Topic 4: Shark Physiology 2 (Stress Response) Flashcards
(128 cards)
1
Q
Where is the Atlantic Sharpnose shark commonly found? Habitat?
A
- Order: Carcharhiniformes
L> Family: Carcharhinidae - warm temperate water
- common down the coast of Maine and the gulf of Mexico…its caught frequently in long line fishing
2
Q
Where is the sharp nose shark a year round resident?
A
- off the shout of South Carolina, Florida and the Florida Keys.
3
Q
What kinds of migration does the sharp nose shark do?
A
- inshore to offshore migrations
* migrate with the warmer waters up north
4
Q
What does the sharp nose shark form during migrations?
A
- large sexually segregated schools
5
Q
As winter approaches, where do sharp nose sharks go?
L> what about in the spring?
A
- move off shore into deeper water
L> they return inshore to mate in spring and give birth after 10-11 month gestation period.
6
Q
What depths are the sharp nose sharks commonly found?
A
- up to 920 feet (280m) but they mostly remain in waters less than 32 feet (10m) deep.
7
Q
Sharpnose sharks are common residents of the surf zone, the Atlantic sharp nose however has been found where?
A
- estuaries and harbours
8
Q
Although the sharp nose shark is able to tolerate lower salinity levels they do not what?
A
- venture into fresh water like the bull shark ( Carcharhinus leucas)
- it can tolerate changing conditions
9
Q
Sharpnose Sharks:
- Males of this species reach maturity between ___ and __ years of age, at which time they average between __-___ inches (__-__cm) total length.
A
- 2 and 2.4
- 31.5-33.5 inches ( 80-85cm)
10
Q
Sharpnose Sharks:
- Females of this species reach sexual maturity at total lengths between __-__ inches (__-__cm), after __-__ years. Maximum length of the Atlantic sharp nose shark is __ inches (__cm)
A
- 33.5-35.5 inches (85-90cm)
- 2.4-2.8 years
- 43.3 inches (110cm)
11
Q
Sharpnose Sharks:
- maturity level is mostly determined by?
- What sex is largest and why?
A
- size
- females
L> to help with producing offspring…
12
Q
Sharpnose Sharks:
- The longer and bigger the female the more what?
A
- more pups are produced
13
Q
Sharpnose Sharks:
- whats the longest recorded length of this species?
A
1.1m
14
Q
Sharpnose Sharks:
- number of pups vary between - and is related to?
A
- 4-7 pups
- size of the mother ( typical of shark species)
15
Q
Sharpnose Sharks:
- viviparous or oviparous ?
A
- viviparous
L> placental sac.–> nurses offspring
-live young
16
Q
Sharpnose Sharks:
- how do the females of this species differ from other charcharhinids ?
A
- ovaries of the female develop on the left!
17
Q
Sharpnose Sharks:
- At birth, the pups are how long in length? (cm and inches)
A
- 11.4-14.6 inches (29-37cm)
18
Q
Sharpnose Sharks:
- On average, pups grow __inches (_cm) a month during the first three months of life.
A
- 2 inches (5cm)
19
Q
Sharpnose Sharks:
- After the first three months of life what does the growth rate of pups slow down to?
A
- it slows to an average of 0.35 inches (0.9cm) a month during the winter and spring months.
20
Q
Sharpnose Sharks:
- Upon reaching lengths of 24-26 inches (60-65cm) what happens to growth rate in the pups?
L> also at this size what do the sharks begin to form?
A
- it begins a linear increase of 0.5 inches (1.3 cm) a month for approximately a year.
- they begin to form a distinct size class, which separates them from newborns.
21
Q
Sharpnose Sharks:
- At 2ft long what are they classified as? Juvenile or newborns?
A
Juvenile
22
Q
Sharpnose Sharks:
- They have a pretty rapid growth rate as pups but it slows down in the __ and __ months. What is the bonus of having such a rapid growth rate early on?
A
- winter and spring
- good to get them out of the bottom of the food chain!
23
Q
What shark is one of the most common costal shark caught via by catch in shrimp fisheries?
A
- Sharpnose sharks
24
Q
Sharpnose Sharks:
- When they are caught what do fisheries utilize them for?
