Goldfish (Carassius auratus) are ectothermic (cold-blooded) animals. This means that their body temperature changes with the change in the environmental temperature. When there is a low water temperature a fish slows down and so do its metabolic activities and when water temperatures are high, fish speed up and their metabolic processes increase as well. Proteins and enzymes are also affected by temperature changes. Oxygen is essential for the production of ATP from nutrients in cells; consequently oxygen must be delivered to a cell in sufficient amounts. Within fish, the counter-current exchange system allows for the efficient extraction of oxygen from the water by the gills. Basically when a fish takes in water, the flow of it is opposite to the flow of blood. As they rush by each other oxygen from the water is given to the blood (metabolic rate is also effected in animals that remain active because tend to consume more oxygen than those at rest). The size of a fish is relevant to oxygen consumption as larger fish consume more oxygen overall than smaller fish. The primary objective of this experiment is to note the effects of temperature on the oxygen consumption and ventilation rates of goldfish. We hypothesize that the ventilation rate of those fish that are subjected to warmer water temperatures versus colder temperatures will have a higher ventilation rate. The Fish in the warm water will consume more oxygen than the fish in the cold water. Overall oxygen will be mostly consumed by the fish that are in the warm water.
MATERIALS & METHODS
Split into groups of two, we were given Goldfish fairly similar in weight. We then transferred the fish to the appropriate jar from the beaker that was used to weigh them and added sufficient amounts of water to fill their capacities. After about 10 minutes, we hastily added the sponges to the jar pushing it halfway down the jar to assure no oxygen had entered the empty spaces between the water and the sponge. We then refilled the jars with the appropriate amounts of water and allowed a small amount to overflow. We then quickly placed the calibrated oxygen probes on and took the initial readings for the ventilation rate (Ventilations per minute), oxygen concentration (mg/L) and temperature (°C) for 0 minutes. The same readings were taken every 15 minutes and recorded onto Data Sheet I. The same procedure was used for the warm and cold water.
25°C GroupFish wt.(g) Oxygen values
mL/LmL/gmL/LmL/gmL/ LmL/ gmL/ LmL/ gmL/ LmL/ g
Table I. Conversion of Oxygen Values. Oxygen values, at any time interval, indicates the amount of oxygen still dissolved in the water and still potentially available to the Fish.
Oxygen consumption (mL/g)
Group 25 CTime (Minutes)
Group 15 C
Table II. Oxygen Consumption. The amount of...