The effects of mussel extracts The effects of mussel extracts on the heart rate of the lobster on the heart rate of the lobster

during night and day during night and day

IntroductionIntroduction

I. I. Nocturnal Behavior of Lobsters:Nocturnal Behavior of Lobsters:

• The Japanese Spiny Lobster is nocturnal and its activities The Japanese Spiny Lobster is nocturnal and its activities are controlled by underwater light levels (Kioke et al., are controlled by underwater light levels (Kioke et al., 1995,1996a,1996b).1995,1996a,1996b).

• Juvenile American Lobsters (Juvenile American Lobsters (Homarus americanusHomarus americanus) are ) are nocturnally active within or close to shelter (Lawton 87). nocturnally active within or close to shelter (Lawton 87).

• Field observations have shown lobsters with carapace two Field observations have shown lobsters with carapace two inches in length or greater are more active at night inches in length or greater are more active at night (Comm. Fish. Rev. 1968).(Comm. Fish. Rev. 1968).

• Presumably if lobsters are nocturnal than they must feed Presumably if lobsters are nocturnal than they must feed at night. Therefore being nocturnal and feeding at night at night. Therefore being nocturnal and feeding at night would increase their heart rate.would increase their heart rate.

II. II. Feeding:Feeding:

• Clawed and spiny lobsters can locate prey by means of their Clawed and spiny lobsters can locate prey by means of their chemoreceptors (Mcleese, 1970; Mackie, 1973)chemoreceptors (Mcleese, 1970; Mackie, 1973)

• The odor of live prey are sufficient enough to initiate searching The odor of live prey are sufficient enough to initiate searching behavior in lobsters (Hirtle and Mann, 78)behavior in lobsters (Hirtle and Mann, 78)

• We can presume that this searching behavior has an impact on We can presume that this searching behavior has an impact on the lobsters heart ratethe lobsters heart rate

III. III. Heart Rate:Heart Rate:

• A lobsters heart rate has been known to change according to A lobsters heart rate has been known to change according to physiological needs (Animal Behavior lab 3) physiological needs (Animal Behavior lab 3)

• Pollard and Larimer (1976) found that two peaks in heart rate Pollard and Larimer (1976) found that two peaks in heart rate occur, one during dusk and the other at dawn.occur, one during dusk and the other at dawn.

We wanted to know if mussel extract has an effect on the heart rate? 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 And is there a different effect on the lobsters heart rate during light

or dark conditions?or dark conditions?

Methods and MaterialsMethods and Materials

Animals and EnvironmentAnimals and Environment

• Lobsters were held in a 50 gal. tank exposed to a 14:10 LD Lobsters were held in a 50 gal. tank exposed to a 14:10 LD cycle, @25C with no food.cycle, @25C with no food.

Heart rate Heart rate MonitoringMonitoring

• Holes were drilled into the Holes were drilled into the carapace above the heart carapace above the heart 2cm apart (top figure).2cm apart (top figure).

• Wires were placed in the Wires were placed in the carapace and held on by carapace and held on by duct tape and super glueduct tape and super glue

• The wires were then The wires were then attached to an impedance attached to an impedance converter which was converter which was plugged into Powerlab A/D plugged into Powerlab A/D converter and then into a converter and then into a computer to record the heart computer to record the heart rate during testing (bottom rate during testing (bottom figure).figure).

Procedure: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).

Data AnalysisData 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 (p<.05)

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

TIME (min)

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

*

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

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

DiscussionDiscussion• Our data show for the first time that mussel extract had a Our data show for the first time that mussel extract had a

significant effect on the heart rate of lobsterssignificant effect on the heart rate of lobsters

• We did not find a significant difference on the heart rate We did not find a significant difference on the heart rate from the addition of mussel extract during light and darkfrom the addition of mussel extract during light and dark

• Heart rate and oxygen consumption have been found to Heart rate and oxygen consumption have been found to decrease during starvation in crabs (Aagaard, Warman, decrease during starvation in crabs (Aagaard, Warman, Depledge & Naylor 1995).Depledge & Naylor 1995).

• Captivity itself has been known to decrease respiration rate Captivity itself has been known to decrease respiration rate in crabs (Houlihan and Mathers 1985).in crabs (Houlihan and Mathers 1985).

• The lobsters were confined to movement in a shelter with The lobsters were confined to movement in a shelter with minimal light and no food. Thus maybe having an impact on minimal light and no food. Thus maybe having an impact on our results.our results.

• Heart rates have also been found to fluctuate due to Heart rates have also been found to fluctuate due to locomotion (Pollard and Larimer 76)locomotion (Pollard and Larimer 76)

• Clawed and spiny lobsters have been found to locate prey Clawed and spiny lobsters have been found to locate prey by means of there chemoreceptors (Mcleese, 1970; Mackie, by means of there chemoreceptors (Mcleese, 1970; Mackie, 1973).1973).

• Jasus Edwardsii ’89 found that New Zealand rock lobster Jasus Edwardsii ’89 found that New Zealand rock lobster were nocturnal, increasing there activity during the first were nocturnal, increasing there activity during the first hour of darkness and remaining active throughout the dark hour of darkness and remaining active throughout the dark periodperiod

• Further Test should be conducted to see if in fact the Further Test should be conducted to see if in fact the addition of mussel extract during the light and dark periods addition of mussel extract during the light and dark periods had no effect on the heart rate had no effect on the heart rate