question 9

What might you observe that would indicate the flow rate in a circular tank was too great?

Answer 9

the fish are trying to swim but don’t move forward

Question 10

List four factors which may cause a variation in the ration level consumed by a stock of salmonids compared to that predicted by a feed table

Answer 10

• feeding frequency
• season
• time of day
• oxygen concentration
• stress and disease

Question 11

Describe how a down hole or U-tube oxygenation device operates

Answer 11

oxygen and water at top, pressure at the bottom increases the dissolution

Question 12

Use a figure to illustrate a crowding device that would be suitable for use in a large circular salmonid tank

Answer 12

DRAW IT

Question 13

What effect does inflow water pressure have on water quality in a circular fish tank equipped with a spray bar?

Answer 13

• it oxygenates the water and increases the flow

- controls re-aeration and adds oxygen

Question 14

Where are the outlet screens located in a Burrow’s pond?

Answer 14

DRAW IT

Question 15

Use an illustration to show the components and their arrangement of a fish proof outflow for a large raceway using a screen, dam boards and a fixed baffle to resuspend fines

Answer 15

DRAW THIS TOO

Question 16

Explain what is meant by the expression ‘plug flow’ and name the salmonid rearing container type it occurs in.

Answer 16

Def: enters one end, exits the other with minimal mixing

Container Type: raceways and troughs

Question 17

What is a ‘Polar Cirkl’ net pen frame constructed of?

Answer 17

plastic pipe (foam filled polyethyline)

Question 18

In what situation would a single point anchoring system be best for a salmonid net pen?

Answer 18

lakes

Question 19

What is the weight of 9000 meters of 210 denier webbing yarn?

Answer 19

1 denier = 1 g. 210 grams

Question 20

In a marine salmonid net pen system there are usually two concentric rings or squares of floats surrounding the sea cages. What is the purpose of the outer and inner sets of floats?

Answer 20

• Outer: navigation markers

- Inner: Shock absorption

Question 21

List the Davis B oxygen protection levels (mg/L) for the following life history stages of salmonids

A: salmonids in seawater
B: salmonids in freshwater

Answer 21

A: 7ppm
B: 6ppm

Question 22

Use a graph with properly labeled axes to illustrate the relationship between oxygen consumption rate of salmonids and ambient oxygen concentration. Indicate the incipient limiting oxygen tension, the incipient lethal oxygen tension, and the standard metabolic rate.

Answer 22

Graph it, yo.

Question 23

What would be a suitable maximum stocking density for 6 inch rainbow trout, in units of pounds of fish per cubic foot of water?

Answer 23

3lb/ft cubed

Question 24

Given a flow index of 0.2, what would be a suitable flow rate of oxygen saturated water to support 100kg of 12 cm coho salmon at 12 C in a 3 meter diameter circular tank?

Answer 24

W= FLI
I= W/FL
100kg = (0.2)(12)(x)
100kg/(0.2)(12) = x
x= 41.66 LPM

Question 25

Use a graph with properly labled axes to illustrate the relationship between flow index and water temperature for a given rearing container

Answer 25

GRAPH

Question 26

Approximately how much oxygen is consumed by salmonids for each kilogram of food they consume?

Answer 26

300 g/kg