Saddleback Journal of Biology - Saddleback College

Spring 2010 Biology 3B Paper
Method and Materials
This study was conducted in a series of
small fish bowls with a water temperature of
approximately 25 degrees Celsius. A total of 15
goldfish were tested in varying caffeine solutions; the
fish were divided up into three groups of five. Each
fish was individually introduced into a newly mixed
solution and was observed at 5 minutes 15 minutes
and 30 minutes from the time it was placed into its
caffeine solution, after the final observation the fish
was moved to another bowl and the testing
environment was rinsed and prepared with a new
solution for the next fish. The first group was tested
in a high caffeine environment made up of a 1000mL
solution of approximately 0.01mg caffeine per
100mL of water. The second group of five goldfish
was introduced into a weak caffeine environment of
approximately 0.005mg caffeine per 100mL of water.
These rates were based off of a human dosage
calculation of 9 mg per kg of body mass as a high
dose, and 4.5 mg per kg as a small dose, they were
scaled down accordingly to account for the
difference in body mass (Graham et al., 1991.)
The final group of goldfish was observed in 1000mL
of water with no caffeine in it, as a control. As a
caution the fish were kept 1 day before the
experiment started, in a controlled environment; as
caffeine is metabolized in healthy humans in
approximately 5 hours this ensured that any caffeine
that they might have been exposed to already would
be out of their systems (Meyer et al., 1991.) Before
the experiment had begun the fish were kept in a
communal bowl and after each fish was tested it was
moved to a separate post-test bowl. The source of the
caffeine was a dietary supplement consisting of
200mg of caffeine per tablet; these were crushed and
mixed via serial solution until they were the correct
strength. Respiration was observed by counting the
combined movements of the mouth and gills during a
period of 30 seconds and doubling the number to
account for one minute. Data has been compiled and
examined using an ANOVA test to determine any
significant statistical difference in goldfish
respiration due to aqueous caffeine.
included in the results as it would have thrown
off the data. However trends in respiration were
influenced by exposure to caffeine as is shown
in Table 1 seen below. Some behavioral
differences were noted during the course of the
observation, these included: active gulping at
the surface, speedy movements, and the
appearance of “holding breath” during which
time up to seven seconds might pass without
any movement of the mouth or gills. Of the three
fish who held their breath two were in the control
group and the last one was in the weak caffeine
environment, this last one only demonstrated
this behavior during the initial 5 minute
observation. Control #1 and Strong #4 had been
observed to be less dynamic than the rest
before and during the testing, and both died
before the following morning at least one hour
after the testing ended. Overall observed
behavior was somewhat more frantic
immediately after being swapped into the test
environment, this held true for the five fish in the
control group as well.
Trends in the average respiration per
minute as compared by environment show that
the goldfish who received caffeine demonstrated
significantly faster respiration than those in the
control group, as seen below in Figure 1. When
compared in ANOVA tests, the difference in
respiration between environments during the 5
minute period proved to be statistically
insignificant with a P-value of 0.41418. The
differences in the 15 minute period and 30
minute period demonstrated far more
significance with respective P-values of 0.00381
and 0.0099. From the resulting data it is clear
that there is a change in goldfish respiration in
the presence of caffeine. This implies that
goldfish likely have similar adenosine receptors
to ours and experience a stimulant response to
adenosine inhibition.
Results
Data collection was done in a 10
hour period in one day starting with the five fish
exposed to the strong solution. The second fish
in the strong solution group died two minutes
before his testing was set to begin, in the name
of thoroughness he was tested anyway;
needless to say his lack of breathing was not
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Saddleback Journal of Biology
Spring 2010