Quiz 6

Question 1

Unique aspects of stocks

Answer 1

• life history characteristics
• demographics
• morphology
• genetic distribution

Question 2

Was is a fish stock

Answer 2

-a group of fish that is distinct in space or time

Question 3

Natural marks for stock discrimination

Answer 3

• naturally occuring differences
• includes morphology pattern, coloration, life-histor, chemistry
• all fish get tagged

Question 4

Artificial marks for stock discrimination

Answer 4

• conventional/electronic/chemical tags
• individual fish require tagging
• mark/recapture issues

Question 5

Stock discrimination

Answer 5

-the ability to recognise a group of fish as separate groups

Question 6

Assumptions to natural marks

Answer 6

• marks are characteristic and reproductible
• all groups contributing to group mixing are classified
• the mark is stable

Question 7

Genetic analysis with nuclear material

Answer 7

• allozymes
• microsatellite markers
• mitochondrial DNA

Question 8

Microsatellite markers

Answer 8

• much more diverse

- provides info about population structure, migration/dispersal

Question 9

Mitochondrial DNA

Answer 9

-good for evolutionary applications, especially rapid evolution

Question 10

Gel electrophoresis

Answer 10

• sorts DNA fragments according to length

- DNA visualized by staining and illuminating under UV light

Question 11

Unit stock is a discrete group of individuals:

Answer 11

• from the same gene pool
• self-perpetuating
• fished and managed as a stock

Question 12

Different methods of sampling

Answer 12

• uniform
• random
• aggregated
• gradient

Question 13

How to get an unbiased estimate of population

Answer 13

-stratifying sampling effort

Question 14

Different ways to estimate abundance

Answer 14

• direct estimates (visual counts
• hydroacoustic surveys
• indirect estimates (calculations)

Question 15

CPUE

Answer 15

• catch per unit of effort
• used for long-term monitering
• important to standardize effort

Question 16

passive vs active gear

Answer 16

• passive: trap nets - organisms wander in

- active: trawliing or seining

Question 17

swept area method

Answer 17

vol swept = (size of net opening) * speed * duration

Question 18

Mark-recapture method

Answer 18

• collect fish under assumption of the unit stock

- mark fish, return them so they can mix evenly back into pop

Question 19

Peterson method

Answer 19

-estimates pop abundance
N(hat) = (MC)/R
M = # of fish marked
N = total # of fish in pop
C = # of fish collected 2nd time
R  = # of recaptures
-error occurs when R = 0

Question 20

Bailey’s method

Answer 20

-used when pop abundance sampling with replacement

= (M(C+1))/(R+1)

Question 21

Chapmans method

Answer 21

-sampling for pop abundace is done without replacement

=(((M+1)(C+1))/(R+1)) + 1

Question 22

Why would we do repeated marking techniques

Answer 22

-to avoid being biased towards N

Question 23

How can marked fish dissapear

Answer 23

• mark retention is poor
• fish are trap-shy
• difficult to recognize marked fish
• immigration and death

Question 24

Schnabel estimator

Answer 24

= sum(CM)/sum(R)