Fish "Stress"

1. Fish "Stress"

2. These fish are more likely to get sick then fish that remain in the pond… Why?

3. Largemouth Bass Tournaments

4. Why did the bass get sick?

5. Why don’t the fish grow larger?

6. The fish are making some sacrifices to survive sub-optimal situations

7. pH 7.4 Temp 21 C Hardness 75 ppm Oxygen 8 ppm Food, abundant Growth Reproduction Healthy

8. pH 7.4 Temp 21 C Hardness 75 ppm Oxygen 8 ppm Food, abundant Growth Reproduction Health 18 C

9. pH 7.4 Temp 21 C Hardness 75 ppm Oxygen 8 ppm Food, Scarce Sick Growth Health 5 C Or Dead

10. How do the fish make these adjustments?

11. Fish use their brains and endocrine systems (hormones) to adapt to changes in their environment

12. Small changes mean small adjustments and minor sacrifices No Sweat

13. Bigger changes mean bigger adjustments and bigger sacrifices Yikes

14. Extreme changes or rapid changes can exceed the fish’s ability to adapt #&$!!

15. BassTournament • Bass had to adapt to… • muscle fatigue • skin damage • puncture wound • temperature changes • poor water quality • crowding • Some things had to be let go • One of them was immunity

16. TheAquarium • The fish had to adapt to • Poor water quality • Social competition • Photoperiod disruption • Poor food quality • The fish spent energy to deal with all of those problems • There wasn’t enough energy left to support growth and reproduction

17. Summary • Fish adjust their behavior and biochemistry to do the best that they can under the conditions • If conditions are good, they will grow and reproduce • If conditions are poor, they may have to spend all of the energy just to survive • If things are really bad, they may not be able to adapt and will die

18. Hormones ! How Do Fish Make All The Needed Adjustments To Their Systems?

19. Fish Hormones Adapting to Sudden Emergencies

20. HK Adrenalin

21. Brain Nerve Cardinal Vein Chromaffin Cells Head Kidney

22. Brain Head Kidney Trunk Kidney Muscle Gills Swim Bladder Liver Spleen Heart Intestine

23. Increases heart rate • Increases breathing (respiration) rate • Opens gill circulatory system • Open muscle circulation • Decreases blood to guts • Releases sugar from liver

24. The Beneficial effects of epinephrine/adrenaline are…

25. Better “fight or flight” capabilities

27. Acute Emergency = Epinephrine

28. Fish Hormones Adapting to “Slow” Emergencies

29. Starvation • Entrapment • Injury • Social problems

30. Interrenal cells Lateral Line Liver Nares… Pituitary HK

31. Nerves Connecting Brain to Pituitary Hormone-Secreting Cells

32. Brain HK Cortisol Interrenal Cells ACTH Adrenocorticotropic Hormone

33. Brain: Perception of a stressful situation Nerves carry signal to pituitary Pituitary: Secretion of ACTH Blood carries ACTH to kidney Head Kidney: Secretion of Cortisol Kidney secrets cortisol into blood Other Organs: Respond to cortisol

34. Effects of Cortisol • Protein catabolism • Breaks down protein for energy

35. Stress response hormones help fish adapt

36. Acute Emergency Epinephrine Increases oxygen and fuel to muscles Fight or flight Slow emergency Cortisol Releases stored energy Stress Response

37. So why don't they make epinephrine and cortisol all the time?

38. There is no such thing as a free lunch !

39. Stress • Fish must adapt to changes • Small changes good conditions= Great • Bigger changes or poorer condition = Trouble • Too big, bad conditions = Dead • Epinephrine • Fight or flight • More oxygen and energy to muscles • Nerves from brain signal chromaffin cells in HK QUIZ • Cortisol • Slower emergencies that limit food availability • Energy from protein • Brain- nerves - pituitary – ACTH – Interrenal cells in HK