A
- meat, fins, bait for larger sharks. (especially used when they are pups that are caught!)
25
Sharpnose Sharks:
- What are they listed as by the IUCN?
L> what does IUCN stand for?
- Least concern because they are very plentiful.
| L> International Union for Conservation of Nature
26
International Union for Conservation of Nature
| - what makes them good study subjects for stress response?
- their biology is very well studied!
27
Majority of previous studies on stress response used ___ sharks because they are easy to handle.
small
28
Any large sharks that were studied for stress response how did they measure stress?
L> issues ?
- by taking blood samples more than an hour after initial stress.
L> can not measure onset....there may have been in recovery phase or peaked!
29
In 2001-2 study before the blood sample was taken from the larger sharks how long were they on the line?
- more than an hour
| L> they were also in deep ocean..
30
Why is playing with a caught fish for as long as possible a major concern for recreational fishing?
- if you have ppl coming out and paying for it say... 5-6 ppl sharing a boat to catch a shark land say one rod catches a shark...everyone is expected to get a turn with that shark. So if each person gets a turn for 10mins thats 60 mins total the animal has been stressed out and still fighting ...it was never addressed before until the present study looked at in lecture!
31
What is a massive dilemma for trying to measure stress response initially?
- you cannot because of the pre-catch phase.
| L> the present study's primary goal was to establish this baseline stress response!
32
What are the objectives of the current study?(2)
1. obtain baseline estimates for hematological parameters
| 2. Describe physiological changes
33
What is one of the most blatantly obvious stress signs for a shark?
- If a blotchy pattern is present on the stomach. It is a stress response via blood vessels dilating. Normally the bely should be white. This is the very first sign of stress.
* * a couple minutes should be the limit at which you examine a specimen not long periods of times.
34
In the current study explain the methods. (in general)
1. Used hook and line but the subjects were kept on the line but allowed to swim freely.
2. 5 Blood samples were taken over an hour. The sharks were reeled in slowly and the blood sample was taken every 15 minutes. (0.5ml extracted)
35
In the present study did they record the time of initial catch?
yes
36
What is the downside to leaving the shark on the line even if they are able to swim freely?
- the animal is still being stressed out
| L> the present study didn't indicate how much the animal stressed in the process
37
In the present study on average how long was in between catch and blood sampling of the sharks?
- 3 mins!
| L> baseline
38
Does the blood chemistry vary much from species to species?
YES its all over the place.
| - and it depends on how the shark is doing naturally vs being stressed from capture
39
Are sharks stills stressed out even if they are being reeled in slowly?
YES ... therefore you cannot really measure catch and release ...just catch and stress
40
Present study:
| - where were blood samples taken from?
- caudal area ( big artery in that area)
41
Present study:
| - what did they examine in the blood sample?
1. Whole Blood
- hematorit: packed blood cells in plasma... mostly RBC.
2. Plasma
- lactic acid
- glucose
- osmolality - overall osmolality in blood plasma
42
Present study:
| - what kind of needle was used?
18 gauge
43
Present Study Results:
| - How many sharks were examined?
24
44
Present study Results:
| - What were things that were found to not influence stress response/ show differences?
- shark size had no effect on stress response
- no differences measured between sexes (only 3 females were in group....not surprising since they segregate by sex...probably just a few stragglers from another group)
-
45
Present study Results:
| - All blod sampling was obtained within __ minutes of hooking. No difference was found between what?
- 3mins
- initial levels and the time it took to get samples
L> first three minutes were pretty much standard therefore maybe it is baseline... also this indicates that these animals have a quick increase in stress.
46
Present Study Results:
| - Glucose levels? How many peaks?Why?
- they increased 40% from the 15 min sample to the 60 min one.
- there were two large peaks...and they relatively plateaued afterwards ..likely due to the release of hormones!
47
Present study Results:
| - Lactate levels? What do all studies point to in regards to these levels? What is mysterious about it?
- rose in a linear fashion
L> it seemed to be the most important indicator of stress response in sharks....all studies point to this.
