**Ventilation and Oxygen consumption**

**Procedure:**

We measured the ventillation metabolism of the fish at two different temperatures: (25 C) and (15 C). For each fish,we prepared a 250 ml jar by filling it half full with water from the aquarium in which the fish was housed.we transfered the fish from its weighing beaker to the jar adding sufficient water to now fill the jar to about 80% of its capacity.

We placed the jar in the appropiate water bath. We left the jar unstoppered, and observe the activity of the fish for 10 minutes, or until its behavior stabilized. We placed a piece of sponge in the jar to help the fish stay calm. We used a two liter bottle of ice to keep the cold water tube cold.

During this time, we became familiar with the ventilation pattern of the fish so that we were able to count the movements of the gill covers (#/min.).

We counted the number of gill movements in 10 seconds and multiply by 6 to obtain the number of movements per minute.

When we were ready to begin the experiment, we filled the jars, one at a time, with the appropriate water and allowed a small amount to overflow. Quickly we inserted the calibrated oxygen probes and take the initial oxygen readings. We took readings on each fish at 15 minute intervals for one hour. Prior to each reading, we observed and recorded the ventilation rate of the fish (#/min.) and recorded on the data.

**Calculation:**

We converted oxygen concentration readings as mg of O2 /liter of water (ppm) to ml of O2 /liter of water by dividing each value by 1.43. we then divided each of the values for ml of O2/liter of water by the weight of the corresponding fish and enter it in the column ml/g. we used these values (ml/g) to determine oxygen consumption by subtracting the concentration at each time from the concentration at zero minutes. The value calculated for 60 minutes (ml of O2 consumed/g/hr) by definition is the oxygen quotient (Qo2). The mean of Qo2 at 25 C divided by the mean value at 15 C will give the Q10 for oxygen consumption.

Results:

The results show decreasing in oxyen consumption and decreasing in oxygen concentration as the temperature increases. As result of this experiment, Q2 at 25 C was 1.397, Q2 was 1.416, and the value of **Q10 was 0.98658**

Oxygen concentration at 25 C

Fish weight | 0 Minutes in (ml/g) | 15 Minutes In (ml/g) | 30 minutes In (ml/g) | 45 minutes In (ml/g) | 60 minutes in (ml/g) | |

Group three at 25 C | 1.42 | 2.61 | 1.44 | o.97 | 0.45 | 0.28 |

The mean of the whole groups at 25C | 1.20 | 3.23 | 2.74 | 2.41 | 2.03 | 1.83 |

Oxygen concentration at 15 C

Fish weight | 0 minutes in (ml/g) | 15 minutes In (ml/g) | 30 minutes in (ml/g) | 45 minutes In (ml/g) | 60 minutes in (ml/g) | |

Group three at 15 C | 1.45 | 2.93 | 2.20 | 2.10 | 2.58 | 2.11 |

The mean of whole groups at 15 C | 1.23 | 4.43 | 3.12 | 3.03 | 3.14 | 3.02 |

Oxygen consumption (ml/g) at 25 C

Group three | 1.18 | 1.65 | 2.16 | 2.33 |

The mean of the whole groups | 0.49 | 0.82 | 1.18 | 1.40 |

Oxygen consumption (ml/g) at 15 C

Group three | 0.73 | 0.83 | 0.35 | 0.82 |

Mean of the whole groups | 1.31 | 1.41 | 1.51 | 1.42 |