EFFECTS OF WATER CONDUCTIVITY ON SURVIVORSHIP AND WEIGHT OF GOLDFISH (CARASSIUS AURATUS) Megan Russell, Rebecca Shuke, Samantha Smith ABSTRACT Water chemistry is an important characteristic of aquatic habitats as it directly affects the function of organisms. There are many variables affecting water chemistry, one of them being conductivity. The amount and type of dissolved solids can provide a great advantage or disadvantage to many organisms. We studied gold fish as they are household pets known for their low maintenance. Many do not consider or even monitor the water s conductivity in the home, so it was of interest to determine if water conductivity would have any effect on the fish. The study was performed to determine the relationship between conductivity and survivorship and growth rate of goldfish. There is little research done linking water conductivity and fish survival and growth rates, making this an important and challenging experiment. Our results did not show any conclusive correlation between these factors. Despite our lack of conclusive data, we believe that if less error had been involved there would have been greater results and a correlation could be found. Key words: Water conductivity, Carassius auratus, survivorship, dissolved oxygen INTRODUCTION Water chemistry plays an important role in the health of aquatic organisms. Organisms develop mechanisms to cope with fluctuations in water chemistry, but extreme amounts or lack of certain constituents can cause a degradation of conditions which could be detrimental to certain organisms. We decided to take a look at one specific variable of water chemistry, water conductivity, and looked at its effects on goldfish. There were very few studies that have been conducted on the affects of water conductivity on goldfish in our research, making our study particularly interesting. As goldfish are household pets for many due to their little required amount of care, the water used in their tanks is often not analyzed for its conductivity. Conductivity is defined as the ability or power to conduct or transmit heat, electricity, or sound (Lenntech Water Treatment and Purification, 2009). In water, conductivity is carried by ions in solution, thus the conductivity of the water increases as the amount of ions in solution increases. Studies of freshwater have shown that good mixed fisheries are supported by a water conductivity of 150-500 µs/cm (EPA: United States Environmental Protection Agency, 2010). And according to MBH Engineering Systems, the conductivity of typical tap water is within a range of 500-800 µs/cm (Heyda, 2006). In nature, the conductivity of water sources is affected most often by the soil composition or the bedrock which it flows through (LCRA, 2011). The location where the spring water was
obtained is characterized as being dominated by limestone, thus leading to the assumption that the major dissolved solid affecting the water conductivity would be calcium 2+. With the constant water flow across gills and intake of minerals, it is important to understand the possible effects water conductivity and specifically calcium concentrations on fish. Fish scales are also an important location of calcium deposition and metabolism to be considered. In fish, calcium has important structural functions as well as plays a role in muscle contraction, blood clot formation, nerve impulse transmission, maintenance of acid-base equilibrium, and activation of several important enzymes (Board on Agriculture, 1993). Carassius auratus is a member of the Carp family, which requires a relatively low amount of calcium (0.34 percent) in the environment for optimum growth (Board on Agriculture, 1993). With the use of absorption as the major method of obtaining nutrients and minerals for fish, they are very sensitive to the qualities and chemistry of their environment. Absorption allows for quick intake and use within the body system. Calcium is particularly important for the function of many organisms. This study will look at the effects of varying conductivity on the growth and survivorship of goldfish. We hypothesized that the fish in the highest conductivity water would have the greatest weight change and survivorship, while those in the lowest conductivity water would display the lowest amount of weight change and survivorship. FIELD SITE In order to test a variety of conductivities, spring water was collected from three sites of varying conductivity. Blue Spring had a high conductivity, Petersburg Spring had an intermediate conductivity, and Cold Spring had a low conductivity. Observation and experimentation took place in Ecology Laboratory B307. METHODS AND