L> we don't know what happens later since they only go to a certain point prior to release
48
Present study Results:
| - what was found to be a key factor in determining the survival of the shark once it is released? (2)
- lactic acid levels
- glucose as well
- those released with ugh glucose levels are more likely to survive vs low.
49
Present study Results:
| - pH?
- it went from 6.86 to 6.78
L> this could be significant to sharks since it is on a log scale.... because we do not know the lethal limits in sharks
*** Humans" narrow range of 0.1 and anything outside of it for 3mins plus = dangerous
50
Present study Results:
| - Hematocrit?
- there was no change in blood cell packed volume
51
Present study Results:
| - When examining the graph with y= Plasma Glucose (mmol/L) and x= Time after capture (min) what do you notice?
- two peaks of glucose level
- One big increase in the first 15 minutes
- Second peak in the last 15 minutes
* * study didn't given any indication of what the shark was doing while these increases occurred
52
Present study Results:
| - When examining the graph with y= Plasma Lactate (mmol/L) and x= Time after capture (min) what do you notice?
- linear increase in lactate levels after capture...
| - likely it will continue to increase even after release!
53
Present study Results:
| - When examining the graph with y= pH level and x= Time after capture (min) what do you notice?
- Slight increase in pH up to 15 mins
- 15-30 mins pH decreased
- 30-45 mins pH increased
- 45- 60mins pH decreased
* * overall pH went from 6.86 to 6.78 = blood became more acidic
54
Present study Results:
| -When examining the graph with y= Plasma osmolality (mOsm/kg) and x= time after capture (mins) what do you notice?
- osmolality increased for the first 30mins and then from there onward it plateaued
* * significant increase ( 930mOsm/kg)
55
Present study Discussion:
| - ___ is an expected result of stress or exhaustive exercise in fishes.
- Hyperglycaemia
56
Present study Results:
| - Hyperglycaemia is also found in what two sharks?
- dogfish shark and dusky shark
57
Present study Results:
| - What causes hyperglycaemia? (biological explanation)
- Results from the release of catecholamines ( norepinephrine and epinephrine) at the beginning of stress/exercise.
- Corticosteriods ( cortisol) results in further increases of gluconeogenesis
58
Present study Results:
| - Initial readings in this study were found to be much higher or lower than in previous studies for hyperglycaemia ?
- higher!
- except in the bonnet head ....over 60mins.
L> maybe it was recently fed?
L> lower than in dusky shark over the 70min time frame?
** Dusky: larger shark so maybe different physiological makeup
59
Studies on Teleosts show signs of hyperglycaemia when there are increased levels of?
- glucose
60
What two neurotransmitters are involved with flight or fight response?
- epinephrine and norepinephrine
61
What is the difference between epinephrine and norepinephrine ?
- similar in structure except epinephrine has a different R group that makes its function different but they both have the same overall effect in the body...increasing blood flow and glucose levels to respond to stressful situations.
62
Present Study's Discussion:
| Why is it bad if sharks were recently fed before being caught?
- food that is broken down in the digestive tract...which releases glucose into the blood. We have no control over this since its in the natural environment BUT if a shark was caught than it was obviously not filled...and if they have recently been fed they usually regurgitate the food from the stress of the catch.
63
Present Study's Discussion:
| - Lactate levels elevated within __ mins which is indicative of what kind of respiration?
15
| anaerobic
64
Present Study's Discussion:
| - did lactate levels reach a plateau over the 60mins? Thoughts?
- NOPE
- it may take several hours for lactate to peak
- here the lactate levels are higher than any shark
- might be due to higher metabolic rate due to warmer temps in this studies ( others were taken at lower temps)
65
Present Study's Discussion:
| - What did they offer as a reason for why sharks may not survive after catch and release?
- it was attributed to the fact that lactate may peak several hours ager the observations being made from catch and release
66
Present Study's Discussion:
| - Was the pH drop only due to increasing lactic acid?
- no
- it was caused by other metabolic acids
L> The drop occurred before lactic acid increased enough to cause this change...something else must be going on!
- it takes time for it to circulate and process so maybe it is normal? not enough studies to determine this....
67
Present Study's Discussion:
| - Was the pH found in this study similar to that seen in others?
