Sampling Design

• Lecture Outline

– Steps in conducting an investigation

• Assignments

– Read pp. 157 - 218 and 303 - 328 in Fisheries Techniques

Steps in conducting an investigation

1) Sampling justification

2) Review of literature

3) Assess the environment

4) Obtain necessary permits

5) Sample the biota

6) Evaluate catch and harvest

7) Evaluate sample size

8) What information to collect

9) Analyze the data

10) Communicate the results

Sampling Justification

1) Define the questions

a) Null hypothesis

b) Alternative hypothesis

2) Public concern

3) Lack of knowledge

4) Attainable goals

5) Cost benefit analysis

Literature Review

1) Background information

a) Water body

b) Organisms

c) Methods

2) Sources of data and reliability

a) Peer-reviewed journals (Highly reliable)

b) Agency reports (Variable)

c) Personnel communications (Variable)

d) Internet (Variable)

Assess the environment

1) Historic records of water body

a) Flow – U.S. Geological Survey

b) Water level - Army COE

c) Weather – State weather station, NOAA

2) Current conditions

a) Temperature

b) Dissolved oxygen

c) pH

d) Conductivity

e) Turbidity

Obtain necessary permits

1) State collecting permit

2) Federal permit

3) Tribal permits

4) Private landowner permission

5) Institutional Animal Care and Use Committee (IACUC)

a) Required to do research on vertebrate animals in federally funded universities

KSU web page for IACUC

http://www.ksu.edu/research/animal/iacuc/

What information to collect?

1) What is necessary to achieve your goals?

2) What aspects of the ecosystem to monitor?

3) Develop a management plan

Example plan for NFA (Victoria) Freshwater Fisheries Management Policy

http://www.nativefish.asn.au/fwpolicy.html

Sample the biota

1) Gear selection

a) What type of habitat will you sample

b) Which species are you targeting

c) What type of gears were previously used

2) Time of year

3) Duration of study

Sampling designs

1) Simple random

2) Stratified random

3) Systematic

4) Cluster

Evaluate catch and harvest

1) Creel surveys

a) Who to target

b) What information to ask

i) Attitudes

ii) Economics

iii) Effort

Evaluate sample size

1) Power analysis

a) Power = (1 - $)

i) Probability of rejecting the null hypothesis when it is false and the alternative hypothesis is correct

b) Influenced by

i) Sample size

ii) Difference between samples

iii) Precision of samples (variance)

c) How many samples do you need?

Power analysis calculators

http://calculators.stat.ucla.edu/powercalc/

Analyze data

1) Data management

2) Which statistical procedures?

a) Determined a priori

3) Graph data

4) If possible, analyze data in field

Communicate results

1) Presentation at scientific meeting (get input from peers)

2) Agency report (required)

3) Public address, non-scientific literature (Inform resource users)

4) Web-site (Easy access)

5) Peer-reviewed publication (preferred, archived record)