MATERIALS To perform our experiment, water from each of the springs was collected and brought back to the laboratory for filling and future cleaning of fish tanks. To begin the actual experimentation, 3 fish bowls were cleaned and conditioned by rinsing each tank three times with their respective spring water. Once the water was added to the tank, the initial conductivities and temperatures were recorded using the Oakton conductivity meter. We purchased enough goldfish to have ten goldfish in each bowl; the person at the store counted incorrectly because we ended up with one extra. Prior to adding the fish to their respective bowls, each were weighed and recorded. Tiny cups were used to weigh the fish. Water was placed in the cup and tared using the Ainsworth analytic scale. Then the fish was placed into the cup of water and weighed. The goldfish were fed every day within a two hour range to keep the feeding schedule fairly regular. During each of these feeding sessions the water conductivity was also measured to monitor along the way. Each bowl was cleaned once a week and received new water; on these cleaning days each of the fish was also weighed to track weight change. If there was a casualty along the way, the fish was removed on the day of discovery, and its weight was recorded into that week s weights. The dead fish were weighed in an empty cup containing no water. This experiment was run for a total of three full weeks. On the first day of the third week a bubbler was added to each of the tanks with fish still alive. RESULTS Tables 1, 2, and 3 were created to show the survivorship and average weight differences among the three springs over the course of three weeks. In all three tables, the average weight of the dead fish was
less than the average weight of the living fish. Figures 1 and 2 show that the survivorship dramatically decreased between weeks 1 and 2 in all three springs. Table 1. Weekly average weight of alive and dead fish for Blue Spring Blue Week Weight Alive (g) Weight Dead (g) Number Alive Number Dead 0 2.19118 0 10 0 1 2.77737 1.9981 7 3 2 2.3333 1.431 1 6 3 2.6439 0 1 0 Table 2. Weekly average weight of alive and dead fish for Petersburg Spring Petersburg Week Weight Alive (g) Weight Dead (g) Number Alive Number Dead 0 2.65586 0 11 0 1 2.49719 1.8145 10 1 2 0 1.327 0 10 3 0 0 0 0 Table 3. Weekly average weight of alive and dead fish for Cold Spring Cold Week Weight Alive (g) Weight Dead (g) Number Alive Number Dead 0 2.63214 0 10 0 1 2.19773 0 10 0 2 2.57875 1.1764125 2 8 3 0 1.03285 0 2 Figure 1. This graph shows the percentage of survivorship per week of goldfish in water from Blue, Petersburg, and Cold Springs
Figure 2. This graph shows the actual number of living gold fish per week in water from Blue, Petersburg, and Cold Springs. DISCUSSION Our initial hypothesis was that the higher conductivity of Blue Spring would result in a higher survivorship and weight gain while the lower conductivity of Cold Spring would have the least successful survivorship and lower weight gain. According to tables 1,2, and 3 our hypothesis was not supported. Our results were inconsistent and showed no significance. Figures 1 and 2 display they survivorship of the fish in each spring, which represents a poor correlation between survivorship and conductivity. Average weight gain was also observed throughout the 3 week interval. The tables were designed to include the average weight of the dead fish as well as the living fish to see if weight affected survivorship. In general, the average weight of the dead fish was always lower, in each spring, than that of he living fish. The inconsistency of the data can be contributed to many potential factors. The average weight change of all of the fish, dead as well as alive, did not show a consistent increase; in fact, during some weeks a weight loss was reported. This, along with the unexplainable mortality rates, leads us to several conclusions. To begin our study, there were 10 or 11 fish in each tank. While they were fed daily and cleaned weekly, we believe that the number of individuals per the given space could have simply been too large to support successful growth and survivorship. The potential for competition for food and space would be thus increased resulting in negative effects. As the study progressed, we observed that the fish seemed to be struggling for oxygen; they was a significant amount of deep gulping, seemingly gasping for air which led us to this conclusion. The amount of individuals also affects the total amount of waste produced per tank. After week one, Petersburg Spring had the largest number of living fish, however, during the following