- yes it was similar in range of other studies
68
Present Study's Discussion:
| - What did previous studies show in regards to the drop in pH and the linear increase in lactic acid?
- that the pH drop occurred before lactic acid levels increased
- IN THIS STUDY lactate increased after 15 mins, pH did not drop until after 30mins
69
Present Study's Discussion:
| - did they measure countermeasures in sharks in regards to pH changes?
- Nope!
* *could have looked at ventilation rates....issues with pH = issues with ventilation ...look if gills are flaring at an increased rate to get more oxygen to get rid of more carbon dioxide!
70
Present Study's Discussion:
| - did the study measure CO2 levels in the blood?
- NOPE
| L> it is a DIRECT indicator of blood pH
71
Primer on Acid-Base Balance:
| - Acidosis?
- When the blood has too much acid or too little base resulting in a decrease in blood pH
72
Primer on Acid-Base Balance:
| - Alkalosis?
- When the blood has too much base or too little acid resulting in an increase in blind pH.
73
Primer on Acid-Base Balance:
| - What are the molecules involved with pH?
- CO2: carbon dioxide
- CHO3: bicarbonate ion: one of the most common buffering systems in certs
- H2CO4: carbonic acid
74
Primer on Acid-Base Balance:
| - What is the range for humans? Sharks?
- Humans : 7.357.45
(increase in H) ( decrease in H)
**too long on either side is dangerous!
- No clue what sharks normal range is! not enough investigation!
75
Primer on Acid-Base Balance:
| - Explain the significance of CO2
- it is the key ingredient in regulation?....it is a by product of cells...once secreted into the blood from cells it causes a release of hydrogen ions which changes pH..the more of these released the more acidic the blood is!
76
Primer on Acid-Base Balance:
| - Acidosis and alkalosis are categorized as either what two things?
- Metabolic or respiratory depending on their primary cause
77
Primer on Acid-Base Balance:
| - Metabolic acidosis and metabolic alkalosis cause?
- caused by an imbalance in the production of acids or bases and their excretion by kidneys!
L> aka the problem is within the kidneys ! ...lungs/gills have to compensate for it!
78
Primer on Acid-Base Balance:
| - Respiratory acidosis and respiratory alkalosis cause?
- caused primarily by changes in CO2 exhalation due to lung or breathing disorders.
L> aka changes in CO2 due to ventilation issue via gills problem...
L> if vent is low CO2 builds up in blood and the kidneys have to try and correct this.
79
Primer on Acid-Base Balance:
- stress response?
L> compensation?
- increases ventilation rate due to CO2 build up
| L> HCO3 soaks up H ions turning them into carbonic acid to keep the pH normal/stable
80
Primer on Acid-Base Balance:
| - did the study identify if there was a compensating mech?
- NOPE!
| L> trying to measure gill flaring is really hard with them struggling
81
Primer on Acid-Base Balance:
| - If blood becomes more basic there is a lot of what present above normal levels?
- bicarbonate ion
82
Primer on Acid-Base Balance:
| - excessive CO2 in the blood is an indication of what?
- the blood becoming more acidic
L> pCO2 = partial pressure of CO2 was sued to measure in study and they looked at HCO3 which they could have used int he discussion for describing pH changes.
83
Primer on Acid-Base Balance:
| - What is the Acid-Base mnemonic?
- ROME
1. RO
L> R - Respiratory
L> O - opposite
pH increases PCO2 decreases= Alkalosis
pH decreases, PCO2 increases = Acidosis
```
2. ME
L> M - Metabolic
L> E - Equal
pH increases, HCO3 increases: Alkalosis
pH decreases, HCO3 decreases..Acidosis
```
84
Present Study's Discussion:
| - Osmolality seemed to be corrected within __-__ minutes via?
- 30-45mins
- water transfer out of vascular compartments
L> Water is transferred out of the intercellular matrix and puts it back into the blood plasma to keep the osmolality normal..redistributing water levels in the body.
85
Present Study's Discussion:
- There was no significant relationship between the amount of time it took to obtain the initial blood sample and the ___,___, and ___.
- blood pH
- lactate
- glucose
86
Present Study's Conclusions:
- Stress response was ___ with elevated blood lactate levels. This may disrupt what balance? Leading to what kind of blood pH?
