February 15-18, 2009 Washington State Convention Center Seattle ...

EVALUATION OF THE EFFECTS OF TEMPERATURE AND BODY MASS ON
RESPIRATION RATES OF PADDLEFISH Polyodon spathula USING RESPIROMETRY AND
DISSOLVED BLOOD GASES
Joshua T. Patterson*, Steven D. Mims, Richard J. Onders and Russell A. Wright
Aquaculture Research Center
Kentucky State University
Frankfort, KY 40601 USA
joshua.patterson@kysu.edu
Bioenergetics modeling is a valuable tool for assessing the trophic level dynamics in fish communities. These models are used
to estimate predator-prey relationships and food consumption. A significant component of any bioenergetics model is respiration.
An extensive production method for paddlefish known as reservoir ranching is currently in research and development
stages. The paddlefish is an emerging aquaculture species valued for both its firm, boneless, white meat and dark roe which
is processed into caviar. Development of a bioenergetics model for paddlefish is seen as a crucial step in expansion of reservoir
ranching. In the present study, paddlefish respiration was evaluated over the range of water temperatures found annually
in large reservoirs of the central United States, and over the range of weight classes attained by paddlefish during a growth
cycle.
Static respirometry was used to allow unrestrained paddlefish to swim at a constant speed. Dissolved oxygen (DO) concentrations
were monitored and recorded over time with a Strathkelvin Instrument meter mounted in two static respirometers of 500
L and 2300 L. Three water temperatures were used in the study: 10, 20, and 30°C. Paddlefish of three size classes were tested:
0-1.5 kg to correspond with stocker-size fish initially placed in reservoirs, >1.5 to 4.5 kg to correspond with fish in the 3 to 4
year age range, and >4.5 kg to correspond with harvest size fish. The smallest size class was tested in the 500-L respirometer
while the other size classes were tested in the 2300-L respirometer. Each size class was tested at each temperature with 8 to
10 replicates per trial group. Also, five fish from each size/temperature pairing were held in water with DO at saturation while
blood samples were drawn from the caudal vein. Subsequently, blood was drawn from at least five fish in each group after
spending time in the respirometer. Blood pH, PCO 2 , and PO 2 were compared between groups held at saturation and those from
the respirometer. Some results are presented below and will be discussed.
10° C Avg. 02
Consumption
(mg/h/kg)
Avg.
Temp
(° C)
Avg.
Weight
(kg)
20°
C
>4.5 kg 59.23 11.38 11.04 >4.5
kg
>1.5-4.5 80.08 10.38 3.80 >1.5kg
4.5
kg