week all of the fish died. In Blue Spring, after week one there were seven fish alive but the next day four fish died, leaving only three living. These three fish seemed to be surviving much better than the ten fish in Petersburg Spring. Because so many fish died rapidly in Petersburg while the fish in Blue Spring had a steadier decline, leading us to believe the amount of waste, space, and competition must all have been factors. At the beginning of week three, we decided to add a bubbler into the tanks with living fish because of the observations showing that all of the fish were struggling. After the addition of the bubblers the fish seemed markedly less stressed. All of the situations that were present in each of the tanks must have caused a significant amount of stress on the fish, due to their poor survivorship. The stress was also observed qualitatively in terms of their physical actions: the fish in Blue Spring swam very erratically with their
muscles seemingly moving very rapidly, while the fish in Cold Spring seemed almost lethargic, often laying on the bottom of the bowl. Whether or not the conductivity had a direct effect on these observations, it cannot be determined due to the multitude of the stresses on the goldfish. The experiment was designed to include daily measurements of water conductivity, however, after the first week of recording, the conductivity meter was no longer available. However, during the first week of recording the conductivity in each tank increased throughout the week. We did find a replacement conductivity meter, which many have affected the observed readings, especially because the readings were not similar to that of the previous week. The readings were not included in this report due to the complete insignificance of the data found. There were a lot more variables in this experiment than expected, resulting in the varying and many types of error. Although not directly measured, we believe that the conductivity of these springs is a result of dissolved calcium, not sodium. We believe this because the geology of the area is characterized by limestone deposits. Calcium is necessary for muscle contraction, nerve impulse transmission, and enzyme activation in fish. Thus, as a result of the observed behavior of the fish along, we believe that calcium played a direct role in the results of this experiment. If this experiment were to be re-performed, there are several key changes that we believe are necessary for more accurate results. These changes include: the use of bubblers from the onset, dissolved oxygen should be measured along with conductivity, there should be an increased space per individual fish, and a complete understanding of the dissolved ions in the springs. According to the initial results of this study, there is no correlation between conductivity and the survivorship and growth of gold fish. Due to our inconclusive findings, the study should be performed again to see if there is any relationship. ACKNOWLEDGEMENTS We would like to thank Dr. Glazier for his incomparable help and guidance, Heather Kostick for all her support and for saving Spaz, Elura Fink for all her support, Joyce Eveleth for her time and compassion, and the 30 fish that lost their lives during this study. LITERATURE CITED Board on Agriculture. 1993. Nutrient Requirements of Fish. National Academy Press, Washington, D.C., USA. Chang, J., Wong.C., Davis,P., Soetaert, B., & Fedorow, C.S. 2003. Role of Ca2+ stores in dopamine-and PACAP- evoked growth hormone release in goldfish. Molecular and Cellular Endocrinology 206: 63-74. EPA: United States Environmental Protection Agency. 2010. Conductivity. From EPA: United States Environmental Protection Agency: http://water.epa.gov/type/rsl/monitoring/vms59.cfm Heyda, M. 2006. A Practical Guide to Conductivity Measurements. From MBH Engineering Systems: http://www.mbhes.com/conductivity_measurement.htm LCRA. 2011. Water Quality Indicators. From LCRA: Energy, Water, Community Services: http://www.lcra.org/water/quality/crwn/indicators.
Lenntech Water Treatment and Purification. 2009. Water Conductivity. From Lenntech Water treatment Solutions: http://www.lenntech.com/applications/ultrapure/conductivity/water-conductivity.htm Luz, R., Martinez-Alvares, R., De Pedro, N., & Delgado, M. 2008. Growth, food intake regulation and metabolic adaptations in goldfish (Carassius auratus) exposed to different salinities. Aquaculture 276:171-178 Mandic, M., Lau, G., Nijjar, M., & Richards, J. 2008. Metabolic recovery in goldfish: a comparison of recovery from sever hypoxia exposure and exhaustive exercise. Comparative Biochemistry and Physiology, Part C 148: 332-338