* * What about turnbulls input?
- rapid
- acid-base balance leading to decrease in blood pH but sharks in this study seemed to maintain acid-base balance
** Turnbull: sharks didn't maintain acid-base balance...study didn't look at compensatory measures to see if pCO2 (differences??) and HCO3 ( in plasma this would have to compensate and change)
L> pH is reflective of compensation !
87
Present Study's Conclusions:
- Hemoconcentration?
L>Alt causation?
- increased concentration of blood cell due to loss of fluid to tissues.... this did not appear evident as no hematocrit change occurred.
L> Problem with osmolality = concentration of blood...increased lactate levels can cause hemoconcentration. Study did not indicate an issue here though.
88
Present Study's Conclusions:
| - Low glucose levels may cause?
DEATH in those that are released from stressful situations
* higher= better chance of survival
* blood lactate is a key indicator for determining stress response
89
Present Study's Conclusions:
| - What were the levels of glucose like in this study?
- they were high - high chance of survival
90
Present Study's Conclusions:
| -Why is plasma osmolality more difficult to interpret?
- because sharks are iso-osmotic to hyper-osmotic to their surrounding environment and their osmolality changes with the salinity of the water ! **makes it hard for baseline
* * also this makes plasma osmolality a bad indicator of stress response !
91
Present Study's Conclusions:
| - What did the Atlantic sharp nose sharks in this study exhibit?
- highest plasma osmolality during the sumer when the salinity was also the highest
92
Use of reflexes as a stress response indicator? Example?
- Nicititating membrane used as a possible indicator of stress!
93
2014 Study by Gallagher et al:
| - describe briefly
- Physiological stress response, reflex impairment and survival of five sympatric shark species following experimental capture and release!
94
2014 Study by Gallagher et al:
| - What four reflexes did they examine?
1. Nicitating membrane
2. Bite response
3. Body flex
4. Equilibrium
95
2014 Study by Gallagher et al:
- Four reflexes examined:
1. Nictating membrane ?
- squirted it
| L> only good for those that had it
96
2014 Study by Gallagher et al:
- Four reflexes examined:
2. Bite response?
- putting something in front of the sharks jaws..if it is fully alert and functional it will bite down... if not this means its jaws are pretty much locked.
97
2014 Study by Gallagher et al:
- Four reflexes examined:
3. Body flex?
- its reps ones to probes...see if it responds via flexing
98
2014 Study by Gallagher et al:
- Four reflexes examined:
4. Equilibrium??
- if the shark starts to go sideways and down....aka if you have to get in and hold the shark upright it is very stressed! Basically it cannot swim on its own!
99
2014 Study by Gallagher et al:
| - What did they attach to the dorsal fin?
- spot tags! this is only used on animas /sharks that spend a lot of time at the surface..if at deep levels the tags are not very good...
* clamp is sued for short term
** drill holes in fin = long term
L> cable ties: keep tag in place.... ISSUE WITH LETHAL SAMPLING?
100
2014 Study by Gallagher et al:
| - What sharks were examined in this study?(5)
- Blacktip shark
- bull shark
- great hammerhead
- lemon shark
- tiger shark
* *tropical sharks
101
2014 Study by Gallagher et al:
| - How were the sharks captured?
- using circle hook drumlines
| L> hook timer is on it so they know when the shark was hooked = know how long shark was on the line
102
2014 Study by Gallagher et al:
| - what did they do in terms of with the sharks eyes?
- shot sea water at eye (3ml) at a distance of 4 cm using a gentle stream!
103
2014 Study by Gallagher et al:
| - did they draw blood?
- YEP
| - normal measurements first than blood sample to get an idea of size etc
104
2014 Study by Gallagher et al:
| - The bullshark is very ___ while the blacktip is very __ and ___. It uses its ___ to evade predators.
- robust
- skittish
- fast
- speed
* *life history = key factor
105
2014 Study by Gallagher et al:
| - why use circle hooks?
- because if it goes deep down the sharks throat it will come all the way up and get lodged near the jaw.... J shaped hooks will lodge anywhere and cause a lot of damage. ...if used they can interfere with respiration!
