The%20effects%20of%20mussel%20extracts%20on%20the%20heart%20rate%20of%20the%20lobster%20during%20night%20and%20day

1

• The effects of mussel extracts on the heart rate
  of the lobster during night and day

2
Introduction

• I. Nocturnal Behavior of Lobsters
• The Japanese Spiny Lobster is nocturnal and its
  activities are controlled by underwater light
  levels (Kioke et al., 1995,1996a,1996b).
• Juvenile American Lobsters (Homarus americanus)
  are nocturnally active within or close to shelter
  (Lawton 87).
• Field observations have shown lobsters with
  carapace two inches in length or greater are more
  active at night (Comm. Fish. Rev. 1968).
• Presumably if lobsters are nocturnal than they
  must feed at night. Therefore being nocturnal and
  feeding at night would increase their heart rate.

3

• II. Feeding
• Clawed and spiny lobsters can locate prey by
  means of their chemoreceptors (Mcleese, 1970
  Mackie, 1973)
• The odor of live prey are sufficient enough to
  initiate searching behavior in lobsters (Hirtle
  and Mann, 78)
• We can presume that this searching behavior has
  an impact on the lobsters heart rate
• III. Heart Rate
• A lobsters heart rate has been known to change
  according to physiological needs (Animal Behavior
  lab 3)
  
• Pollard and Larimer (1976) found that two peaks
  in heart rate occur, one during dusk and the
  other at dawn.
• We wanted to know if mussel extract has an effect
  on the heart rate?
• And is there a different effect on the lobsters
  heart rate during light or dark conditions?

4
Methods and Materials

• Animals and Environment
• Lobsters were held in a 50 gal. tank exposed to a
  1410 LD cycle, _at_25C with no food.

5

• Heart rate Monitoring
• Holes were drilled into the carapace above the
  heart 2cm apart (top figure).
• Wires were placed in the carapace and held on by
  duct tape and super glue
• The wires were then attached to an impedance
  converter which was plugged into Powerlab A/D
  converter and then into a computer to record the
  heart rate during testing (bottom figure).

6
Procedure

• Lobsters were placed in small plastic shelters
  that restricted their movement and visually
  isolated them
• They were exposed to a constant flow of sea water
  directed straight at their face delivered by ½
  inch tubing running down from each head tank
• 24 hr adjustment period before testing
• Five mussels blended with 100ml of water were
  added, using two 1ml pipettes, to the outlet of
  the head tank (left figure).

7

• Data Analysis
• About 10 sec of heart rate data were taken before
  and after each trial
• The data were combined by time of day
• A Students t-test was used to determine
  significant effects (plt.05)

8

• Results
• Figure 1 raw data before and after addition of
  mussel extract.
• Note the increase of heart rate about 10 sec
  after the addition of the extract.

Add Extract
TIME (min)
9

• Figure 2 the effect of heart rate before and
  after the addition of the mussel extract (Plt
  0.02) Note there is a significant effect on heart
  rate due to the addition of mussel extract smell

10

• Figure 3 the mean heart rate before the addition
  of mussel extract ( P 0.6828)

11

• Figure 4 the mean heart rate after the addition
  of the mussel extract at different times of the
  day (P 0.3954).

12
Discussion

• Our data show for the first time that mussel
  extract had a significant effect on the heart
  rate of lobsters
• We did not find a significant difference on the
  heart rate from the addition of mussel extract
  during light and dark
• Heart rate and oxygen consumption have been found
  to decrease during starvation in crabs (Aagaard,
  Warman, Depledge Naylor 1995).
• Captivity itself has been known to decrease
  respiration rate in crabs (Houlihan and Mathers
  1985).
• The lobsters were confined to movement in a
  shelter with minimal light and no food. Thus
  maybe having an impact on our results.

13

• Heart rates have also been found to fluctuate due
  to locomotion (Pollard and Larimer 76)
• Clawed and spiny lobsters have been found to
  locate prey by means of there chemoreceptors
  (Mcleese, 1970 Mackie, 1973).
• Jasus Edwardsii 89 found that New Zealand rock
  lobster were nocturnal, increasing there activity
  during the first hour of darkness and remaining
  active throughout the dark period
• Further Test should be conducted to see if in
  fact the addition of mussel extract during the
  light and dark periods had no effect on the heart
  rate