1. Fish Marking Not in your textbook!

2. Reasons for marking fishes n To identify stocks n To assess stock size n To assess growth and mortality rates Mark must have minimum interference with biology of fish while having maximum utility

3. Requirements of the mark n 1) persist for life of fish n 2) not interfere with behavior n 3) not make fish more vulnerable to predators n 4) not tangle with weeds or nets n 5) easy to apply (minimize equipment, stress to fish) n 6) applicable to broad range of sizes

4. More requirements n 7) variable to allow distinctive marking of groups n 8) not create health hazard n 9) easily detected in field by untrained people n 10) inexpensive, easy to obtain n 11) minimum confusion in reporting n 12) remain unaffected by preservatives n 13) no effect on growth or survival of fish

5. Selection considerations n 1) length of time n 2) skill of personnel – uniform application, minimum disturbance n 3) species to be tagged n 4) means of recovery – commercial or sport fishery (incentive) n 5) concurrent marking programs

6. Types of marks n 1) tags n 2) fin clipping n 3) branding n 4) dye n 5) tattooing n 6) subcutaneous injection n 7) genetic

13. Population Dynamics Chapter 6

14. Fish Population Assessments n Direct counts n 1) construct weir/trap system in river n 2) use counting platform n 3) use electrical counting system, hydroacoustics

15. Fish Population Assessments n Direct counts n 1) construct weir/trap system in river

16. Fish Population Assessments n Direct counts n 1) construct weir/trap system in river n 2) use counting platform

17. Fish Population Assessments n Direct counts n 1) construct weir/trap system in river n 2) use counting platform

18. Fish Population Assessments n Direct counts n 1) construct weir/trap system in river n 2) use counting platform

19. Fish Population Assessments n Direct counts n 1) construct weir/trap system in river n 2) use counting platform

20. Fish Population Assessments n Direct counts n 1) construct weir/trap system in river n 2) use counting platform n 3) use electrical counting system, hydroacoustics

21. Fish Population Assessments n Direct counts n 1) construct weir/trap system in river n 2) use counting platform n 3) use electrical counting system, hydroacoustics

22. Fish Population Assessments n Indirect counts - population estimates n 1) plot method n 2) mark & recapture - Peterson method n 3) mark & recapture - Schnabel method n 4) change in ratio or dichotomy method n 5) removal sampling - Zippin method