106
2014 Study by Gallagher et al:
| - Which sharks didn't trigger the timing mechanism on the hook?
- tiger sharks
- maybe bc they are very tolerant?
L> they swam around very slowly and gently !
107
2014 Study by Gallagher et al:
| - If the bobble near the hook is not at the surface what does this mean? Alt?
- a shark has been caught
| - Alt: some crabs can drag it down...so you may not have a shark !
108
2014 Study by Gallagher et al:
| - Why do most people use a stainless steal line?
- bc monofilament can be easily bitten through or a sharks tail can get rid of it via swipe.....This study sued a monofilament hook!
109
2014 Study by Gallagher et al:
| - What did the fight time range from?
9-185 mins!
110
2014 Study by Gallagher et al:
| - what was found about shark size?
- larger the shark = longer the fight time
111
2014 Study by Gallagher et al:
| - Do blacktips and great hammerheads do great on the lines for long periods ?
- no
| L> therefore they should be closer together in fight time
112
2014 Study by Gallagher et al:
| - what kind of activity is seen with blacktips once caught?
- spiral activity once caught...a lot of struggling ...they get tangled up and become suffocating....sometimes preyed upon by other sharks
113
2014 Study by Gallagher et al:
| - what happened to lemon sharks?
- normally just gave up and settled down..
114
2014 Study by Gallagher et al:
| - were all sharks mature?
yes aka good sizes
115
2014 Study by Gallagher et al:
| - Which sharks didn't receive a tag?
- blacktip and lemon sharks
| - dorsal gets black dots when stressed
116
2014 Study by Gallagher et al:
| - What does SPOT stand for?
- Smart Position or Temperature Transmitting
117
2014 Study by Gallagher et al:
| -Which sharks were not reflex tested or blood samples taken?
- those with SPOT gegges
118
2014 Study by Gallagher et al:
| - What two things had significant effects for lactate levels regardless of what?
- fight time and shark size!
| - species type
119
2014 Study by Gallagher et al:
| - Wide range of impairment with ___showing greatest degree, __ and ___ none, but ___ and __ exhibited as well.
- hammerheads
- lemon
- tiger
- black tip
- bull
120
2014 Study by Gallagher et al:
| - were pH changes found?
- No
- no difference in pH and flight time, nor carbon dioxide levels and flight time and size were found.
- these animals were not stressed enough to cause pH chanes (significant ones)
121
2014 Study by Gallagher et al:
| - when examining the data table what does R represent?
- the total combination of ranks for VpH, VpCO2, V lactate and Vreflex
* * higher rank number = very stressed
* * lower = least stressed
122
2014 Study by Gallagher et al:
| - List the sharks in order of least stressed to most based on R.
1. Tiger
2. Lemon
3. Great hammerhead
4. Bull
5. Blacktip
123
2014 Study by Gallagher et al:
| - In other studies Lactate levels were found to be a good indicator of?
post-release mortality in blues, thresher and makos!
124
2014 Study by Gallagher et al:
| - In this current study what shark died after release within 10 mins (only fought for 24mins)?
hammerhead
125
2014 Study by Gallagher et al:
| - No baseline available but captive studies indicate low lactate levels are what?
- normal
126
2014 Study by Gallagher et al:
| - Did the reflect tests yield a correlation with blood parameters?
- no
- but it mirrored physiological disturbance ( probably do not have t do a reflex shark for larger sharks because you can tell physically if it is stressed)
127
2014 Study by Gallagher et al:
| - discuss mortalities of study! What did they attribute these to?
1. hammerheads had low survival rates after release
2. only one tiger shark died via fishermen the rest survived
3. black tips had a high mortality rate
4. all lemon sharks survived!
* * attributed to swimming strategies! ... slow swimmer are not stressed out as quickly / badly vs fast swimming ones!
128
2014 Study by Gallagher et al:
| - What did the colourful graph with y= Lactate (mmil/L^-1) and x as total length (cm) and z= flight time in mins show??
- for black tip
- it showed increase in lactate levels as length increased of shark
- increase in lactate levels as the length increased and with it flight time did!
* *larger sharks had a higher fight time = higher lactate levels!
