These fish are more likely to get sick then fish that remain in the pond…
Largemouth Bass Tournaments
Why did the bass get sick?
Why don’t the fish grow larger?
The fish are making some sacrifices to survive sub-optimal situations
pH 7.4 Temp 21 C Hardness 75 ppm Oxygen 8 ppm Food, abundant Growth Reproduction Healthy
pH 7.4 Temp 21 C Hardness 75 ppm Oxygen 8 ppm Food, abundant Growth Reproduction Health 18 C
pH 7.4 Temp 21 C Hardness 75 ppm Oxygen 8 ppm Food, Scarce Growth Health 5 C Sick Or Dead
How do the fish make these adjustments?
Fish use their brains and endocrine systems (hormones) to adapt to changes in their environment
Small changes mean small adjustments and minor sacrifices No Sweat
Bigger changes mean bigger adjustments and bigger sacrifices Yikes
Extreme changes or rapid changes can exceed the fish’s ability to adapt #&$! !
Bass Tournament 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
The Aquarium 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
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
How Do Fish Make All The Needed Adjustments To Their Systems?
Fish Hormones Adapting to Sudden Emergencies
HK Adrenalin
Head Kidney Cardinal Vein Chromaffin Cells Brain Nerve
Gills Heart Liver Intestine Spleen Swim Bladder Brain Muscle Head Kidney Trunk Kidney
Increases heart rateIncreases heart rate Increases breathing (respiration) rateIncreases breathing (respiration) rate Opens gill circulatory systemOpens gill circulatory system Open muscle circulationOpen muscle circulation Decreases blood to gutsDecreases blood to guts Releases sugar from liverReleases sugar from liver
The Beneficial effects of epinephrine/adrenaline are…
Better “fight or flight” capabilities
Acute Emergency = Epinephrine
Fish Hormones Adapting to “Slow” Emergencies
Starvation Entrapment Injury Social problems
HK Lateral Line Liver Nares… Pituitary Interrenalcells
Nerves Connecting Brain to Pituitary Hormone-Secreting Cells
Brain HK Interrenal Cells ACTH Adrenocorticotropic Hormone Cortisol
Brain: Perception of a stressful situation Pituitary: Secretion of ACTH Head Kidney: Secretion of Cortisol Other Organs: Respond to cortisol Nerves carry signal to pituitary Blood carries ACTH to kidney Kidney secrets cortisol into blood
Effects of Cortisol Protein catabolism –Breaks down protein for energy
Stress Response Acute Emergency Epinephrine Increases oxygen and fuel to muscles Fight or flight Slow emergency Cortisol Releases stored energy
There is no such thing as a free lunch !
Stress Fish must adapt to changes Small changes good conditions= Great Bigger changes or poorer condition = Trouble Too big, bad conditions = Dead 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 Epinephrine Fight or flight More oxygen and energy to muscles Nerves from brain signal chromaffin cells in HK Cortisol Slower emergencies that limit food availability Energy from protein Brain- nerves - pituitary – ACTH – Interrenal cells in HK Cortisol Slower emergencies that limit food availability Energy from protein Brain- nerves - pituitary – ACTH – Interrenal cells in HK