As the rate of respiration increases, the operculum opens and closes at a faster rate. Wait one minute and count the number of opercular openings in one minute. Wait 1 minute and then count the number of opercular openings for one minute. Record the temperature and respiration rate on Table A. Remove the ice from the beaker using a dip net and place in a sink. Be extremely careful when using the hotplate.
Serious burns can occur.
Pour 10 mL of warm water from the beaker into a graduated cylinder. Slowly add this warm water to the beaker with the fish by pouring water down the inside wall of the beaker. Continue to add warm water in 10 mL amounts until the temperature of the water in the beaker increases by 10 o F or 5 o F warmer than the initial temperature. Once the temperature has stabilized, remove any excess water so that the remaining water just covers the fish. Wait one minute and then count the number of times the operculum opens and closes for 1 minute.